Effect of cold plasma pretreated hot-air drying on the physicochemical characteristics, nutritional values and antioxidant activity of shiitake mushroom

BACKGROUND

Shiitake mushroom is one of the most popular delicious vegetables, although fresh shiitake mushroom has short shelf life as a result of biochemical degradation. Drying can prolong the shelf life of mushroom. Additionally, application of cold plasma pretreatments (CPT) before drying can preserve the product quality, processing costs and nutritional values. Therefore, we aimed to explore the effect of cold plasma pretreated hot-air drying at 50, 60 and 70 °C on the physicochemical characteristics, nutritional values and antioxidant activity of shiitake mushroom.

RESULTS

Scanning electron microscopy micrographs showed that CPT induced the surface modification of fresh shiitake (such as cellular disarrangement, cellular shrinkages, disruption or break down of cell walls, and intracellular spaces and cavities) and facilitate the rapid drying than control samples. Furthermore, CPT improved the powder qualities (bulk density, water retention and swelling index) and preserved higher nutritional attributes (sugars, vitamins, phenolic acids contents and antioxidant activity) compared to the control groups.

CONCLUSION

Conclusively, CPT could be a suitable alternative technique for improving drying characteristics and preserving nutritional attributes of agro-based products. © 2021 Society of Chemical Industry.

Effect of ozone, lactic acid and combination treatments on the control of microbial and pesticide contaminants of fresh vegetables

BACKGROUND

Fruit and vegetable consumption has increased due to their tremendous health benefits. However, recent studies have shown that contaminated products may serve as vehicles for foodborne pathogens and harmful chemicals. Therefore, fresh vegetables must be decontaminated before consumption to ensure food safety.

RESULTS

In this study, the combined decontamination treatment of lactic acid (2.5 mL L-1 ) and ozone (9 mg L-1 ) for 10 min showed better efficacy in the removal of contaminants from fresh vegetables as compared to individual treatments. The combined treatment resulted in a reduction of 1.5-3.5 log CFU of native mesophilic bacteria per gram and 1.6-2.9 log CFU of artificially inoculated Escherichia coli per gram from tomato, cucumber, carrot and lettuce. The combined treatment also removed spiked pesticides, which represent artificial chemical contamination (28-97% chlorpyrifos and 62-100% λ-cyhalothrin residues), from fresh vegetables. No significant difference (P > 0.05) in various sensory attributes of vegetables was observed between untreated and treated (lactic acid and ozone) vegetables.

CONCLUSIONS

The combination treatment provides a novel approach to target two groups of contaminants using a single procedure. The combination treatment can be used as an alternative to currently used decontamination techniques for the supply of safe vegetables to consumers. © 2020 Society of Chemical Industry.

Biostimulants Application: A Low Input Cropping Management Tool for Sustainable Farming of Vegetables

Biostimulants, are a diverse class of compounds including substances or microorganism which have positive impacts on plant growth, yield and chemical composition as well as boosting effects to biotic and abiotic stress tolerance. The major plant biostimulants are hydrolysates of plant or animal protein and other compounds that contain nitrogen, humic substances, extracts of seaweeds, biopolymers, compounds of microbial origin, phosphite, and silicon, among others. The mechanisms involved in the protective effects of biostimulants are varied depending on the compound and/or crop and mostly related with improved physiological processes and plant morphology aspects such as the enhanced root formation and elongation, increased nutrient uptake, improvement in seed germination rates and better crop establishment, increased cation exchange, decreased leaching, detoxification of heavy metals, mechanisms involved in stomatal conductance and plant transpiration or the stimulation of plant immune systems against stressors. The aim of this review was to provide an overview of the application of plant biostimulants on different crops within the framework of sustainable crop management, aiming to gather critical information regarding their positive effects on plant growth and yield, as well as on the quality of the final product. Moreover, the main limitations of such practice as well as the future prospects of biostimulants research will be presented.

Antifungal activity of liquiritin in Phytophthora capsici comprises not only membrane-damage-mediated autophagy, apoptosis, and Ca2+ reduction but also an induced defense responses in pepper

Phytophthora capsici causes a severe soil-borne disease in a wide variety of vegetables; to date, no effective strategies to control P. capsici have been developed. Liquiritin (LQ) is a natural flavonoid found in licorice (Glycyrrhiza spp.) root, and it is used in pharmaceuticals. However, the antifungal activity of LQ against P. capsici remains unknown. In the present study, we demonstrated that LQ inhibits P. capsici mycelial growth and sporangial development. In addition, the EC₅₀ of LQ was 658.4 mg/L and LQ caused P. capsici sporangia to shrink and collapse. Next, LQ severely damaged the cell membrane integrity, leading to a 2.0-2.5-fold increase in relative electrical conductivity and malondialdehyde concentration, and a 65-70% decrease in sugar content. Additionally, the H₂O₂ content was increased about 2.0-2.5 fold, but the total antioxidant activity, catalase activity and laccase activity were attenuated by 40-45%, 30-35% and 70-75%. LQ also induced autophagy, apoptosis, and reduction of intracellular Ca²⁺ content. Furthermore, LQ inhibited P. capsici pathogenicity by reducing the expression of virulence genes PcCRN4 and Pc76RTF, and stimulating the plant defense (including the activated transcriptional expression of defense-related genes CaPR1, CaDEF1, and CaSAR82, and the increased antioxidant enzyme activity). Our results not only elucidate the antifungal mechanism of LQ but also suggest a promising alternative to commercial fungicides or a key compound in the development of new fungicides for the control of the Phytophthora disease.

Transgenic merA and merB expression reduces mercury contamination in vegetables and grains grown in mercury-contaminated soil

Arabidopsis, tobacco, tomato and rice with merA/merB expressed reduced mercury concentration of leaves, fruits or grains. These mercury-breathing plants produce agricultural products with acceptable levels of mercury from contaminated soil. Mercury contamination in plant food products can cause serious health risks to consumers. Transgenic approaches to enhance mercury phytoremediation have been accomplished with expression of bacterial merA and merB genes to convert toxic organic mercury to less toxic elemental mercury. However, little is known whether these genes can be used to produce safe foods from plants grown on mercury-contaminated land. We have used Arabidopsis and tobacco as model plants for leafy vegetables, and tomato and rice as representative fruit and grain crops to investigate whether merA and merB expression allows for production of safe foods from mercury-contaminated soils. Our results show that grown on heavily contaminated land with mercury, merA and merB expressing transgenic plants can produce vegetables, fruits and grains safe for human and animal consumption, while the wild-type plants cannot. The merA and merB transgenic plants can also efficiently remove mercury from soil. With increasing mercury contamination problems for the agricultural land worldwide, the use of the merA and merB genes can help produce safe food from mercury-polluted land and also remediate contaminated soils.

Nanoselenium Foliar Applications Enhance the Nutrient Quality of Pepper by Activating the Capsaicinoid Synthetic Pathway

Increasing the crop quality through enhancement of plant health is a challenging task. In this study, nanoselenium (nano-Se) was sprayed on pepper leaves, and the pepper components were compared to those of selenite. It was found that nano-Se (20 mg/L) resulted in a greater performance of plant health. It increased the chlorophyll and soluble sugar levels, which could activate phenylpropane and branched-chain fatty acid pathways, as well as AT3-related enzymes and gene expressions. These led to an enhancement for the synthesis of capsaicinoids, flavonoids, and total phenols. The nano-Se treatment also significantly promoted the expression of phyto-hormones synthesis genes, and consequently increased jasmonic, abscisic, and salicylic acid levels. Proline pathway-related compounds were increased, which could decrease the malondialdehyde and hydroxyl radical levels in crops. This study shows that nano-Se activated capsaicinoid pathways by enhancing photosynthesis and raising soluble sugar levels. The capsaicinoid contents in peppers were then increased, which consequently promoted the accumulation of secondary metabolites and antioxidants.

Effects of selenium on antioxidant enzyme activity and bioaccessibility of arsenic in arsenic-stressed radish

Consuming arsenic (As)-contaminated vegetables is the main route of As exposure in humans. The present study focused on the alterations in antioxidant enzymatic activities and As bioaccessibility in As-contaminated radish subjected to Se. Compared to the CK group, the total As content in raw radish was reduced by 27.5 ± 1.3%, and the bioaccessibility of As was reduced by 21.9 ± 2.3% in the 6 mg Se kg^-1 treatment group. The total As content in the treatment groups decreased first but then increased with increasing Se application in raw radish, gastric (G) fraction and gastrointestinal (GI) fraction, while the antioxidant activity exhibited the opposite trend. The results revealed that a low amount of Se effectively blocks the accumulation of As in radish, improves the antioxidant activity in radish and reduces the bioaccessibility of As. These findings provide new ideas for effectively alleviating the spread of As to the human body through the food chain.

Uptake and toxicity of di-(2-ethylhexyl) phthalate in Brassica chinensis L

This work focuses on the bioaccumulation and toxic effects of di-(2-ethylhexyl) phthalate (DEHP) in the leafy vegetable Shanghaiqing (SHQ) (Brassica chinensis L.). The accumulated DEHP amount in the edible part and roots of SHQ increased as the DEHP concentration in the soil increased. DEHP accumulation was higher in the roots than in the edible part of the plant. The root concentration factors and bioaccumulation factors for DEHP in SHQ were 0.13-2.49 and 0.03-2.00, respectively. The DEHP translocation factors were below 1.0, indicating that DEHP preferentially accumulated in plant roots. The DEHP risk index in the edible part of SHQ in relation to the human body and in terms of dietary exposure risk assessment was also below 1.0, indicating a low health risk. High DEHP concentrations caused 1) inhibition of SHQ growth, 2) an increase in SHQ chlorophyll and malondialdehyde contents and 3) a decrease in soluble sugar and vitamin contents. Low DEHP concentrations stimulated total superoxide dismutase, peroxidase and catalase activities, while high DEHP levels showed an inhibitory effect. DEHP presence in soil affected not only SHQ growth but also quality. Our results provide the data needed for the proper assessment of food safety and the ecological impact of DEHP contamination in agricultural soils.

Investigating the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the composition and ultrastructure of green leafy vegetables with important nutritional values

The global presence of pharmaceuticals in the environment has been particularly considered a concerning problem with unknown consequences. Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently prescribed drugs in the world, and as a result, they are commonly found in different environmental compartments. In the present work, we studied the effects of NSAIDs (diclofenac, ibuprofen, and naproxen) on the composition and ultrastructure of Atriplex patula L., S. oleracea, and Lactuca sativa L., three green leafy vegetables with significant nutritional value. Contaminant solutions of NSAIDs were applied every two days using concentrations of 0.1 mg L^-1, 0.5 mg L^-1, and 1 mg L^-1. After eight weeks of exposure of the green leafy vegetables to the selected NSAIDs, the chlorophylls (a + b), carotenoids (zeaxanthin, lutein, and ß-carotene), total polyphenol and total flavonoid contents, antioxidant capacity, and the ultrastructural modifications were determined. The obtained results indicated a moderate reduction in the assimilating pigments, total polyphenol and flavonoid contents. In addition, ultrastructural damages of the chloroplasts and cell walls were observed in the leaves of the selected vegetables, which were exposed to abiotic stress-induced by NSAIDs. All data collectively suggest that this group of drugs induced harmful effects on plants, and implicitly they may also negatively affected human health on the long term.

Variations in growth behavior, yield and DNA stability of two vegetable crops cultivated in radioactive spiked soils

Radioactive pollution comes on the top of pollution types that affect human life directly through damaging the human genome or indirectly via his food web. The current study focused on the evaluation of radiation effects of Assiut Thermal Power Plant (ATPP) ashes on two crop plants, potato and squash, in terms of morphological and molecular levels. More particularly, the specific activity concentrations were measured in Bq/kg, of the ²³⁸U (²²⁶Ra) and ²³²Th series, and ⁴⁰K-isotope for the untreated soil sample (control) and ATPP ash sample (represents the radioactive source with 100% concentration). Different concentrations of ATPP ash (0, 2, 4, 6 and 8%) were mixed with soil sample to study the effect of radioactively contaminated soil on potato and squash plants. The results of the present investigation revealed that the morphological characteristics of both potato and squash plants were changed, which reflected a steep regression in the values of all vegetative growth and yield traits. The alterations of the characteristic values were directly proportional to the radioactive ash concentration in the soil. In the same context, the molecular evaluation using PCR-based markers, e.g., ISSR and SCoT helps in understanding and explaining experimental observations at morphological level. ISSR/SCoT bands confirmed the toxicity and mutagenicity of radioactive ash samples at their present dose on both potato and squash plants. The present findings clearly explained the morphometric and genetic abnormalities in two of the main consumed crops by a human. Thus, the green area around the ATPP may disappear in the future due to increasing the pollution in terms of the radioactive component that directly attached to plants or indirectly by mixing with soil.

Liquiritin elicitation can increase the content of medicinally important glucosinolates and phenolic compounds in Chinese kale plants

BACKGROUND

Brassica oleracea var. alboglabra (Chinese kale) is an important vegetable grown in southern China. This study was aimed at searching for environmentally friendly and affordable approaches to increase the production of medicinally relevant glucosinolates and phenolic compounds in Chinese kale plants. For this purpose, the foliar application of liquiritin at 0 (control), 250, 500 and 750 ppm was tested starting from the four-leaf stage and repeated every two weeks until plants were two months old.

RESULTS

Foliar application of liquiritin in Chinese kale plants significantly increased glucosinolates and total phenolic content, in a dose-dependent manner. Compared with control plants, 2.3- and 1.9-fold increases in yields of glucosinolates and total phenolic content, respectively, were corroborated in Chinese kale plants treated with 750 ppm of liquiritin. Along with rises in the content of eight different glucosinolates, liquiritin elicitation effectively increased the concentration of glycosilated and acylated flavonoids and hydroxycinnamic acids. The expression of genes involved in glucosinolate and phenolic biosynthesis was significantly higher in liquiritin-treated plants as compared to controls.

CONCLUSIONS

Liquiritin elicitation is a feasible and environmentally friendly practice for increasing the production of medicinally important glucosinolates and phenolic compounds in Chinese kale, which may improve this plant's value as a nutraceutical food. This study also contributes to understanding the molecular mechanisms underlying liquiritin elicitation. This is the first report documenting the use of liquiritin for an elicitation purpose in plants. © 2019 Society of Chemical Industry.

Risk of cadmium, lead and zinc exposure from consumption of vegetables produced in areas with mining and smelting past

The study reveals links between disturbed geochemical environment being the result of mining and smelting activities with consumers exposure to toxic and carcinogenic metallic trace elements (MTEs). This study focused on evaluation on vegetable and soil pollution in family allotment gardens (FAGs), considering in the aspects of consumer exposure to cadmium, lead and zinc. Study material consisted of 219 soil samples from FAGs located in one of the most polluted areas in Poland, and 64 samples of edible plants. Contents of analyzed MTEs in topsoil in the studied area were spatially diversified and depended primarily on the location of industrial pollution sources. The average content of cadmium (0.52 mg kg-1 fresh weight) and lead (0.57 mg kg-1 fresh weight) in vegetables exceeded maximum permissible concentrations according to the European Quality Standards. Human health risk assessment was based on three scenarios of dietary exposure to cadmium, lead and zinc. In every scenario the highest average daily dose for all three elements was estimated for potatoes which are one of the main components of Poles' diet. Presented study showed that consumption of vegetables cultivated in FAGs located in Silesia Province may pose a significant health risk for their consumers.

Levels of heavy metals in soil and vegetables and associated health risks in Mojo area, Ethiopia

Health implications to the population due to the consumption of contaminated vegetables has been a great concern all over the world. In this study, the levels of heavy metals (Cr, Cd, Zn, Fe, Pb, As, Mn, Cu, Hg, Ni and Co) in soil and commonly consumed vegetables from Mojo area in central Ethiopia have been determined using Inductively Coupled Plasma Optical Emission Spectrophotometer (ICP-OES) and possible health risks due to the consumptions of the vegetables have also been estimated. The levels of As, Pb, Cd, Zn, Cu, Hg and Co were exceeded the reference level in agricultural soil. Likewise, As, Pb, Cd, Cr and Hg levels exceeded the recommended values in vegetable samples with concentrations ranging from 1.93–5.73, 3.63–7.56, 0.56–1.56, 1.49–4.63 and 3.43–4.23 mg/kg, respectively. It was observed that leafy vegetable (cabbage) has accumulated heavy metals to greater extent compared with tomato. The estimated daily intake (EDI) of toxic metals due to the consumption of the vegetables were below the maximum tolerable daily intake (MTDI). However, the total health quotient (THQ), calculated based on EDI of the heavy metals were found > 1 for As and Hg due to tomato consumption and for As, Hg and Co due to cabbage consumption, suggesting significant health risk. The health index (HI) due to the intake of toxic metals from the consumption of both vegetables were much > 1, with HI values of 7.205 and 15.078 due to tomato and cabbage consumption, respectively. This clearly suggests the possible adverse health effect to adult population from the consumption of tomato and cabbage from the study area. The total cancer risk (TCR) analysis have also revealed the potential adverse cancer risk induced by As, Cd, Hg, and Ni from the consumption of both tomato and cabbage as their TCR values were above the threshold level. Based on the results of this study, there would be a significant health risk (both non-carcinogenic and carcinogenic) to the consumer associated with the consumption of cabbage and tomato being cultivated in Mojo area. Consequently, we recommend a strict regulatory control on the safety of vegetables originated from the study area.

Effect of prohydrojasmon on total phenolic content, anthocyanin accumulation and antioxidant activity in komatsuna and lettuce

Prohydrojasmon has been reported to improve the quality of crops. However, most previous studies have investigated its application on fruits. Here, we evaluated the effect of prohydrojasmon on the growth and total phenolic content, anthocyanin content, and antioxidant activity in komatsuna (Brassica rapa var. periviridis) and lettuce (Lactuca sativa L.). Prohydrojasmon did not show any serious inhibitory effect. Prohydrojasmon applied to komatsuna at a concentration of 0.5 µM significantly increased the total phenolic content and anthocyanin content, and a concentration of 1 µM increased the antioxidant activity. In lettuce, prohydrojasmon at a concentration of 400 µM significantly increased the total phenolic content and anthocyanin content, while a concentration of 0.5 µM significantly increased the antioxidant activity. These results suggest that prohydrojasmon positively affects the phenolic compound and anthocyanin accumulation and antioxidant activity in komatsuna and lettuce without adversely affecting growth.

Differences in cadmium absorption by 71 leaf vegetable varieties from different families and genera and their health risk assessment

Leaf vegetables have strong capabilities to take up cadmium (Cd) compared to other vegetable varieties. Until now, the differences in Cd uptake and accumulation by leaf vegetables from different families and genera and the related health risks were unknown. To remedy this, we studied 71 leaf vegetables (multiple genotypes within 17 categories of vegetables) in soil cultivation experiments (3 Cd treatment levels). Results showed that at 2.12 mg kg^-1 Cd treatment, the dry weight of only five genotypic varieties from the families Brassicaceae and Asteraceae significantly decreased compared to the control, suggesting their weak Cd tolerances. Vegetables from the Brassicaceae, Asteraceae, Apiaceae, and Convolvulaceae families had stronger Cd absorption capabilities, whereas those from the Liliaceae and Amaranthaceae families had weaker ones. Cluster analysis found that the 17 vegetable categories could be divided into three groups: vegetables with high Cd accumulation capabilities were Lactuca sativa L.var. ramosa Hort. and Lactuca sativa var. longifoliaf. Lam. Vegetables with moderate Cd accumulation capabilities were bok choy, napa cabbage, choy sum, leaf mustard, Lactuca sativa L., Sonchus oleraceus L., celery, coriander, and water spinach. Vegetables with low Cd accumulation capabilities were cabbage, crown daisy, garlic chive, Allium ascalonicum, Gynura cusimbua, and edible amaranth. Estimated daily intake (EDI) and target hazard quotient (THQ) analysis results showed that 100% genotypes of vegetables from the Apiaceae and Convolvulaceae families had health risks; 100% genotypes of Lactuca sativa L., Sonchus oleraceus L., Lactuca sativa L. var. ramosa Hort., and Lactuca sativa var. longifoliaf. Lam from the Asteraceae family carried high risks. Of vegetables in the Brassicaceae family, 42.9% showed risks. Vegetables from the Amaranthaceae and Liliaceae families, Gynura cusimbua and crown daisy from the Asteraceae family, and cabbage from the Brassicaceae family all displayed relatively low risks (all 100%).

Effect of Imidacloprid Uptake from Contaminated Soils on Vegetable Growth

In the present study, the effect of imidacloprid uptake from contaminated soils on the growth of leaf vegetable Shanghaiqing was investigated. The result showed that during 35-day exposure, the concentration of imidacloprid (IMI) was in the order of vegetable shoots > vegetable roots > soil, indicating that IMI was more readily concentrated in vegetable shoots than in roots. Moreover, the biomass of IMI-treated vegetable shoots was comparable to that of the controls with early exposure, but was higher than that of the controls after 7-day exposure, showing that the test concentration of IMI could stimulate vegetable growth. The plant metabolic analysis of vegetable shoots using LC-QTOF/MS revealed that IMI may cause oxidative stress to the plant shoots with early exposure; however, the stressful situation of IMI seems to be relieved with the increase of some substances (such as spermidine and phenylalanine) with late exposure. Moreover, the upregulation of N-rich amino acids (glutamine, aspartate, and arginine) suggested that the process of fixing inorganic nitrogen in the plant should be enhanced, possibly contributing to enhanced growth rates. Additionally, four IMI's metabolites were identified by using MS-FINDER software, and the distribution of three metabolites in vegetable tissues was compared.

Comparison of efficacies of peanut shell biochar and biochar-based compost on two leafy vegetable productivity in an infertile land

The soils in northwest China are severely stressed with nutrient deficiency and water depletion, thus limiting crop production and sustainable agricultural development. Biochar-based amendments, tailored for specific soil issues, have raised great public interest for soil improvement and carbon sequestration. Peanut shell-derived biochar (PBC) and PBC-based amendment (PAD) obtained from composting were added at concentrations of 0%, 1.5%, 3%, and 5% (w/w) into light sierozem soil to compare their effects on growth of crown daisy (Chrysanthemum coronarium L.) and leaf lettuce (Lactuca sativa var longifoliaf L.). PBC had no significant effect on the yields of the two vegetables due to the second season growth, while addition of low concentrations of PAD (≤3%) significantly increased their yields by 15.8%-107%. The positive effect of PAD was primarily attributed to the improved soil qualities (e.g., water holding capacity (WHC), soil organic matter (SOM), electrical conductivity (EC)) and increased contents of available macronutrients (e.g., P and K), and micronutrients (e.g., B, Zn and Mn). However, addition of 5% PAD decreased the yield of crown daisy by 26.9% compared to that grown in untreated soil because of surplus nutrient input resulting in high EC. Overall, our findings demonstrated that the designed PAD synthesized from PBC compost had the potential to ameliorate the infertility in the soil and thus to improve vegetable yield.

Antioxidative enzymes activity and thiol metabolism in three leafy vegetables under Cd stress

The enrichment of Cadmium in vegetables is threatening human health. The study aimed to screen Cd low-enriched leafy vegetables and explore whether antioxidative enzymes and heavy metal chelators are synergistic defensive mechanisms. In this paper, the Cd accumulation and translocation of garland chrysanthemum (Chrysanthemum coronarium L.), spinach (Spinacia oleracea L.), and lettuce (Lactuca sativa L.) were examined by soil pot culture and hydroponic experiments. The responses of oxidative stress markers, antioxidative enzymes activity, and thiol pool (cysteine, γ-glutamylcysteine, glutathione, and phytochelatins) content to Cd stress were assayed. The results showed that Garland chrysanthemum was Cd low-uptake species. The soil Cd safety thresholds for spinach, lettuce, and garland chrysanthemum were 0.41, 0.49, and 9.10 mg kg-1, respectively. The order of root phytochelatins (PCs) concentration was consistent with that of plant tolerance index (TI): garland chrysanthemum > spinach > lettuce. While the order of the ratio of shoot Cd to root Cd (SR ratio) was exactly the opposite of that of TI. In lettuce root, activity of superoxide dismutase, peroxidase, and catalase decreased significantly under Cd stress. Nevertheless those parameters in the roots of spinach and lettuce maintained steady, or even enhanced. In conclusion, the Cd translocation and partition in plant, antioxidative defense, and PCs homeostasis played an important role in the Cd tolerance of vegetables.

Composting of municipal solid waste by different methods improved the growth of vegetables and reduced the health risks of cadmium and lead

Reutilization of putrescible municipal solid wastes (MSW) in agriculture can provide valuable plant nutrients. However, it may pose serious noncarcinogenic health risks for a human when contaminants, especially the heavy metals in MSW, end up in plants through the waste-soil-plant continuum. This study examined the effects of composting methods viz. aerobically (AC), anaerobically (ANC), and aerobic-anaerobically (AANC) composted MSW material on (i) fertilizer value: vegetable yield, nitrogen (N) mineralization, and apparent N recovery (ANR); and (ii) associated health risks: selected heavy metal concentration, daily intake of metals (DIM), health risk index (HRI), hazard index (HI), and target hazard quotient (THQ) when applied to a loamy soil. All the aforementioned compost materials were incorporated into the sandy loam soil filled in pots and carrot and spinach were cultivated for 85 and 90 days, respectively. After soil application, between 51 and 56% of the applied organic N was mineralized from ANC material, while the values in case of AC and AANC were 26-31% and 34-40%, respectively. Consequently, dry matter yield and vegetable N uptake from composts were in the order ANC > AANC > AC (P < 0.05). Further, vegetable ANR was the highest from ANC (56 and 56%) than AANC (42 and 45%), and AC (30 and 33%) for spinach and carrot, respectively (P < 0.05). Interestingly, plant uptake of lead and cadmium was lowest from ANC as compared to AC or AANC (P < 0.05), irrespective of the vegetable type. Consequently, DIM, HRI, and THQ for these metals were substantially lower in the former as compared to the latter compost materials. Further, HI from ANC material was 50% lower over the unfertilized control indicating the absence of noncarcinogenic human health risks via vegetable intake. This all indicates that from viewpoint of sustainable waste recycling in agriculture, anaerobic composting is superior to the other composting methods.

Enantioselective degradation of the chiral alpha-cypermethrin and detection of its metabolites in five plants

Alpha-cypermethrin (α-cypermethrin), an important chiral pyrethroid insecticide, is frequently detected in human samples. Because of the possible human health risks caused by α-cypermethrin, we studied dynamics, residues, and metabolism of α-cypermethrin in five common vegetables (tomato, cucumber, rape, cabbage, and pepper) on enantiomeric levels after foliar spray. α-Cypermethrin was qualified by a HP-5 column and its enantiomers could be separated by gas chromatograph (GC) using a BGB-172 chiral column. The results of degradation showed that α-cypermethrin dissipated rapidly in vegetables with half-lives being only 2.85-8.88 days. Stereoselective degradation was observed on pepper and cucumber while the two metabolites (cis-DCCA and 3-PBA) of α-cypermethrin were not detected during its dissipation in all plants. This is the first evidence of enantioselective degradation of α-cypermethrin in the five common vegetables and the results should be considered in future environmental risk and food safety evaluations.

High Reticulocyte Count with Abnormal Red Blood Cell Morphology in Normal Wistar Rats after Garlic Administration

Despite the high acceptability of Allium sativa (Garlic) as a remedy for many diseases as earlier stated by manyresearchers, previous studies have shown that chronic and unregulated consumption of garlic may result to intra vascularhaemolytic anaemia in rats. The present study was conducted to examine the effect of crude extract of garlic on microscopicstatus of red blood cells and some other haematological indices of normal albino rats. The animals were grouped into two;group 1 were normal animals treated with water while group 2 were normal animals administered 150mg/kg body weight ofcrude extract of garlic on alternate days for three weeks. At the end of three weeks treatment, blood samples obtained fromthe tail vein of the rats were used for haematological indices and erythrocyte morphology. The values obtained wereexpressed as Mean± SEM and compared using student t test. The results showed that there was no significant difference inthe PCV which was 43.20 ± 0.80% and 45.00 ± 0.36% in both control and experimental groups respectively. However, theRBCs were significantly decreased (P< 0.05) from 166.80 ± 3.44 x106 µL-1 in the control group to 87.80 ± 9.34 x106 µL-1 inthe treatment group. The percentage reticulocyte counts on the other hand significantly increased from 2.60±4.25% in controlgroup to 11.20± 16.4% in treated group. Fragmented RBCs with a lot of schistocytes with adequate platelets were seen onperipheral blood film of crude garlic treated rats as compared to control. Our results suggested intravascular haemolysis andnumerous reticulocytes on blood film confirmed our view on bone marrow response. The presence of schistocytes andacanthocytes may be an indication that the liver is involved in the observed effect.

Effect of lead on plant availability of phosphorus and potassium in a vegetable-soil system

Two typical red soils were sequentially cultivated with celery (Apium graveolens L.) and Chinese cabbage (Brassica chinensis L.) in a greenhouse to determine the effect of lead (Pb) on plant availability of phosphorus (P) and potassium (K) in the soils. The concentrations of available P as estimated by the 0.05 mol L^-1 HCl-0.025 mol L^-1 (1/2 H₂SO₄) extraction and available K estimated by the NH₄OAc extraction method in the crop-free soils were not affected by Pb treatment. Plant P concentrations in the above-ground part of celery and Chinese cabbage exposed to Pb were either lower or showed no significant difference to the control.

A multifaceted approach to harness probiotics as antagonists on plant based foods, for enhanced benefits to be reaped at a global level

Investigations into probiotics have focused on their health benefits thus far, with some of the findings finally reaching the food and pharmaceutical industries, which have used them for commercial purposes. In biocontrol research some microbes, mainly isolated from plants, have shown antagonism towards both enteric and plant pathogens, and some of them represent probiotic species. Fresh fruits and vegetables are regarded as health-promoting dietary constituents, and if probiotics could be used to control the pathogens on them then they could turn out to be even healthier. The fresh produce industry still depends on agrochemicals and the increase in the demand for high-priced organically grown produce indicates consumer concerns regarding the use of agrochemicals. If the potential of probiotic organisms to serve as biocontrol agents for fresh produce is exploited, all fresh produce can be made as safe as organically grown produce, and much more wholesome. This review appraises the feasibility of such a move by evaluating how research has progressed in both disciplines (probiotic and biocontrol) and suggests sharing results from research via information technology, efficient collaboration, and the use of novel molecular biological tools to achieve the objective of probiotic antagonists. © 2018 Society of Chemical Industry.

Effects of cadmium and copper mixtures to carrot and pakchoi under greenhouse cultivation condition

A pot experiment was undertaken to investigate the effects of Cd and Cu mixtures to growth and nutrients (sugar, carotene or vitamin C) of carrot and pakchoi under greenhouse cultivation condition. The study included: (a) physical-chemical properties of soil and soil animals in response to Cd and Cu stress; (b) bioaccumulation of heavy metals, length, biomass, contents of sugar and carotene (vitamin C) of carrot and pakchoi; (c) estimation the effects of Cd and Cu mixtures by multivariate regression analysis. The results implied that heavy metals impacted negative influence on soil animals' abundance. The metals contents in plants increased obviously with Cd and Cu contamination in soil. The biomass production and nutrients declined with Cd and Cu contents increasing. Cd (20 mg kg^-1) treatment caused maximum reduction of sugar content (45.29%) in carrot root; maximum reduction in carotene content (75.73%) in carrot, 75.1% sugar content reduction and 70.58% vitamin C content reduction in pakchoi shoots were observed with addition of Cd (20 mg kg^-1) and Cu (400 mg kg^-1) mixture. The results of multivariate regression analysis indicated that combination of Cd and Cu exerts negative effects to both carrot and pakchoi, and both growth and nutrients were negatively correlated with metals concentrations. It is concluded that the Cd and Cu mixtures caused toxic damage to vegetable plants as Cd and Cu gradient concentrations increased.

Phytoavailability, bioaccumulation, and human health risks of metal(loid) elements in an agroecosystem near a lead-zinc mine

Soil near a Pb-Zn-Mn mine was polluted by mining, which may have an impact on human health via the food chain. To evaluate the pollution effects, arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), lead (Pb), and zinc (Zn) in vegetables were determined by inductively coupled plasma atomic emission and mass spectrometry. Lead species were analyzed by X-ray absorption near-edge structure (XANES). Phytoavailability of the elements was evaluated by bioaccumulation of the elements, the sequential extraction procedure, Pb species, and plant uptakes. The target health quotient (THQ) was calculated to evaluate the human health risks. It was found that (1) high concentrations of As, Cd, Cr, and Pb were detectable in vegetables, and bioaccumulation was in the order of Mn > Zn > Cr > Pb > Cu > As > Cd; (2) phytoavailability of the elements was controlled mainly by the soluble fraction, and a linear relationship observed between the soluble fraction and bioaccumulation; (3) a new Pb-fulvic acid complex (Pb-FA) was identified by XANES in rhizosphere soil, and high content of Pb organic matter (60%) and soluble Pb (18%) were found; (4) both Cd and Zn accumulated in both of the Amaranthaceae and the Apiaceae families, indicating that the plants in the same family have the same bioaccumulation trend for the elements in the same group; (5) agricultural activities and plant growing increased phytoavailability of As, Cd, Cu, Pb, and Zn by decreasing the residual and raising the soluble and extractable fractions; (6) arsenic is top of the high health risks, followed by Pb, Cd, and Mn. Coriander, celery, and spinach were the top three highest health risks in the area.

Spatial distribution, risk and potential sources of lead in soils in the vicinity of a historic industrial site

Because of measures taken by local and national government agencies to control releases of metals, former industrial sites in China that are contaminated with lead (Pb) in soils have been abandoned. Compared with historic sites themselves, little attention has been paid to contamination with Pb in areas surrounding these sites. In this study, a method by integrating sequential extraction and isotopic fingerprinting was proposed to reveal the key fractions of Pb contaminants in soils, trace their sources and determine the subject of liability for remediation. Topsoils from near a historic site, where lead oxide was produced, were found to be contaminated. Concentrations of Pb in soils were inversely proportional to distances from the industrial site and depth in soils. The predominant form of Pb was the Fe/Mn-oxide-bound fraction (FM3), which accounted for from 53.39% to 82.07% of total concentrations of Pb. Concentrations of Pb in vegetables produced on contaminated soils exceeded those allowed in food for consumption by humans. An assessment of hazards and risks posed by consumption of vegetables grown on these soils indicated relatively high potential for adverse effects on local residents around the closed plant. By use of isotopic finger printing for Pb, the abandoned factory was determined to be the most likely source of Pb in topsoils, especially fraction FM3. To mitigate exposures of people to Pb via consumption of locally produced food, recommended strategies should target legacy sources of Pb to soils in the vicinity of this historic industrial site.

[Effects of Tetracycline Antibiotics on Growth and Characteristics of Enrichment and Transformation in Two Vegetables]

Pot experiments were carried out to study different levels (0, 50, and 150 mg·kg-1) of three tetracycline antibiotics[tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC)] on the growth, concentration of tetracycline antibiotics, and their characteristics of enrichment and transformation in two kinds of vegetables (lettuce and Chinese cabbage). The results showed that the fresh weight of shoots and roots of lettuce decreased by 1.56%-26.84% and 17.36%-51.04%, respectively, when exposed to tetracycline antibiotics compared to the control, while the fresh weight of shoots and roots of Chinese cabbage increased by 3.7%-7.3% and 3.1%-82.2%, respectively. The stomatal conductance (Gs) and transpiration rate (Tr) of lettuce and cabbage increased when exposed to tetracycline antibiotics, while the net photosynthetic rate (Pn) of lettuce decreased by 32.43%-82.43% at 150 mg·kg-1 of TC compared to the control. Compared to the control, the activities of SOD in lettuce and cabbage decreased 29.17%-223.12% when exposed to tetracycline antibiotics, and the lowest activities of SOD in lettuce and cabbage were found in OTC treatments. The highest content of MDA in lettuce and cabbage was observed at 150 mg·kg-1 of TC (except for lettuce leaves). The contents of tetracycline antibiotics in the shoots and underground portions of Chinese cabbage were higher than that of lettuce, and higher contents of tetracycline antibiotics in vegetables were found with the CTC treatments. The residual amount of antibiotics in lettuce soil was higher than that in the Chinese cabbage soil, and the highest residual amount in the soil was observed with the OTC treatment. The bioconcentration factors (BCF) and transport factor (TF) of Chinese cabbage were, respectively, 1.07-7.35 and 1.15-2.25 times that of lettuce. OTC and CTC were more easily concentrated in the two vegetables. Therefore, OTC and CTC may bring a higher ecological risk.

Response of nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and antioxidant activity in selected vegetable amaranth under four soil water content

Four selected vegetable amaranths were grown under four soil water content to evaluate their response in nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and total antioxidant activity (TAC). Vegetable amaranth was significantly affected by variety, soil water content and variety × soil water content interactions for all the traits studied. Increase in water stress, resulted in significant changes in proximate compositions, minerals (macro and micro), leaf pigments, vitamin, total polyphenol content (TPC), and total flavonoid content (TFC) of vegetable amaranth. Accessions VA14 and VA16 performed better for all the traits studied. Correlation study revealed a strong antioxidant scavenging activity of leaf pigments, ascorbic acid, TPC and TFC. Vegetable amaranth can tolerate soil water stress without compromising the high quality of the final product in terms of nutrients and antioxidant profiles. Therefore, it could be a promising alternative crop in semi-arid and dry areas and also during dry seasons.

Effects of waste water irrigation on soil properties and soil fauna of spinach fields in a West African urban vegetable production system

The usage of inadequately processed industrial waste water (WW) can lead to strong soil alkalinity and soil salinization of agricultural fields with negative consequences on soil properties and biota. Gypsum as a soil amendment to saline-sodic soils is widely used in agricultural fields to improve their soil physical, chemical and hence biological properties. This study aimed at analysing the effects of intensive WW irrigation on the structure and composition of soil-dwelling arthropods on spinach fields (Spinacia oleracea L.) in a West African urban vegetable production system. We used gypsum as a soil amendment with the potential to alleviate soil chemical stress resulting in a potentially positive impact on soil arthropods. A total of 32 plots were established that showed a gradient in soil pH ranging from slight to strong soil alkalinity and that were irrigated with WW (n = 12) or clean water (CW; n = 20), including eight plots into which gypsum was incorporated. Our study revealed a high tolerance of soil-dwelling arthropods for alkaline soils, but spinach fields with increased soil electrical conductivity (EC) showed a reduced abundance of Hymenoptera, Diptera and Auchenorrhyncha. Arthropod abundance was positively related to a dense spinach cover that in turn was not affected by WW irrigation or soil properties. Gypsum application reduced soil pH but increased soil EC. WW irrigation and related soil pH affected arthropod composition in the investigated spinach fields which may lead to negative effects on agronomical important arthropod groups such as pollinators and predators.

Biological changes of green pea (Pisum sativum L.) by selenium enrichment

Supplement of common fertilizers with selenium (Se) for crop production will be an effective way to produce selenium-rich food and feed. The value of green pea seeds and forages as alternative protein source can be improved by using agronomic biofortification. Therefore, biological changes of green pea (Pisum sativum L.) and influences of inorganic forms of Se (sodium selenite and sodium selenate) at different concentrations on the accumulation of magnesium (Mg) and phosphorus (P) were investigated in greenhouse experiment. 3 mg kg-1 of selenite had positive effects to enhance photosynthetic attributes and decrease lipid peroxidation significantly. At the same time, Se accumulation increased in all parts of plant by increasing Se supply. Moreover, Mg and P accumulations were significantly increased at 3 mg kg-1 selenite and 1 mg kg-1 selenate treatments, respectively. By contrast higher selenite concentrations (≥30 mg kg-1) exerted toxic effects on plants. Relative chlorophyll content, actual photochemical efficiency of PSII (ФPSII) and Mg accumulation showed significant decrease while membrane lipid peroxidation increased. Thus, the present findings prove Se biofortification has positive effects on biological traits of green pea to provide it as a proper functional product.

Analysis of the use of microcystin-contaminated water in the growth and nutritional quality of the root-vegetable, Daucus carota

Toxic cyanobacterial blooms are often observed in freshwaters and may reflect the increased eutrophication of these environments and alterations in climate. Cyanotoxins, such as microcystins (MCs), are an effective threat to many life forms, ranging from plants to humans. Despite the research conducted to date on cyanotoxins, the risks associated to the use of contaminated water in agriculture require further elucidation. To tackle this aim, a research was conducted with the root-vegetable Daucus carota. The specific aims of this work were the following: (i) to evaluate the effects of MC-LR on the plant growth and photosynthesis; (ii) to evaluate the nutritional quality of carrot roots; and (iii) to measure bioaccumulation. To this purpose, young carrots were grown in soil during 1 month in natural conditions and exposed to Mycrocystis aeruginosa aqueous extracts containing environmentally realistic concentrations of MC-LR (10 and 50 MC-LR μg/L). The results showed that MC-LR may decrease root growth after 28 days of exposure to 50 μg/L and increase photosynthetic efficiency. We also observed changes in mineral and vitamin content in carrots as a result of the exposure to contaminated water. Moreover, MC-LR was detected in carrot roots by ELISA at very low concentration 5.23 ± 0.47 ng MC eq./g FW. The soil retained 52.7 % of the toxin potentially available for plants. This result could be attributed to MC-LR adsorption by soil particles or due to microbial degradation of the toxin. We conclude that the prolonged use of MC-LR-contaminated water may affect crop growth, alter the nutritional value of vegetable products, and potentiate contamination.

Effect of di-n-butyl phthalate (DBP) on the fruit quality of cucumber and the health risk

Di-n-butyl phthalate (DBP) widely used as plastic films' plasticizer, can cause agricultural pollution which is of increasing concern because of the food safety issues. Cucumber ( Cucumis sativus Linn.), commonly cultured in greenhouse, was exposed to DBP stress to gain more information about the ecological risk of DBP in this study. Changes of DBP residues and fruit quality of cucumber at different DBP concentrations (0, 5, 10, 20, 40 mg/kg of dry soil) were investigated in pot experiments using an agricultural soil under greenhouse condition, respectively. DBP residue in cucumber fruits ranged from 0.5326 to 1.8938 mg/kg, and the quality of cucumber fruits (organic acids, vitamin C, soluble protein, and soluble sugar) were influenced by DBP stress. Moreover, the health risk assessment was evaluated by estimate daily intakes (EDI) and the target hazard quotient (THQ) was analyzed. Under 40 mg/kg DBP condition, the highest value of EDI was 2.49 μg/kg bw/day and the THQ ranged from 0.000700 to 0.0249. Although the risk of DBP in cucumber fruits was lower than the threshold limit value of risk, the potential health risk was not a negligible issue.

Effect of Leaf Surface Chemical Properties on Efficacy of Sanitizer for Rotavirus Inactivation

The use of sanitizers is essential for produce safety. However, little is known about how sanitizer efficacy varies with respect to the chemical surface properties of produce. To answer this question, the disinfection efficacies of an oxidant-based sanitizer and a new surfactant-based sanitizer for porcine rotavirus (PRV) strain OSU were examined. PRV was attached to the leaf surfaces of two kale cultivars with high epicuticular wax contents and one cultivar of endive with a low epicuticular wax content and then treated with each sanitizer. The efficacy of the oxidant-based sanitizer correlated with leaf wax content as evidenced by the 1-log10 PRV disinfection on endive surfaces (low wax content) and 3-log10 disinfection of the cultivars with higher wax contents. In contrast, the surfactant-based sanitizer showed similar PRV disinfection efficacies (up to 3 log10) that were independent of leaf wax content. A statistical difference was observed with the disinfection efficacies of the oxidant-based sanitizer for suspended and attached PRV, while the surfactant-based sanitizer showed similar PRV disinfection efficacies. Significant reductions in the entry and replication of PRV were observed after treatment with either disinfectant. Moreover, the oxidant-based-sanitizer-treated PRV showed sialic acid-specific binding to the host cells, whereas the surfactant-based sanitizer increased the nonspecific binding of PRV to the host cells. These findings suggest that the surface properties of fresh produce may affect the efficacy of virus disinfection, implying that food sanitizers should be carefully selected for the different surface characteristics of fresh produce.

IMPORTANCE

Food sanitizer efficacies are affected by the surface properties of vegetables. This study evaluated the disinfection efficacies of two food sanitizers, an oxidant-based sanitizer and a surfactant-based sanitizer, on porcine rotavirus strain OSU adhering to the leaf epicuticular surfaces of high- and low-wax-content cultivars. The disinfection efficacy of the oxidant-based sanitizer was affected by the surface properties of the vegetables, while the surfactant-based sanitizer was effective for both high- and low-wax leafy vegetable cultivars. This study suggests that the surface properties of vegetables may be an important factor that interacts with disinfection with food sanitizers of rotaviruses adhering to fresh produce.

Effect of cadmium accumulation on mineral nutrient levels in vegetable crops: potential implications for human health

Consumption of vegetables is often the predominant route whereby humans are exposed to the toxic metal Cd. Health impacts arising from Cd consumption may be influenced by changes in the mineral nutrient content of vegetables, which may occur when plants are exposed to Cd. Here, we subjected model root (carrot) and leaf (lettuce) vegetables to soil Cd concentrations of 0.3, 1.5, 3.3, and 9.6 μg g(-1) for 10 weeks to investigate the effect of Cd exposure on Cd accumulation, growth performance, and mineral nutrient homeostasis. The findings demonstrated that Cd accumulation in lettuce (20.1-71.5 μg g(-1)) was higher than that in carrot (3.2-27.5 μg g(-1)), and accumulation exceeded the maximum permissible Cd concentration in vegetables when soil contained more than 3.3 μg g(-1) of Cd. There was a marked hormetic effect on carrot growth at a soil Cd concentration of 3.3 μg g(-1), but increasing the Cd concentration to 9.6 μg g(-1) caused decreased growth in both crops. Additionally, in most cases, there was a positive correlation between Cd and the mineral nutrient content of vegetables, which was due to physiological changes in the plants causing increased uptake and/or translocation. This may suggest a general mechanism whereby the plant compensated for disrupted mineral nutrient metabolism by increasing nutrient supply to its tissues. Increased nutrient levels could potentially offset some risks posed to humans by increased Cd levels in crops, and we therefore suggest that changes in mineral nutrient levels should be included more widely in the risk assessment of potentially toxic metal contamination. Graphical abstract The Cd concentration (μg g-1 in dry matter) in the root, shoot and translocation factor (TF) of Cd from root to shoot in the carrot and lettuce, and the percentage of root Cd to the gross Cd contents (%) in carrot (C) and lettuce (D) exposed to soil Cd (0 (control), 1, 3, and 9 μg g-1) for 70 days. Values are means ± SD (n = 5).

Variations in the fate and biological effects of sulfamethoxazole, norfloxacin and doxycycline in different vegetable-soil systems following manure application

The fate of sulfamethoxazole (SMZ), norfloxacin (NOR) and doxycycline (DOX) and their biological effects in radish and pakchoi culture systems were investigated. DOX dissipated more rapidly than SMZ and NOR, while radish and pakchoi cultivation increased the removal of residual DOX in soils. Dissipation of NOR was accelerated in radish soils but was slowed down slightly in pakchoi soils. Vegetable cultivation exerted an insignificant effect on SMZ removal. Investigation of antibiotic bioaccumulation showed that the uptake of DOX by radish and pakchoi was undetectable, but the radish accumulated more SMZ and NOR than pakchoi. Among the three antibiotics, only SMZ use exhibited an apparent suspension of plant seed germination, up-ground plant growth and soil microbial diversity. Pakchoi responded more sensitively to SMZ than did the radish. Principal component analysis (PCA) based on MicroRESP™ indicated that the sampling time and antibiotic treatments could influence the soil microbial community. Only in the pakchoi soils did antibiotic application exert a more robust effect on the microbial community than the sampling time; SMZ treatments and DOX treatments could be clearly discriminated from the control treatments. These results are crucial for an assessment of the potential risks of antibiotics to culture system practices and suggest that good agricultural practices help to limit or even reduce antibiotic pollution.

Physics of Fresh Produce Safety: Role of Diffusion and Tissue Reaction in Sanitization of Leafy Green Vegetables with Liquid and Gaseous Ozone-Based Sanitizers

Produce safety has received much recent attention, with the emphasis being largely on discovery of how microbes invade produce. However, the sanitization operation deserves more attention than it has received. The ability of a sanitizer to reach the site of pathogens is a fundamental prerequisite for efficacy. This work addresses the transport processes of ozone (gaseous and liquid) sanitizer for decontamination of leafy greens. The liquid sanitizer was ineffective against Escherichia coli K-12 in situations where air bubbles may be trapped within cavities. A model was developed for diffusion of sanitizer into the interior of produce. The reaction rate of ozone with the surface of a lettuce leaf was determined experimentally and was used in a numerical simulation to evaluate ozone concentrations within the produce and to determine the time required to reach different locations. For aqueous ozone, the penetration depth was limited to several millimeters by ozone self-decomposition due to the significant time required for diffusion. In contrast, gaseous sanitizer was able to reach a depth of 100 mm in several minutes without depletion in the absence of reaction with surfaces. However, when the ozone gas reacted with the produce surface, gas concentration was significantly affected. Simulation data were validated experimentally by measuring ozone concentrations at the bottom of a cylinder made of lettuce leaf. The microbiological test confirmed the relationship between ozone transport, its self-decomposition, reaction with surrounding materials, and the degree of inactivation of E. coli K-12. Our study shows that decontamination of fresh produce, through direct contact with the sanitizer, is more feasible with gaseous than with aqueous sanitizers. Therefore, sanitization during a high-speed washing process is effective only for decontaminating the wash water.

Espresso coffee residues as a nitrogen amendment for small-scale vegetable production

BACKGROUND

Espresso coffee grounds constitute a residue which is produced daily in considerable amounts, and is often pointed out as being potentially interesting for plant nutrition. Two experiments (incubations and field experiments) were carried out to evaluate the potential nitrogen (N) and phosphorus (P) supply for carrot (Daucus carota L.), spinach (Spinacea oleracea L.) and lettuce (Lactuca sativa L.) nutrition.

RESULTS

Immobilisation of nitrogen and phosphorus was detected in all the incubations and, in the field experiments, germination and yield growth were decreased by the presence of espresso coffee grounds, in general for all the species studied.

CONCLUSION

The study showed an inhibition of N and P mineralisation and a reduction of plant germination and growth. Further research is required to determine whether this is related to the immobilising capacity of the residue or possibly due to the presence of caffeine.

Variations in the natural ¹⁵N abundance of Brassica chinensis grown in uncultivated soil affected by different nitrogen fertilizers

To further investigate the method of using δ(15)N as a marker for organic vegetable discrimination, the effects of different fertilizers on the δ(15)N in different growing stages of Brassica chinensis (B. chinensis) grown in uncultivated soil were investigated with a pot experiment. B. chinensis was planted with uncultivated soil and different fertilizer treatments and then harvested three times in three seasons consecutively. For the spring experiments in the years of 2011 and 2012, the δ(15)N value of B. chinensis, which increased due to organic manure application and decreased due to chemical fertilizer application, was significantly different (p < 0.05) with manure treatment and chemical treatment. The δ(15)N value of vegetables varied among three growing stages and ranged from +8.6‰ to +11.5‰ for the control, from +8.6‰ to +12.8‰ for the compost chicken manure treatment, from +2.8‰ to +7.7‰ for the chemical fertilizer urea treatment, and from +7.7‰ to +10.9‰ for the compost-chemical fertilizer treatment. However, the δ(15)N values observed in the autumn experiment of 2011 without any fertilizer application increased ranging from +13.4‰ to +15.4‰, + 11.2‰ to +17.7‰, +10.7‰ to +17.1‰, and +10.6‰ to +19.1‰, respectively, for the same treatments mentioned above. This result was not significantly different between manure treatment and chemical treatment. The δ(15)N values of soil obtained in the spring of 2011 during three growing stages were slightly affected by fertilizers and varied in the range of +1.6‰ to +2.5‰ for CK, +4.7‰ to +6.5‰ for compost treatment, +2.1‰ to +2.4‰ for chemical treatment, and +2.7‰ to +4.6‰ for chemical-compost treatment, respectively. High δ(15)N values of B. chinensis were observed in these experiments, which would be useful to supplement a δ(15)N database for discriminating organic vegetables. Although there was a significant difference between manure treatment and chemical treatment, it was still difficult to discriminate whether a labeled organic vegetable was really grown without chemical fertilizer just with a fixed high δ(15)N value, especially for the vegetables planted simultaneously with chemical and compost fertilizer.

Treated wastewater irrigation: uptake of pharmaceutical and personal care products by common vegetables under field conditions

Global water shortage is placing an unprecedented pressure on water supplies. Treated wastewater is a valuable water resource, but its reuse for agricultural irrigation faces a roadblock: the public concern over the potential accumulation of contaminants of emerging concern (CECs) into human diet. In the present study, we measured the levels of 19 commonly occurring pharmaceutical and personal care products (PPCPs) in 8 vegetables irrigated with treated wastewater under field conditions. Tertiary treated wastewater without or with a fortification of each PPCP at 250 ng/L, was used to irrigate crops until harvest. Plant samples at premature and mature stages were collected. Analysis of edible tissues showed a detection frequency of 64% and 91% in all vegetables from the treated wastewater and fortified water treatments, respectively. The edible samples from the two treatments contained the same PPCPs, including caffeine, meprobamate, primidone, DEET, carbamazepine, dilantin, naproxen, and triclosan. The total concentrations of PPCPs detected in edible tissues from the treated wastewater and fortified irrigation treatments were in the range of 0.01-3.87 and 0.15-7.3 ng/g (dry weight), respectively. Annual exposure of PPCPs from the consumption of mature vegetables irrigated with the fortified water was estimated to be only 3.69 μg per capita. Results from the present study showed that the accumulation of PPCPs in vegetables irrigated with treated wastewater was likely limited under field conditions.

Food safety and bioavailability evaluations of four vegetables grown in the highly arsenic-contaminated soils on the Guandu Plain of northern Taiwan

Arsenic contamination in a large area of agricultural fields on the Guandu Plain of northern Taiwan was confirmed in a survey conducted in 2006, but research concerning the relationship between bioavailable As concentrations in contaminated soils and crop production in Taiwan is not available. Pot experiments were conducted to examine the growth and accumulation of As in four vegetable crops grown in As-contaminated soils and to assess As intake through consumption. The phytotoxic effects of As in soils were not shown in the pot experiments in which vegetable crops were grown in soils contaminated with different As levels in situ collected from Guandu Plain (120–460 mg/kg) or artificially spiked As-contaminated soils (50–170 mg/kg). Experimental results showed that the bioavailable As extracted with 5 M NaHCO₃ from soils can be used to estimate As concentrations in vegetables. The As concentrations in the vegetables were compared with data shown in the literature and As limits calculated from drinking water standards and the provisional tolerance weekly intake (PTWI) of inorganic As established by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO). Although the As levels in the vegetables were not high and the bioavailability of As in the soils was quite low, long-term consumption may result in higher As intake in the human body.

Petroleum contamination of soil and water, and their effects on vegetables by statistically analyzing entire data set

Aliphatic hydrocarbons have been used to assess total oil concentrations, petroleum sources, and petroleum degradation. In this study, surface soil, groundwater, surface water, and vegetables were collected from the outskirts of Xi'an, the largest city in northwestern China, and the samples were analyzed for aliphatic hydrocarbon contents. The concentrations of n-alkanes were 1.06-4.01 μg/g in the soil. The concentrations and the geochemical characteristics of n-alkanes showed that the low carbon number hydrocarbons were mainly from petroleum sources, whereas the high carbon number hydrocarbons received more hydrocarbons from herbaceous plants. The concentrations of n-alkanes were 9.20-93.44 μg/L and 23.74-118.27 μg/L in the groundwater and the surface water, respectively. The water had characteristics of petroleum and submerged/floating macrophytes and was found in concentrations that would cause chronic disruption of sensitive organisms. The concentrations and geochemical characteristics of n-alkanes in Brassica chinensis L. and Apium graveolens were different, but both were contaminated by petroleum hydrocarbons. The results from principal component analysis (PCA) indicated that the sorption of n-alkanes to soil particles could not be described by linear models. The distributions of n-alkanes in vegetables were positively correlated with those in soil, and the correlation coefficient was up to 0.9310 using the constructed vectors. Therefore, the researchers should pay close attention to the effect of soil contamination on vegetables.

Roxarsone and its metabolites in chicken manure significantly enhance the uptake of As species by vegetables

Roxarsone is an organoarsenic feed additive which can be finally degraded to other higher toxic metabolites after excreted by animal. In this work, the uptake of As species by vegetables treated with chicken manure bearing roxarsone and its metabolites was investigated. It was showed that more than 96% of roxarsone added in chicken feed was degraded and converted to arsenite, monomethylarsonic acid, dimethylarsinic acid, arsenate, 4-hydroxyphenylarsonic acid and other unknown As species. Arsenite and arsenate could be found in roots of vegetables but only arsenite transported up to shoots. Chicken manure bearing roxarsone and its metabolites increased 33-175% of arsenite and 28% ∼ seven times of arsenate in vegetable roots, 68-175% of arsenite in edible vegetable shoots. Arsenite, the most toxic As form, was the major extractable As species in vegetables accounted for 79-98%. The results reflected that toxic element As could be absorbed by vegetables via the way: roxarsone in feed → animal → animal manure → soil → crop and the uptake of As species would be enhanced by using chicken manure bearing roxarsone and its metabolites as organic fertilizer.

[Combined stress of enhanced UV-B radiation and 1,2,4-trichlorobenzene contamination on the growth of green vegetable]

A pot experiment was conducted to study the effects of UV-B radiation enhancement alone, 1,2,4-trichlorobenzene (TCB) contamination soil alone, and the combined stress on the growing process, stomatal resistance and leaf structure of green vegetable. The results showed that 1,2,4-TCB contamination alone had more significant inhibitory effect on the growth of green vegetable than the combined stress. Both UV-B radiation enhancement and 1,2,4-TCB contamination reduced the stomatal resistance of front and reverse leaves. Enhanced UV-B radiation resulted in the albino of leaves. 1,2,4-TCB contamination resulted in the fading of leaf color and the appearing of black spots on leaf surfaces, and the enhanced UV-B radiation strengthened the black-spot symptom. In conclusion, the effects of UV-B radiation enhancement alone, 1,2,4-trichlorobenzene (TCB) contamination soil alone and the combined stress on the growth indicators of green vegetable were different.

Plant latex: a promising antifungal agent for post harvest disease control

Bioactive compounds from plant latex are potential source of antifungic against post harvest pathogens. Latex from a total of seven plant species was investigated for its phytochemical and antifungal properties. Six fungi namely Aspergillus fumigatus, A. niger, A. terreus, F. solani, P. digitatum and R. arrhizus were isolated from infected fruits and vegetables and tested against various solvent extracts of latex. Analysis of latex extracts with phytochemical tests showed the presence of alkaloids, flavonoids, glycosides, phenols, saponins, steroids, tannins and terpenoids. Antifungal assay revealed the potential inhibitory activity of petroleum ether extracts against the postharvest fungal isolates. Various degree of sensitivity was observed irrespective of plant species studied with A. terreus and P. digitatum as the most susceptible ones. F. solani and A. fumigatus were moderately sensitive to the latex extracts tested. Among the plants, latex of Thevetia peruviana (75.2%) and Artocarpus heterophyllus (64.8%) were having potential antifungal activity against the isolates followed by Manilkara zapota (51.1%). In conclusion, use of plant latex makes interest to control postharvest fungal diseases and is fitting well with the concept of safety for human health and environment.

Arsenic contamination in the food chain and its risk assessment of populations residing in the Mekong River basin of Cambodia

In the present study, we investigated the potential arsenic exposure of Cambodian residents from their daily food consumption. Environmental and ecological samples such as paddy soils, paddy rice (unhusked), staple rice (uncooked and cooked), fish and vegetables were collected from Kandal, Kratie and Kampong Cham provinces in the Mekong River basin of Cambodia. After acid-digestion, digestates were chemically analyzed by inductively coupled plasma mass spectrometry. Results revealed that the means of total arsenic concentration ([As]tot) in paddy soils and paddy rice from Kandal were significantly higher than those from Kampong Cham province (t-test, p<0.05). Moreover, a significant positive correlation between the [As]tot in paddy soils and paddy rice was found (r(14) = 0.826, p<0.01). Calculations of arsenic intake from food consumption indicated that the upper end of the range of the daily dose of inorganic arsenic for Kandal residents (0.089-8.386 μg d(-1) kg(-1) body wt.) was greater than the lower limits on the benchmark dose for a 0.5% increased incidence of lung cancer (BMDL0.5 is equal to 3.0 μg d(-1) kg(-1) body wt.). The present study suggests that the residents in Kandal are at risk of arsenic intake from their daily food consumption. However, the residents in Kratie and Kampong Cham provinces are less likely to be exposed to arsenic through their daily dietary intake. To the best of our knowledge, this is the first report estimating the daily intake and daily dose of inorganic arsenic from food consumption in the Mekong River basin of Cambodia.

[Production of inhibiting plant growth and development hormones by pathogenic for legumes Pseudomonas genus bacteria]

It has been studied the ability of pathogenic for legumes pathovars of Pseudomonas genus to produce ethylene and abscisic acid in vitro. A direct correlation between the level of ethylene production by agent of bacterial pea burn--Pseudomonas syringae pv. pisi and level of its aggressiveness for plants has been found. It is shown that the amount of abscisic acid synthesized by pathogenic for legumes Pseudomonas genus bacteria correlates with their aggressiveness for plants.

Risk assessment of vegetables irrigated with arsenic-contaminated water

Arsenic (As) contaminated water is used in South Asian countries to irrigate food crops, but the subsequent uptake of As by vegetables and associated human health risk is poorly understood. We used a pot trial to determine the As uptake of four vegetable species (carrot, radish, spinach and tomato) with As irrigation levels ranging from 50 to 1000 μg L(-1) and two irrigation techniques, non-flooded (70% field capacity for all studied vegetables), and flooded (110% field capacity initially followed by aerobic till next irrigation) for carrot and spinach only. Only the 1000 μg As L(-1) treatment showed a significant increase of As concentration in the vegetables over all other treatments (P < 0.05). The distribution of As in vegetable tissues was species dependent; As was mainly found in the roots of tomato and spinach, but accumulated in the leaves and skin of root crops. There was a higher concentration of As in the vegetables grown under flood irrigation relative to non-flood irrigation. The trend of As bioaccumulation was spinach > tomato > radish > carrot. The As concentration in spinach leaves exceeded the Chinese maximum permissible concentration for inorganic As (0.05 μg g(-1) fresh weight) by a factor of 1.6 to 6.4 times. No other vegetables recorded an As concentration that exceeded this threshold. The USEPA parameters hazard quotient and cancer risk were calculated for adults and adolescents. A hazard quotient value greater than 1 and a cancer risk value above the highest target value of 10(-4) confirms potential risk to humans from ingestion of spinach leaves. In our study, spinach presents a direct risk to human health where flood irrigated with water containing an arsenic concentration greater than 50 μg As L(-1).

Home gardening near a mining site in an arsenic-endemic region of Arizona: assessing arsenic exposure dose and risk via ingestion of home garden vegetables, soils, and water

The human-health risk posed by gardening near a legacy mine and smelter in an arsenic-endemic region of Arizona was characterized in this study. Residential soils were used in a greenhouse study to grow common vegetables, and local residents, after training, collected soil, water, and vegetables samples from their home gardens. Concentrations of arsenic measured in water, soil, and vegetable samples were used in conjunction with reported US intake rates to calculate the daily dose, Incremental Excess Lifetime Cancer Risk (IELCR), and Hazard Quotient for arsenic. Relative arsenic intake dose decreased in order: water>garden soils>homegrown vegetables, and on average, each accounted for 77, 16, and 7% of a residential gardener's daily arsenic intake dose. The IELCR ranges for vegetables, garden soils, and water were 10(-8) to 10(-4), 10(-6) to 10(-4), and 10(-5) to 10(-2), respectively. All vegetables (greenhouse and home garden) were grouped by scientific family, and the risk posed decreased as: Asteraceae≫Fabaceae>Amaranthaceae>Liliaceae>Brassicaceae>Solanaceae≫Cucurbitaceae. Correlations observed between concentrations of arsenic in vegetables and soils were used to estimate a maximum allowable level of arsenic in soil to limit the excess cancer risk to 10(-6). The estimated values are 1.56 mg kg(-1), 5.39 mg kg(-1), 11.6 mg kg(-1) and 12.4 mg kg(-1) for the Asteraceae, Brassicaceae, Fabaceae, and Amaranthaceae families, respectively. It is recommended that home gardeners: sample their private wells annually, test their soils prior to gardening, and, if necessary, modify their gardening behavior to reduce incidental soil ingestion. This study highlights the importance of site-specific risk assessment, and the need for species-specific planting guidelines for communities.

Evaluation of antioxidant activity of leafy vegetables and beans with myoglobin method

KEY MESSAGE : Antioxidant activity of seven leafy vegetables and four beans against five reactive oxygen species and reactive nitrogen species was clearly characterized with a protocol using myoglobin as a reporter probe. Antioxidant activity of seven leafy vegetables and four beans against peroxyl radical, hydroxyl radical, hypochlorite ion, and peroxynitrite ion has been measured using myoglobin as a reporter probe (myoglobin method). Conventional DPPH method was also used to evaluate antioxidant activity of the samples. Difference of activity against different reactive oxygen species (ROS) and reactive nitrogen species (RNS) was characterized by plotting the data in a 5-axe cobweb chart. This plot clearly showed the characteristics of the antioxidant activity of the leafy vegetables and the beans. The samples examined in this work were categorized into four groups. (1) The samples showed high antioxidant activity against all ROS and RNS: daikon sprout, spinach, Qing-geng-cai, and onion. (2) The samples showed high antioxidant activity against peroxyl radical: red bean and soy bean. (3) The samples showed high antioxidant against hypochlorite ion: broccoli floret, cabbage, and Chinese cabbage. (4) The samples showed weak antioxidant activity against all ROS and RNS: cowpea and common beans. Our protocol is probably useful to characterize antioxidant activity of the crops of different cultivars, the crops obtained in different growing environments and growing seasons, the crops harvested at different age, and the crops stored in the different conditions, as well as the changes of activity during cooking process of the crops.

Composting of waste paint sludge containing melamine resin and the compost's effect on vegetable growth and soil water quality

Melamine resin (MR) is introduced to the environment from many industrial effluents, including waste paint sludge (WPS) from the automobile industry. Melamine resin contains a high nitrogen (N) content and is a potential N source during composting. In this study, two carbon sources, waste paper (WP) and plant residue (PR), were used to study their effects on composting of WPS. Additional work tested the WPS-composts effects on plant growth and soil water quality. After 84 days of composting, 85% and 54% of the initial MR was degraded in WP- and PR-composts, respectively. The limiting factor was that the MR created clumps during composting so that decomposition was slowed. Compared to the untreated control, both WP- and PR-composts increased growth of cucumber (Cucumis sativus), radish (Raphanus sativus) and lettuce (Lactuca sativa). Concentrations of trace elements in plants and soil water did not rise to a level that would preclude WPS-composts from being used as a soil amendment.