Disinfection of selected vegetables under nonthermal treatments: Chlorine, acid citric, ultraviolet light and ozone

Photodissociation-driven photoacoustic spectroscopy with UV-LEDs for ozone detection

This study presents the development and evaluation of a UV-LED based photoacoustic (PA) measurement system for ozone (O3) detection to demonstrate its potential for low-cost and accurate sensing while for the first time addressing the importance of photodissociation for PA signal generation for O3 in the UV range. With a detection limit of 7.9 ppbV, the system exhibits a significant advancement over state-of-the-art UV-PA O3 detection and is on par with laser-based setups. Following a novel discussion of the PA signal arising from photodissociation and its products, cross-sensitivity effects due to environmental factors such as temperature and gas composition were systematically analyzed. A digital twin driven compensation for these influences was implemented and evaluated. Despite the challenges associated with modeling the effects of H2O and CO2, the PA system shows considerable potential, though further studies in real world applications must be conducted.

A Review of Non-thermal Interventions in Food Processing Technologies

Foodborne pathogens and spoilage microorganisms continue to be a concern throughout the food industry. As a result, these problematic microorganisms are the cause of foodborne outbreaks, foodborne illness, and premature spoilage-related issues. To address these, thermal technologies have been applied and have a documented history of controlling these microorganisms. Although beneficial, some of these technologies may result in adverse quality effects that can interfere with consumer acceptability. Processors of fresh produce also need technologies to mitigate pathogens with the ability to retain raw quality. In addition, thermal technologies can also result in the reduction or depletion of key nutrients. Consumers of today are health conscious and are concerned with key nutrients in food products necessary for their overall health; this reduction and depletion of nutrients could be considered unacceptable in the eyes of consumers. As a result of this, the food industry works to increase the use of nonthermal technologies to control pathogens and spoilage microorganisms in varying sections of the industry. This review paper will focus on the control of foodborne pathogens and spoilage organisms along with the effects on quality in various food products by the use of pulsed electric field, pulsed light, ultraviolet light, ozonation, cold atmospheric plasma, ultrasound, and ionizing radiation.

Ultraviolet and pulsed light treatment of spices and herbs and their products: Microbial safety, enzyme inactivation, bioactive retention, and shelf-life extension

Spices and herbs are a crucial component of the global food industry, valued for their unique flavors, aromas, and bioactive properties. However, microbial contamination and quality degradation during production, storage, and distribution pose significant challenges. Ultraviolet (UV) and pulsed light (PL) processing have emerged as nonthermal technologies offering effective, eco-friendly solutions for microbial decontamination and quality retention in spices. This review explores recent advancements and applications of UV and PL treatments in the spice industry, highlighting their impact on pathogenic and spoilage microbial safety, physicochemical properties, and bioactive compound retention. UV processing, primarily involving UV-C radiation, inactivates microorganisms by disrupting DNA, offering effective surface decontamination without compromising quality of spices and herbs. PL, which utilizes high-intensity, broad-spectrum light pulses, extends this capability to irregularly shaped surfaces, further enhancing microbial inactivation. Both methods preserve key quality attributes such as phenolics, flavonoids, antioxidant activity, ascorbic acids, and color while mitigating sensory losses, making them attractive alternatives to conventional thermal and chemical treatments. The review also examines critical factors influencing the efficacy of these technologies, including processing parameters, spice morphology, and microbial load. Despite promising results, challenges related to regulatory approval, equipment design, and consumer acceptance remain. This comprehensive analysis underscores the potential of UV and PL technologies to revolutionize spices and herbs processing, ensuring safety and quality while aligning with sustainable and consumer-driven demands in the food industry.

γ-aminobutyric acid treatment inhibits browning and promotes storage quality by regulating reactive oxygen species and membrane lipid metabolism in fresh-cut stem lettuce

The effects of γ-aminobutyric (GABA) on enzymatic browning, storage quality, membrane and reactive oxygen species (ROS) metabolism in fresh-cut stem lettuce were investigated. The results illustrated that GABA treatment delayed browning degree, polyphenol oxidase (PPO) activity and the expression of LsPPO. Meanwhile, higher chlorophyll and ascorbic acid contents were exhibited in GABA-treated stem lettuce, as well as the slower microbial propagation. Further investigation revealed that exogenous GABA application declined malondialdehyde content, electrolyte leakage and the enzyme activities of membrane metabolism, and the expression levels of related genes were also downregulated. In addition, GABA treatment scavenged ROS and strengthened the enzyme activities of ROS metabolism, as well as the expression levels of corresponding genes. Taken together, these findings implied that the repressed enzymatic browning and microbial propagation in GABA-treated stem lettuce were due to the inhibition of ROS accumulation, enhancement of membrane stability and increased resistance to oxidation.

Bioaccessibility of bioactive compounds present in Persea americana Mill. seed ingredient during oral-gastric digestion with antibacterial capacity against Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

In ancient Mexican cultures, the Persea americana Mill seed has been used against gastrointestinal diseases, due to high concentrations of bioactive compounds. According to Traditional Mexican Medicine, P. americana seed aqueous infusion is used against roundworms, intestinal worms, parasites, and gastrointestinal problems, in a dose taken over three or four days. In addition, Mexican Society of Natural History indicates the traditional use of P. americana seed powder as an antiparasitic, and antibacterial. On the other hand, Helicobacter pylori infection is a factor associated with the development of gastric disease, peptic ulcers as well as some types of gastric lymphomas and gastric cancer in humans; in this way is necessary scientific evidence about P. americana seed effect in gastrointestinal disease.

AIM OF THE STUDY

The work aimed to evaluate bioactive compounds bioaccessibility and antimicrobial potential against Helicobacter pylori during oral-gastric digestion in vitro of food ingredient from Persea americana Mill. seed and elucidate the possible action mechanism using in silico tools.

MATERIALS AND METHODS

Initially, P. americana seed oil and aqueous extract of P. americana seed were obtained using ultrasound and maceration respectively, and the food ingredient from P. americana seed was obtained. The samples underwent oral-gastric digestions by the INFOGEST method, to continue identifying and quantifying the bioactive compounds by HPLC-DAD and GC-MS. The anti-Helicobacter pylori activity determination were used fourteen Helicobacter pylori clinical strains and reference strains by Susceptibility testing by Minimal Inhibition Concentration, Kinetics of Growth Inhibition of H. pylori, Urease Inhibitory Kinetic. Finally, to elucidate a possible action mechanism used in silico tools (Software AutoDock 4.2.6 and BioVia Discovery v.19.1.0.1.18287).

RESULTS

The lipophilic fraction of P. americana seed detected oleic acid, linoleic acid, and avocadenofuran compounds, and the phenolic fraction showed the presence of catechin, rutin, ellagic, and chlorogenic acid, among others. Phenolic compounds conformational changes during oral-gastric digestion due to mechanical and acid hydrolysis, while lipophilic compounds showed a 20% increase in the gastric phase. Persea americana Mill. seed ingredient (3.08 μg/mL) showed total in vitro inhibition of clinical and reference strains of H. pylori, likewise, the lipophilic fraction had a lower inhibition concentration (2.59 μg/mL) regardless of the strains. Among the mechanisms found in silico, inhibition of target proteins such as CagA, BabA, and MUC5 were observed, as virulence factors involving adherence and bacterial pathogenicity.

CONCLUSIONS

This research provides evidence that food ingredient from P. americana seed has antimicrobial in vitro potential against H. pylori clinical strains, through phenolic and mainly lipophilic compounds, opening new scientific evidence that supports the P. americana seed's traditional use.

The impact of ozone and equilibrium-modified atmosphere packaging on storage stability and health-promoting indicators of fresh "Angelino" plums

Effectiveness of ozone concentrations (2, 5, and 10 ppm) and exposure time (3 and 9 min) on selected physicochemical properties (pH, soluble solids, color values (L*, a*, and b*), and texture) and health-promoting indicators such as organic acids, total phenolics (TP), and anthocyanins of "Angelino" fresh plums was evaluated during storage (0, 30, 90, and 120 days) in equilibrium modified atmosphere packaging (EMAP). Total anthocyanin contents and organic acid profiles were significantly affected by storage times. Malic acid (MA) was the main organic acid in "Angelino" plums. MA content (4663 and 4764 mg/L) was the highest value in the ozonated 2-ppm/9-min and 5-ppm/3-min than other ozonated groups and also control at 120 days of the storage. The ozone treatments especially 2-ppm/9-min and 5-ppm/3 min can significantly retard the degradation of MA content (8294 to 2688-2694 mg/L) during the storage (p < .05). Total phenol content were most significantly decreased in the control during storage, with the loss at the level of 31.7% of TPs, while the lowest one 2-ppm/9-min (20.8%) and 5-ppm/-3 min (21.9%). The color and texture are maintained for the ozone applications compared to the control during storage. Ozonation with 2-ppm/9-min and 5-ppm/-3 min showed the best performance while maintaining the storage stability based on the physicochemical properties including hardness and bioactive compounds (such as anthocyanins and organic acids), visual appearance due to the more attractive color (L*, a*, b*) the plums.

Processing and preservation technologies to enhance indigenous food sovereignty, nutrition security and health equity in North America

Indigenous foods are carriers of traditional native North American food culture and living philosophy. They are featured by the wide varieties in fresh and processed forms, richness in nutrition, flavor, health benefits and diversity in origins, but are usually misunderstood or underrepresented in the modern food systems. Conventional processing and cooking methods are sometimes labor-intensive, less efficient and lack science-based guidelines to prevent unseen safety risks and food loss. Global and regional climate change have caused additional challenges to conventional cooking/processing, and increased native communities' reliance on externally produced foods, which have resulted in increasing nutritional unbalance and prevalence of diet-related health issues. Current and emerging technologies, such as storage and packaging, drying, safety processing, canning, pickling, and fermentation, which treat foods under optimized conditions to improve the safety and extend the shelf-life, are increasingly used in current food systems. Therefore, exploring these technologies for indigenous foods offers opportunities to better preserve their nutrition, safety, and accessibility, and is critical for the sovereignty and independence of indigenous food systems, and sustainability of indigenous food culture. This mini-review focuses on identifying adoptable processing and preservation technologies for selected traditional indigenous foods in North America, summarizing education, extension, and outreach resources and discussing the current challenges and future needs critical to expanding knowledge about indigenous foods and improving food sovereignty, nutrition security, and health equity.

The Use of Ultraviolet Irradiation to Improve the Efficacy of Acids That Are Generally Recognized as Safe for Disinfecting Fresh Produce in the Ready-to-Eat Stage

Fresh-cut produce is usually produced under standardized disinfection processes, which are unavailable at the ready-to-eat stage. Currently, chemical sanitizers are used for washing, but their disinfection efficacy is limited. In this study, UV-C (1.03 kJ/m2) was combined with organic acids that are generally recognized as safe (GRAS), including citric, malic, acetic, and lactic acids (LAs), to wash lettuce and cherry tomatoes that are contaminated with Escherichia coli O157:H7 and Salmonella Typhimurium. The results showed that LA was the most effective treatment among the single treatments, with a pathogen reduction and cross-contamination incidence of 2.0-2.3 log CFU/g and 28-35%, respectively. After combining with UV-C, the disinfection efficacy and cross-contamination prevention capacity of the four GRAS acids significantly improved. Among the combination treatments, the highest pathogen reduction (2.5-2.7 log CFU/g) and the lowest cross-contamination incidence (11-15%) were achieved by LA-UV. The analyses of ascorbic acid, chlorophyll, lycopene, antioxidant capacity, and ΔE indicated that neither the single nor combination treatments negatively affected the quality properties. These results provide a potential hurdle technology for fresh produce safety improvement at the ready-to-eat stage.

Minimizing Escherichia coli O157:H7 contamination in indoor farming: effects of cultivar type and ultra-violet light quality

BACKGROUND

Bacterial contamination of produce is a concern in indoor farming due to close plant spacing, recycling irrigation, warm temperatures, and high relative humidity during production. Cultivars that inherently resist contamination and photo-sanitization using ultraviolet (UV) radiation during the production phase can reduce bacterial contamination. However, there is limited information to support their use in indoor farming.

RESULTS

Lettuce (Lactuca sativa) cultivars with varying plant architectures grown in a custom-built indoor farm exhibited differences in E. coli O157:H7 survival after inoculation. The survival of E. coli O157:H7 was lowest in the leaf cultivar (open architecture) and highest in the romaine and oakleaf cultivars (compact architecture). Of the different UV wavelengths that were tested (UV-A, UV-A + B, UV-A + C), UV A + C at an intensity of 54.5 μmol m-2 s-1 (with 3.5 μmol m-2 s-1 of UV-C), provided for 15 min every day, was found to be most efficacious in reducing the E. coli O157:H7 survival on romaine lettuce with no negative effects on plant growth and quality.

CONCLUSION

Contamination of E. coli O157:H7 on lettuce plants can be reduced and the food safety levels in indoor farms can be increased by selecting cultivars with an open leaf architecture coupled with photo-sanitization using low and frequent exposure to UV A + C radiation. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Combined antibacterial effect of 460 nm light-emitting diode illumination and chitosan against Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes on fresh-cut melon, and the impact of combined treatment on fruit quality

This study evaluated the combined antibacterial effect of 460 nm LED illumination and chitosan on Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes on fresh-cut melon surface and its impact on the quality of melon at a total dose of 2.4 kJ/cm2 at 4 and 10 °C. Results showed that the antibacterial effect of LED illumination in combination with chitosan (0.5 and 1.0%) was much better than that of LED illumination alone, showing their synergistic effect. Among the pathogens, L. monocytogenes was the most susceptible pathogen to LED illumination. Although the color of melons became paler after LED illumination, there was little to no change in ascorbic acid content, total flavonoid content, or antioxidant capacity of the illuminated fruits compared with non-illuminated fruits. Thus, these results suggest that chitosan-mediated 460 nm LED illumination could be applied to inactivate foodborne pathogens on fresh-cut melons during storage at food establishments.

Evaluation of the Effectiveness of Aeration and Chlorination during Washing to Reduce E. coli O157:H7, Salmonella enterica, and L. innocua on Cucumbers and Bell Peppers

The attachment strength of bacteria to surfaces can affect the efficacy of sanitizers during washing. This study aimed to determine the effectiveness of chlorination and aeration in the removal of pathogens from the surface of produce. Cucumbers and bell peppers were inoculated with Listeria innocua, Escherichia coli O157:H7, or Salmonella enterica; afterwards, the produce was washed with or without chlorinated water (100 ppm) for 3 min in combination with or without aeration. Cucumbers washed with chlorinated water, with or without aeration, presented significant reductions of L. innocua (3.65 log CFU/cm2 and 1.13 log CFU/cm2, respectively) (p < 0.05). Similarly, bell peppers washed in chlorinated water with aeration (1.91 log CFU/g) and without aeration (2.49 log CFU/g) presented significant reductions of L. innocua. A significant reduction of L. innocua was observed on bell peppers washed with non-chlorinated water with aeration (2.49 log CFU/g) (p < 0.05). Non-chlorinated water was also effective in significantly reducing the level of Salmonella enterica (p < 0.05) on cucumbers and bell peppers. Washing with chlorinated water with aeration reduced Salmonella enterica levels from 4.45 log CFU/cm2 on cucumbers to below the detectable limit (0.16 log CFU/cm2). The highest reduction of Salmonella enterica from bell peppers occurred after washing with chlorinated water with aeration (2.48 log CFU/g). E. coli O157:H7, L. innocua, and Salmonella enterica levels present in non-chlorinated water after washing contaminated produce with or without aeration were significantly greater than those in chlorinated water (p < 0.05). After treatment, the population levels of all pathogens in chlorinated water with or without aeration were below the detectable limit for bell peppers (<1.10 log CFU/mL) and cucumbers (<1.20 log CFU/mL). Using chlorine in combination with forced aeration during washing minimizes cross-contamination of bacterial pathogens.

Citric Acid: Properties, Microbial Production, and Applications in Industries

Citric acid finds broad applications in various industrial sectors, such as the pharmaceutical, food, chemical, and cosmetic industries. The bioproduction of citric acid uses various microorganisms, but the most commonly employed ones are filamentous fungi such as Aspergillus niger and yeast Yarrowia lipolytica. This article presents a literature review on the properties of citric acid, the microorganisms and substrates used, different fermentation techniques, its industrial utilization, and the global citric acid market. This review emphasizes that there is still much to explore, both in terms of production process techniques and emerging new applications of citric acid.

Effect of peeling, cutting, or shredding of lettuce, carrot, or potato on the efficacy of chlorine disinfection

Minimally processed vegetables are washed and subsequently disinfected by immersion in water solutions with antimicrobials which reduce the initial pathogenic or spoilage microbial load. Chlorine remains one of the most widely used disinfectants for vegetables and hence the importance of studying its properties. The aim of this study was to evaluate the effect of peeling, cutting, and shredding on the effectiveness of chlorine (200 ppm) as a disinfectant in lettuce, carrot, and potato. Three independent repetitions of each experiment were completed, and data was statistically analyzed. Results showed that the maintenance of the chlorine concentration in the disinfectant solution, over time, depended on the vegetables' preliminary processing technique (whole, peeled, cut, or shredded) (p < 0.05). In general, the disinfection treatments studied reduced Escherichia coli by 1-8 logs. The addition of chlorine in the disinfectant solution allowed greater reduction in E. coli than using water immersions (p < 0.05) and disinfection times longer than 5 min did not improve these microbiological reductions (p>0.05). The vegetables' subdivision (whole, peeled, cut, or shredded) can affect both E coli's reduction and the vegetables' residual chlorine concentration. No trend was observed in terms of sensory differences and their relationship to the vegetables' processing and disinfection. These results suggest that each facility must validate its disinfection processes, according to the conditions established on site and reduction goals related to initial microbial counts, vegetables' quality, processing operations, and other important aspects.

Aqueous Ozone Efficacy for Inactivation of Foodborne Pathogens on Vegetables Used in Raw Meat-Based Diets for Companion Animals

The present study evaluates the efficacy of a batch wash ozone sanitation system (BWOSS) and spray wash ozone sanitation system (SWOSS) against Listeria monocytogenes (two strains) and Salmonella enterica subsp. enterica (three serovars) inoculated on the surface of carrots, sweet potatoes, and butternut squash, commonly used in raw meat-based diets (RMBDs) marketed for companion animals such as dogs and cats. Produce either remained at room temperature for 2 h or were frozen at -20°C and then tempered overnight at 4°C to mimic the preprocessing steps of a raw pet food processing operation ('freeze-temper') prior to ozone treatment. Two ozone concentrations (0 and 5 ppm) were applied for either 20 s or 60 s for BWOSS and 20 s for SWOSS. Based on an ANOVA, BWOSS data showed no significant difference (P > 0.05) in microbial reduction between 0 and 5 ppm ozone concentration across all treatment durations for each produce type. BWOSS resulted in mean microbial reductions of up to 1.56 log CFU/mL depending on the treatment time and produce type. SWOSS data were analyzed using a generalized linear model with Quasipoisson errors. Freeze-tempered produce treated with SWOSS had a higher bacterial log reduction at 5 ppm ozone compared to 0 ppm ozone (P = 0.0013) whereas room temperature produce treated with SWOSS did not show any significant difference in microbial reduction between ozone concentrations. The potential to mitigate microbial cross-contamination was also investigated during SWOSS treatment. The results indicate that 5 ppm ozone decreased pathogens in the rinsate and proximal surfaces by 0.63-1.66 log CFU/mL greater than no ozone depending on the pathogen and sample. Overall, data from this study indicate that SWOSS would be more effective compared to BWOSS in reducing the microbial load present on the surface of root tubers and squash subjected to freezing and thawing and has the potential to mitigate cross-contamination within RMDB manufacturing environments.

Biogenic silver nanoparticles and cinnamaldehyde as an effective sanitizer for fresh sweet grape tomatoes

This study evaluated the antibacterial activity of cinnamaldehyde (CIN) and biogenic silver nanoparticles (BioAgNP), alone and in combination, against Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus in vitro. Their sanitation activities on fresh sweet grape tomatoes were also evaluated. CIN and BioAgNP inhibited the growth of the tested bacteria, and at low concentrations, their combinations presented a synergistic effect. In the sanitization of fresh sweet grape tomatoes, CIN (156 µg/mL) combined with BioAgNP (31.25 µM) at subinhibitory concentrations inhibited the growth of E. coli after only 5 min of contact. Exposed samples showed no growth of E. coli during their shelf life. The combination of these compounds did not change significantly (p > 0.05) the physicochemical properties of sweet grape tomatoes and showed that CIN combined with BioAgNP could represent an effective method for decontaminating fruits and vegetables. This combination has great potential for application in the prevention of foodborne diseases.

Effects of pH, Total Soluble Solids, and Pectin Concentration on Color, Texture, Vitamin C, and Sensory Quality of Mango Fruit Bar

Mango purée is a byproduct of the current production processes (such as freeze-drying, dehydration) after the product shaping stage or grades II and III mangoes. Currently, fruit bar is a convenient and highly nutritious snack made from fruit. The objective of this study is to utilize mango byproduct in order to develop a fruit bar processing technology, which is based on evaluating the quality (color, break force, vitamin C content, and sensory) when varying the pH of mango purée and the concentration of added pectin. Additionally, total soluble solids (TSS) after blending at 80°C were also investigated. The increase in pH, pectin concentration of mango purée, and TSS after blending showed that vitamin C content in fruit bars tended to decrease. TSS results revealed that at TSS = 63°Bx, pH 3.3, and a pectin concentration of 1.3%, the product received a high rating of 6.3. Additionally, the vitamin C content of the product reached 7.82 mg/100 gDW. The results of this study are expected on the diversification of products from mango. Solving the situation that grades II and III mangoes are difficult to be commercialized and making the most of the byproduct mango flesh after certain production processes.

Carvacrol-loaded nanoemulsions produced with a natural emulsifier for lettuce sanitization

Carvacrol is an antimicrobial agent that shows potential for eliminating microorganisms in vegetables, increasing food safety. However, intense odor and low water solubility of carvacrol are limiting factors for its application for fresh vegetables sanitization, which can be overcome by nanotechnology. Two different nanoemulsions containing carvacrol (11 mg/mL) were developed by probe sonication: carvacrol-saponin nanoemulsion (CNS) and carvacrol-polysorbate 80 nanoemulsion (CNP). Formulations presented appropriate droplet sizes (from 74.7 nm to 168.2 nm) and high carvacrol encapsulation efficiency (EE) (from 89.5 % to 91.5 %). CNS showed adequate droplet size distribution (PDI < 0.22) and high zeta potential values (around -30 mV) compared to CNP, with saponin chosen for the following experiments. Carvacrol nanoemulsions presented Bacterial Inactivation Concentration (BIC) against the Salmonella cocktail from 5.51 to 0.69 mg/mL and for the E. coli cocktail from 1.84 to 0.69 mg/mL. Among all tested nanoemulsions, CNS1 presented the lowest BIC (0.69 mg/mL) against both bacterial cocktails. Damage to bacterial cells in lettuce treated with nanoemulsion was confirmed by scanning electron microscopy. For lettuce sanitization, CNS1 showed a similar effect to unencapsulated carvacrol, with a high bacterial reduction (>3 log CFU/g) after lettuce immersion for 15 min at 2 × BIC. Using the same immersion time, the CNS1 (2 × BIC) demonstrated equal or better efficacy in reducing both tested bacterial cocktails (>3 log CFU/g) when compared to acetic acid (6.25 mg/mL), citric acid (25 mg/mL), and sodium hypochlorite solution (150 ppm). Lettuce immersed in CNS1 at both concentrations (BIC and 2 × BIC) did not change the color and texture of leaves, while the unencapsulated carvacrol at 2 × BIC darkened them and reduced their firmness. Consequently, carvacrol-saponin nanoemulsion (CNS1) proved to be a potential sanitizer for lettuce.

Effects of chlorine and peroxyacetic acid wash treatments on growth kinetics of Salmonella in fresh-cut lettuce

Fresh-cut produces are often consumed uncooked, thus proper sanitation is essential for preventing cross contamination. The reduction and subsequent growth of Salmonella enterica sv Thompson were studied in pre-cut iceberg lettuce washed with simulated wash water (SWW), sodium hypochlorite (SH, free chlorine 25 mg/L), and peroxyacetic acid (PAA, 80 mg/L) and stored for 9 days under modified atmosphere at 9, 13, and 18 °C. Differences in reduction between SH and PAA were non-existent. Overall, visual quality, dehydration, leaf edge and superficial browning and aroma during storage at 9 °C were similar among treatments, but negative effects increased with temperature. These results demonstrated that PAA can be used as an effective alternative to chlorine for the disinfection of Salmonella spp. in fresh-cut lettuce. The growth of Salmonella enterica sv Thompson was successfully described with the Baranyi and Roberts growth model in the studied storage temperature range, and after treatment with SWW, chlorine, and PAA. Subsequently, predictive secondary models were used to describe the relationship between growth rates and temperature based on the models' family described by Bělehrádek. Interestingly, the exposure to disinfectants biased growth kinetics of Salmonella during storage. Below 12 °C, growth rates in lettuce treated with disinfectant (0.010-0.011 log CFU/h at 9 °C) were lower than those in lettuce washed with water (0.016 log CFU/h at 9 °C); whereas at higher temperatures, the effect was the opposite. Thus, in this case, the growth rate values registered at 18 °C for lettuce treated with disinfectant were 0.048-0.054 log CFU/h compared to a value of 0.038 log CFU/h for lettuce treated with only water. The data and models developed in this study will be crucial to describing the wash-related dynamics of Salmonella in a risk assessment framework applied to fresh-cut produce, providing more complete and accurate risk estimates.

Changes in phenolics and flavonoids in amaranth and soybean sprouts after UV-C treatment

Sprouts, mainly from cereals, legumes, and some pseudo-cereals, are rich in nutrients and contain biocompounds, making them attractive for consumption. This research study aimed to develop treatments with UV-C light in soybean and amaranth sprouts and evaluate their effect on biocompounds content, compared with chlorine treatments. UV-C treatments were applied at distances of 3 and 5 cm and times of 2.5, 5, 10, 15, 20, and 30 min, whereas chlorine treatments were applied as immersion in solutions at 100 and 200 ppm for 15 min. Phenolics and flavonoid content were higher in UV-C-treated sprouts than in those treated with chlorine solutions. Ten biocompounds were identified in soybean sprouts, with increasing in apigenin C-glucoside-rhamnoside (105%), apigenin 7-O-glucosylglucoside (237%), and apigenin C-glucoside malonylated (70%) due to UV-C application (3 cm, 15 min); for amaranth sprouts, five biocompounds were identified, with higher contents of p-coumaroylquinic acid (17.7%) after UV-C treatment (3 cm, 15 min). The best treatment to achieve the highest bioactive compounds concentration was UV-C at a distance of 3 cm for 15 min, without significant modification on the color parameters, Hue and chroma. PRACTICAL APPLICATION: UV-C can be used to increase the biocompound content in amaranth and soybean sprouts. Nowadays, there is UV-C equipment available for industrial applications. In this way, sprouts may be maintained as fresh through this physical technology, and they will retain or increase the concentration of health-related compounds.

Chitosan enhances antibacterial efficacy of 405 nm light-emitting diode illumination against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp. on fresh-cut melon

This study aimed to evaluate the influence of chitosan on the antibacterial efficacy of 405 nm LED illumination against Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes on fresh-cut melons. The antibacterial efficacy of LED illumination (a total dose of 1.3 kJ/cm²) with or without chitosan (0.5 and 1.0 %) against these three pathogens was determined at 4 and 10 °C, respectively. Non-illuminated and chitosan-treated fruits were stored in the dark for 36 h under the same temperature. Color changes, ascorbic acid content, and total flavonoid content of illuminated and non-illuminated fruits were also analyzed. The results showed that the populations of all three pathogens on the non-illuminated and chitosan-treated fruits remained unchanged during storage. Regardless of bacterial species and chitosan concentrations, LED illumination in combination with chitosan greatly reduced the bacterial populations by 1.5 - 3.5 log/cm², which was greater than LED illumination alone. Among the three pathogens, L. monocytogenes was the most susceptible to chitosan-mediated LED illumination. However, the whiteness index of illuminated fruits significantly increased by 1.3-fold compared to that of non-illuminated fruits, regardless of the presence of chitosan. Unlike color, no significant difference was observed in ascorbic acid and total flavonoid contents between illuminated and non-illuminated fruits. Although the fruit color was changed by LED illumination, these results indicate that adding chitosan could enhance the antibacterial efficacy of 405 nm LED illumination against major foodborne pathogens on fresh-cut melons without changing nutritional quality.

Development of benchmark datasets for text mining and sentiment analysis to accelerate regulatory literature review

In the field of regulatory science, reviewing literature is an essential and important step, which most of the time is conducted by manually reading hundreds of articles. Although this process is highly time-consuming and labor-intensive, most output of this process is not well transformed into machine-readable format. The limited availability of data has largely constrained the artificial intelligence (AI) system development to facilitate this literature reviewing in the regulatory process. In the past decade, AI has revolutionized the area of text mining as many deep learning approaches have been developed to search, annotate, and classify relevant documents. After the great advancement of AI algorithms, a lack of high-quality data instead of the algorithms has recently become the bottleneck of AI system development. Herein, we constructed two large benchmark datasets, Chlorine Efficacy dataset (CHE) and Chlorine Safety dataset (CHS), under a regulatory scenario that sought to assess the antiseptic efficacy and toxicity of chlorine. For each dataset, ∼10,000 scientific articles were initially collected, manually reviewed, and their relevance to the review task were labeled. To ensure high data quality, each paper was labeled by a consensus among multiple experienced reviewers. The overall relevance rate was 27.21% (2,663 of 9,788) for CHE and 7.50% (761 of 10,153) for CHS, respectively. Furthermore, the relevant articles were categorized into five subgroups based on the focus of their content. Next, we developed an attention-based classification language model using these two datasets. The proposed classification model yielded 0.857 and 0.908 of Area Under the Curve (AUC) for CHE and CHS dataset, respectively. This performance was significantly better than permutation test (p < 10E-9), demonstrating that the labeling processes were valid. To conclude, our datasets can be used as benchmark to develop AI systems, which can further facilitate the literature review process in regulatory science.

Effect of Anolyte on S. Typhimurium and L. monocytogenes Growth in Minced Pork and Beef Cuts

In this paper, anolyte is considered as a possible disinfectant for inhibiting the growth of bacteria in meat (beef cuts and minced pork). Meat cuts were contaminated with two concentrations of L. monocytogenes and S. Typhimurium, as these are the most common meat pathogens that are closely regulated by the EU, and treated with two different concentrations of anolyte: 20% for beef cuts and 18% for minced pork. Then, the total viable count (TVC), L. monocytogenes count and S. Typhimurium count were determined. In meat cuts and minced pork, anolyte was able to reduce TVC, S. Typhimurium and L. monocytogenes counts effectively, significantly decreasing L. monocytogenes and S. Typhimurium counts after spraying and throughout 29 days of incubation at 0-4 °C. TVC was reduced after spraying and for 10 days of incubation but later increased to be the same as before spraying with anolyte. Anolyte was effective when spraying beef cuts with a 20% solution for 60 s against pathogenic bacteria L. monocytogenes and Salmonella spp. and also when using it at a concentration of 18% from the minced meat mass. Initially, anolyte significantly decreased TVC, however during the storage period (10-29 days) TVC increased but remained significantly lower compared to control. Anolyte was effective in reducing L. monocytogenes and S. Typhimurium counts throughout the study, and after 29 days of incubation, these bacteria could not be detected in the samples treated with anolyte.

Synergistic inactivation of Escherichia coli O157:H7 and Staphylococcus aureus by gallic acid and thymol and its potential application on fresh-cut tomatoes

Antibacterial activity against Escherichia coli O157:H7 and Staphylococcus aureus of five typical plant-derived compounds [gallic acid (G.A), citral (Cit), thymol (Thy), salicylic acid (S.A), lauric acid (L.A)] were investigated by determining the minimum inhibitory concentration (MIC) and the fractional inhibitory concentration index (FICI). The results showed that only a combination of Thy and G.A (TGA), with a concentration of 0.1 and 1.25 mg/mL, respectively, had a synergistic effect (FICI = 0.5) on both E. coli O157:H7 and S. aureus. The amount of Thy and G.A in mixture were four-fold lower than the MICs of the individuals shown to cause the equivalent antimicrobial activity in trypticase soy broth (TSB). The microbial reduction obtained in TSB with addition of TGA were significantly higher (P < 0.05) than the reduction shown for the broth supplemented with the separated phenolics. TGA caused the changes of morphology and membrane integrity of bacteria. Additionally, the application of TGA on fresh-cut tomatoes are investigated. Fresh-cut tomatoes inoculated with E. coli O157:H7and S. aureus were washed for 2min, 5min, 10min at 4 °C, 25 °C, 40 °C in 0.3% NaOCl, or water containing TGA at various concentrations. Overall, the reduction of TGA achieved against S. aureus is higher than E. coli O157:H7. Same concentrations of combined antimicrobials at a temperature of 40 °C further increased the degree of microbial inactivation, with an additional 0.89-1.51 log CFU/g reduction compared to that at 25 °C. Moreover, 1/2MIC_Thy+1/2MIC_G.A at 25 °C for 10min or 40 °C for 5min were generally acceptable with sensorial scores higher than 7. Our results showed that TGA could work synergistically on the inactivation of the tested bacteria and may be used as an alternative disinfectant of fresh produce.

Combination of ozone and ultrasonic-assisted aerosolization sanitizer as a sanitizing process to disinfect fresh-cut lettuce

Reduction of sanitizer dosage and development of non-immersion disinfection methods have become major focuses of research. Here, we examined the disinfection efficacy of combining gaseous ozone (4 and 8 ppm) with aerosolized oxidizing sanitizer [sodium hypochlorite (SH, 100 and 200 ppm)] and aerosolized organic acid [acetic acid (AA, 1% and 2%) and lactic acid (LA, 1% and 2%)]. Notably, 1% AA and 4 ppm gaseous ozone were ineffective for disinfecting Salmonella Typhimurium, and treatment with 1% AA + 8 ppm ozone caused browning of lettuce leaves and stimulated increases in aerobic mesophilic count (AMC), aerobic psychrotrophic count (APC), S. Typhimurium, and Escherichia coli O157:H7. Treatment with 2% LA + 8 ppm ozone resulted in the lowest S. Typhimurium, E. coli O157:H7, Listeria monocytogenes, AMC, APC, and molds and yeasts during storage (0-7 days at 4 °C). Quality analysis indicates that LA + 8 ppm ozone and SH + 8 ppm ozone did not negatively affect L*, a*, b*, polyphenolic content, weight loss, and sensory properties; however, the levels of two individual phenolic compounds (3,4-dihydroxybenzoic acid and vanillin), responsible for phenylpropanoid synthesis, were significantly increased after treatment with 2% LA + 8 ppm ozone. These findings provided insights into the use of LA combined with gaseous ozone for application in disinfecting fresh produce.

Ozone Treatments for Preserving Fresh Vegetables Quality: A Critical Review

Ozone is recognized as an antimicrobial agent for vegetables storage, washing, and processing. This strong disinfectant is now being used in the food industry. In this review, the chemical and physical properties of ozone, its generation, and factors affecting ozone processing efficiency were explained as well as recent regulatory developments in the food industry. By then selecting three vegetables, we show that ozone avoids and controls biological growth on vegetables, keeping their attractive appearance and sensorial qualities, assuring nutritional characteristics' retention and maintaining and increasing the shelf-life. In liquid solution, ozone can be used to disinfect processing water and vegetables, and in gaseous form, ozone helps to sanitize and preserve vegetables during storage. The multifunctionality of ozone makes it a promising food processing agent. However, if ozone is improperly used, it causes some deleterious effects on products, such as losses in their sensory quality. For an effective and a safe use of ozone, specific treatment conditions should be determined for all kinds of vegetables. In a last step, we propose highlighting the different essential characteristics of ozone treatment in order to internationally harmonize the data relating to the treatments carried-out.

Antimicrobial activity of 405 nm light-emitting diode (LED) in the presence of riboflavin against Listeria monocytogenes on the surface of smoked salmon

This study investigated the antimicrobial activity of 405 nm light-emitting diode (LED) with and without riboflavin against Listeria monocytogenes in phosphate buffered saline (PBS) and on smoked salmon at different storage temperatures and evaluated its impact on food quality. The results show that riboflavin-mediated LED illumination in PBS 25 °C significantly inactivated L. monocytogenes cells by 6.2 log CFU/mL at 19.2 J/cm², while illumination alone reduced 1.9 log CFU/mL of L. monocytogenes populations at 57.6 J/cm². L. monocytogenes populations on illuminated smoked salmon decreased by 1.0-2.2 log CFU/cm² at 1.27-2.76 kJ/cm² at 4, 12, and 25 °C, regardless of the presence of riboflavin. Although illumination with and without riboflavin caused the lipid peroxidation and color change in smoked salmon, this study demonstrates the potential of a 405 nm LED to preserve the smoked salmon products, reducing the risk of listeriosis.

A Review on Individual and Combination Technologies of UV-C Radiation and Ultrasound in Postharvest Handling of Fruits and Vegetables

Ultraviolet-C radiation and ultrasound technology are widely accepted and continuously being appraised as alternatives to conventional thermal techniques for decontamination of fruits and vegetables. However, studies in these areas have presented challenges related to quality, safety, limited capability, and cost of energy. This review paper presents an up-to-date summary of applications of ultraviolet-C radiation and ultrasound technology for postharvest handling of fruits and vegetables from relevant literature. The limitations associated with applications of ultraviolet-C radiation and ultrasound technology individually has prompted their combination alongside other antimicrobial strategies for enhanced bactericidal effect. The combination of ultraviolet-C radiation and ultrasound technology as a hurdle approach also provides enhanced efficiency, cost effectiveness, and reduced processing time without compromising quality. The review includes further scope of industrial-led collaboration and commercialization of ultraviolet-C radiation and ultrasound technology such as scale-up studies and process optimization.

Sonozonation: Enhancing the antimicrobial efficiency of aqueous ozone washing techniques on cherry tomato

Ultrasound requires high power and longer treatment times to inactivate microorganisms when compared to ultrasound combined with other technologies. Also, the antimicrobial efficiency of aqueous ozone increases with an increase in its concentration and exposure time, but with a detrimental effect on the quality of the treated food. In this study, the effect of aqueous ozone at low concentration, multi-mode frequency irradiation and their combination on microbial safety and nutritional quality of cherry tomato was investigated. Individual washing with aqueous ozone and mono-mode frequency irradiation resulted in <1 log CFU/g reduction in the spoilage microorganisms, while dual-mode frequency irradiation (DMFI) resulted in higher microbial reduction (1.3-2.6 1 log CFU/g). The combined system (20/40 kHz + aqueous ozone) on the other hand, resulted in >3 log CFU/g microbial reduction. The application of DMFI enhanced the antimicrobial efficiency of aqueous ozone without any detrimental effect on the physicochemical properties (except the firmness), bioactive compounds, and antioxidants of the cherry tomato during 21 days refrigerated storage. The result obtained indicates the promising substitute to the single washing technique for microbial safety as well as preserving the nutritional quality and enhancing the shelf life of cherry tomato.

Current and future perspectives for controlling Vibrio biofilms in the seafood industry: a comprehensive review

The contamination of seafood with Vibrio species can have severe repercussions in the seafood industry. Vibrio species can form mature biofilms and persist on the surface of several seafoods such as crabs, oysters, mussels, and shrimp, for extended duration. Several conventional approaches have been employed to inhibit the growth of planktonic cells and prevent the formation of Vibrio biofilms. Since Vibrio biofilms are mostly resistant to these control measures, novel alternative methods need to be urgently developed. In this review, we propose environmentally friendly approaches to suppress Vibrio biofilm formation using a hypothesized mechanism of action.

Chlorine gas is an effective alternative to sterilize carnation leaves for Fusarium spp. identification

Sterile carnation leaves are required for proper morphological identification of Fusarium spp. but the gamma irradiation equipment required for leaf sterilization is not available to everyone. This study evaluated three different methods for sterilizing carnation leaves: microwave radiation, ultraviolet, and chlorine gas (CG) sterilization. Both microwave and ultraviolet treatments did not sufficiently sterilize leaf tissue, however, exposure to CG for 2 h resulted in no growth of either fungi or bacteria. Exposure times of carnation leaves to CG were also evaluated for spore production, spore size and morphological characteristics of five Fusarium spp. Only carnation leaves exposed to CG for 45, 60 or 90 min were completely free of microorganism contamination. There were some differences in spore production and size, however, no differences were observed for characteristics essential for proper species identification such as micro- and macrospore features and production of sporodochia, perithecia, chlamydospores, and phialides for any of the CG exposure times. This study identified leaves sterilized by CG as a reliable substitute for gamma irradiation sterilization. The method described here is suitable for most laboratories and will provide a means for Fusarium identification when gamma irradiated leaves are not available.

Efeitos da radiação UV-C em alface e maçã minimamente processadas: uma revisão

Resumo A alta procura por alimentos nutritivos e de fácil consumo tem impulsionado o mercado de frutas e hortaliças minimamente processadas (MP). No entanto, estes alimentos têm uma curta vida de prateleira, são marcados pela rápida deterioração. A radiação ultravioleta-C (UV-C) é uma técnica não térmica, limpa e de baixo custo que pode servir como alternativa aos sanitizantes comuns. Porém, a sua baixa penetração em alimentos tem limitado sua aplicação neste ramo da indústria. Objetivou-se revisar o efeito germicida da radiação UV-C em alface e maçã minimamente processados e os possíveis danos às características físicas e sensoriais, além de realizar uma avaliação dos fatores envolvidos nesta técnica. Uma redução de 1 a 2 log UFC/g da microflora natural destes vegetais é facilmente atingida com doses moderadas, para diversos grupos de microrganismos deteriorantes. Uma maior redução nos níveis de patogênicos inoculados, acima de 4 log UFC/g, foi verificada quando doses maiores foram utilizadas. Para a alface MP, a superfície irregular é considerada um limitante, por reduzir o contato entre a radiação e os microrganismos. Essa limitação pode ser superada alterando parâmetros do processo, como distância da fonte emissora e exposição de ambos os lados do vegetal. A cor das folhas foi melhor preservada com emprego de radiação UV-C em doses moderadas. Na maçã MP, alterações indesejáveis, como a intensa perda de massa e o escurecimento pronunciado, estão associadas a um severo dano celular em doses mais elevadas. Tais efeitos puderam ser evitados expondo a fruta por um menor tempo. Em geral, verificou-se boa aceitabilidade de alface e maçã MP tratadas com radiação UV-C. O tipo de fruta ou hortaliça utilizado e a sua topografia exercem grande influência na eficiência da técnica. Não foi possível sugerir uma dosagem adequada para a alface ou a maçã MP, visto que os poucos estudos disponíveis diferem quanto à variedade de alface ou maçã estudada, na forma como os tratamentos foram conduzidos e na dose exposta.

Effect of Ozone Treatment on Flavonoid Accumulation of Satsuma Mandarin (Citrus unshiu Marc.) during Ambient Storage

This study aimed to compare the flavonoid accumulation between ozone-treated and untreated Satsuma mandarin (Citrusunshiu Marc.) fruits. The fruits exposed to gaseous ozone were found to have higher antioxidant activities and content of flavonoid during the storage period by ultra-high performance liquid chromatography (UPLC). To reveal the molecular regulation of flavonoid accumulation by ozone, chalcone synthase (CHS), chalcone isomerase (CHI), β-1,3-glucanase (GLU), chitinase (CHT), phenylalanine ammonia-lyase (PAL), and peroxidase (POD) were identified and their expression was examined by quantitative real-time polymerase chain reaction (q-PCR). These results support the promising application of ozone treatment as a safe food preservation technique for controlling postharvest disease and extending shelf-life of harvested Satsuma mandarin.

Evaluating a Combined Method of UV and Washing for Sanitizing Blueberries, Tomatoes, Strawberries, Baby Spinach, and Lettuce

We assessed a fresh produce decontamination system using a combined method of UV and washing (water-assisted UV [WUV]) in different scales. The system used tap water to wash fresh produce while exposing it to UV light. First, the reduction of Salmonella in tap water under UV treatment (1 to 1,740 mJ/cm2) was determined. Increasing the UV dose significantly (P < 0.05) increased the Salmonella reduction in wash water, and UV intensity of more than 2 mW/cm2 could reduce Salmonella in tap water to below 1 CFU/mL given enough processing time (more than 1 min; UV dose of 120 mJ/cm2). Then, the decontamination effectiveness of a small WUV system was tested on blueberries (50 g). Blueberries were spot or dip inoculated with a Salmonella cocktail and treated by the small WUV system (200 mL of water). In general, WUV treatments achieved significantly better Salmonella inactivation than tap water wash; tap water wash (10 min) and 2 mW/cm2 WUV treatment (with a UV dose of 1,200 mJ/cm2) reduced populations of spot-inoculated Salmonella on blueberries by 2.44 and 5.45 log, respectively. Compared with spot-inoculated Salmonella on blueberries, dip-inoculated Salmonella was more difficult to be inactivated by WUV treatments. Then, the decontamination effectiveness of WUV treatments was tested on blueberries (170 g), tomatoes (290 g), strawberries (170 g), baby spinach (60 g), and lettuce (60 g) using a larger WUV system. In general, 10 min of 29 mW/cm2 WUV treatment (a high UV dose of 17,400 mJ/cm2) resulted in significantly better Salmonella inactivation than tap water wash (for 10 min) regardless the inoculation method, agreeing with the results of the small-scale study. For both spot- and dip-inoculated lettuce, no significant difference (P > 0.05) in Salmonella inactivation by WUV treatments was observed when the quantity of lettuce increased from 50 to 100 g.

Antimicrobial action of octanoic acid against Escherichia coli O157:H7 during washing of baby spinach and grape tomatoes

We investigated the antimicrobial efficacy of octanoic acid (OA) against Escherichia coli O157:H7 inoculated on the surface of baby spinach and grape tomatoes during simulated washing processes. 3 mM OA at 45 °C achieved >6 log CFU/g reduction from the surface of tomatoes within 2 min. However, washing baby spinach with 6 mM OA at 5 °C resulted in <1 log CFU/g reduction, highlighting the role of surface properties in inactivation efficacy. OA significantly (p < 0.05) reduced the risk of cross-contamination during washing of spinach as well as tomatoes. Also, total mold and yeast population on surface of spinach was significantly reduced immediately after OA wash and inhibited during following 14 days. Baby spinach and grape tomatoes washed with OA did not cause significant (p > 0.05) difference in color compared to the control and no residual OA was detected in most cases following rinsing of produce in water. OA at the concentrations above 2 mM and temperature higher than 25 °C induced severe membrane damage along with release of ATP and other intracellular constituents resulting in bacterial death. OA can be an attractive natural decontamination agent for washing fresh produce.