Dissipation of pesticides during bread-making

Development of a processing factor prediction model for pesticides in processed tomato foods using elastic net regularization

A novel regularized elastic net regression model was developed to predict processing factor (PF) for pesticide residues, which represents a change in the residue levels during food processing. The PF values for tomato juice, wet pomace and dry pomace in the evaluations and reports published by the Joint FAO/WHO Meeting on Pesticide Residues significantly correlated with the physicochemical properties of pesticides, and subsequently the correlation was observed in the present tomato processing study. The elastic net regression model predicted the PF values using the physicochemical properties as predictor variables for both training and test data within a 2-fold range for 80-100% of the pesticides tested in the tomato processing study while overcoming multicollinearity. These results suggest that the PF values are predictable at a certain degree of accuracy from the unique sets of physicochemical properties of pesticides using the developed model based on a processing study with representative pesticides.

Residue Behavior of Chiral Fungicide Prothioconazole and Its Major Chiral Metabolite in Flour Product Processing

This study systematically investigates the stereoselective metabolism and residue behavior of chiral pesticide prothioconazole enantiomers during the steaming, baking, and frying of steamed buns, bread, and deep-fried dough sticks. The results show that steaming, baking, and frying can significantly promote the degradation of the prothioconazole enantiomers. In low- and high-concentration treatments, the degradation rates of prothioconazole enantiomers were over 96.0% and 45.4%, respectively, and the residual concentration of prothioconazole-desthio enantiomers was less than 32.7 μg/kg (excluding fried processing). During the processing of steamed buns, bread, and deep-fried dough sticks, the enantiomer fraction (EF) value of the prothioconazole enantiomer was close to 0.5, and the stereoselectivity was not significant. During the processing of steamed buns (low concentration), bread (low and high concentrations), and deep-fried dough sticks (low concentration), the stereoselectivity of prothioconazole-desthio was significant, and preferential enantiomer degradation occurred. Following the analysis of 120 flour product samples, the residual risk.

Current-use pesticide exposure pathways in Czech adults and children from the CELSPAC-SPECIMEn cohort

INTRODUCTION

In this study, we aimed to characterise exposure to pyrethroids, organophosphates, and tebuconazole through multiple pathways in 110 parent-child pairs participating in the CELSPAC-SPECIMEn study.

METHODS

First, we estimated the daily intake (EDI) of pesticides based on measured urinary metabolites. Second, we compared EDI with estimated pesticide intake from food. We used multiple linear regression to identify the main predictors of urinary pesticide concentrations. We also assessed the relationship between urinary pesticide concentrations and organic and non-organic food consumption while controlling for a range of factors. Finally, we employed a model to estimate inhalation and dermal exposure due to spray drift and volatilization after assuming pesticide application in crop fields.

RESULTS

EDI was often higher in children in comparison to adults, especially in the winter season. A comparison of food intake estimates and EDI suggested diet as a critical pathway of tebuconazole exposure, less so in the case of organophosphates. Regression models showed that consumption per g of peaches/apricots was associated with an increase of 0.37% CI [0.23% to 0.51%] in urinary tebuconazole metabolite concentrations. Consumption of white bread was associated with an increase of 0.21% CI [0.08% to 0.35%], and consumption of organic strawberries was inversely associated (-61.52% CI [-79.34% to -28.32%]), with urinary pyrethroid metabolite concentrations. Inhalation and dermal exposure seemed to represent a relatively small contribution to pesticide exposure as compared to dietary intake.

CONCLUSION

In our study population, findings indicate diet plays a significant role in exposure to the analysed pesticides. We found an influence of potential exposure due to spray drift and volatilization among the subpopulation residing near presumably sprayed crop fields to be minimal in comparison. However, the lack of data indicating actual spraying occurred during the critical 24-hour period prior to urine sample collection could be a significant contributing factor.

Distribution, migration and changes of typical chemical preservatives on orange during storage and processing

To evaluate the safety of orange treated with preservatives, we analyzed the distribution, migration and changes of the three most common preservatives (prochloraz, imazalil, and thiophanate-methyl) during orange storage and processing. After treatment, preservatives entered orange rapidly within 2 h, and with the greatest levels being in the outer yellow peel, followed by the stem, middle white peel, and finally pulp. The intra-fruit migration ability of the three preservatives correlated inversely with their octanol/water partition coefficients. Residual preservatives and their metabolites in orange pulp were less than 0.84 mg/kg in storage duration. Orange juice and pectin processing could effectively remove the residues, with processing factors (PFs) of 0.159-0.446 and 0.014-0.059. For tangerine peel, however, the process increased the levels of residual preservatives with PFs of 2.964-6.004. Therefore, concern is warranted with regard to the risk of dietary exposure to tangerine peel and essential oil.

Impact of technological processes on tebuconazole reduction in selected cereal species and the primary cereal product, and dietary exposure assessment

Contamination of cereals with tebuconazole (TEB) can affect the dietary risk assessment. This study investigates, for the first time, how mechanical, thermal, physical-chemical, and biochemical processes affect the TEB level in wheat, rye, and barley. The biochemical process of malting was the most effective for tebuconazole reduction (by 86%) in cereals. Thermal processes were also effective, i.e., boiling (70%) and baking (55%). These processes considerably decreased the concentration of tebuconazole, and Procesing Factors (PFs) were from 0.10 to 0.18 (malting), 0.56 to 0.89 (boiling), and 0.44 to 0.45 (baking), respectively. The concentration of TEB was not reduced after the application of mechanical processing. The risk was estimated in dietary exposure assessment on the basis of the highest reported levels of tebuconazole residues bread. At a high level of rye bread consumption, the potential exposure to tebuconazole reached only 3.5% and 2.7% in children and adults, respectively.

Microbial Detoxification of Residual Pesticides in Fermented Foods: Current Status and Prospects

The treatment of agricultural areas with pesticides is an indispensable approach to improve crop yields and cannot be avoided in the coming decades. At the same time, significant amounts of pesticides remain in food and their ingestion causes serious damage such as neurological, gastrointestinal, and allergic reactions; cancer; and even death. However, during the fermentation processing of foods, residual amounts of pesticides are significantly reduced thanks to enzymatic degradation by the starter and accompanying microflora. This review concentrates on foods with the highest levels of pesticide residues, such as milk, yogurt, fermented vegetables (pickles, kimchi, and olives), fruit juices, grains, sourdough, and wines. The focus is on the molecular mechanisms of pesticide degradation due to the presence of specific microbial species. They contain a unique genetic pool that confers an appropriate enzymological profile to act as pesticide detoxifiers. The prospects of developing more effective biodetoxification strategies by engaging probiotic lactic acid bacteria are also discussed.

Degradation and chiral properties of metamifop during rice processing

Metamifop has been used to control gramineous weeds in paddy fields and may form residues in rice. In this study, the residue analysis method for metamifop and the metabolites was set up based on high-performance liquid chromatography-mass spectrometry and the chiral analysis method was also developed. The enantioselective degradation and residue of metamifop in rice processing were studied, and the major metabolites were monitored. The removal rate of metamifop by washing could reach 60.03%, while the loss in rice and porridge cooking was less than 16%. No decrease was found in fermentation into fermented grains, but metamifop was degraded in the process of rice wine fermentation with half-lives of around 9.5 days. N-(2-fluorophenyl)-2-(4-hydroxyphenoxy)-N-methylpropionamide and 6-chlorobenzo [d] oxazole-2 (3H)-one were found to be the major metabolites. This study reveals the enantioselective residue of metamifop in rice processing, which helps understand the potential risk in food consumption.

Effect of Chinese steamed bun and bread processing on pesticide residues in wheat flour

The changes of five pesticides including imidacloprid, triadimefon, fenitrothion, chlorpyrifos-methyl, and chlorpyrifos in wheat flour during Chinese steamed bun and bread processing were systematically investigated. The pesticide residues were determined by high performance liquid chromatography coupled with diode array detector. Dough mixing step in both Chinese steamed bun and bread processing reduced the concentration of five pesticide residues significantly by 33 to 46%. It was mainly attributed to the increase of moisture content in mixed dough during this step. The reduction of pesticides in fermenting step varied from 2 to 22% in Chinese steamed bun and bread processing. Resting step in both Chinese steamed bun and bread processing has little effect on the pesticide residues with the reduction from 2 to 8%. The five pesticides have different behaviours in steaming step of Chinese steamed bun processing and in baking step of bread processing. During the steaming step, only the concentrations of triadimefon and imidacloprid residues in crust were increased by 52 and 1%, the others in crust and in crumb of Chinese steamed bun were decreased by 4 to 38%. After the baking step, the concentrations of triadimefon and imidacloprid residues in crust, and the triadimefon residue in crumb of bread were increased by 65, 83, and 14%, respectively, the others were all reduced. The processing factors (PFs) for triadimefon and imidacloprid in crust in the steaming and baking steps, for triadimefon in crumb in the baking steps were greater than 1, and the others were all less than 1. Overall, this study provides important references for monitoring pesticide residues in the processing of wheat flour products. The PFs obtained could be helpful for the risk assessment of pesticides in wheat flour products.

Degradation of pesticides in wheat flour during noodle production and storage

The fate of five pesticides comprising triadimefon, imidacloprid, fenitrothion, chlorpyrifos-methyl, and chlorpyrifos in wheat flour during noodle production and accelerated storage was systematically investigated. Pesticide residues were determined by high-performance liquid chromatography with diode array detection (HPLC-DAD) after each processing step and accelerated storage. The results indicated that dough mixing reduced the concentration of five pesticide residues by 23-42%, mainly owing to the increase of moisture content. Dough resting had little effect on the residues of triadimefon, imidacloprid, and fenitrothion, but decreased chlorpyrifos-methyl and chlorpyrifos significantly by 24% and 15%, respectively. The pesticide residues increased by 3% to 69% during the drying step, attributed to the different role played by thermal evaporation or thermal degradation and concentration of the different pesticides. Boiling lowered the pesticide residues significantly by 56% to 74% in both fresh noodles and dried noodles. All the pesticide residues decreased during accelerated storage, especially for fenitrothion, chlorpyrifos-methyl, and chlorpyrifos. The processing factors (PFs) of the five pesticides in the drying step were greater than 1, while the others were all less than 1. The whole process for noodle production was beneficial to reduce the pesticide residues with PFs ranging from 0.15 to 0.35. The PFs of five pesticides in accelerated storage were all below 1.

Fate of chlorpyrifos, omethoate, cypermethrin, and deltamethrin during wheat milling and Chinese steamed bread processing

To investigate the fractioning of chlorpyrifos, omethoate, cypermethrin, and deltamethrin during wheat milling and the fate of four pesticides during Chinese steamed bread (CSB) processing, wheat samples, which were sprayed twice with chlorpyrifos, omethoate, cypermethrin, and deltamethrin at three levels of concentrations during the grain-filling stage, were milled, and wheat flour was processed to CSB. The residues of four pesticides in the milling products, kneaded dough, fermented dough, and CSB were determined with GC-MS/MS. The concentrations of chlorpyrifos, omethoate, cypermethrin, and deltamethrin in bran were 1.46-1.57, 1.85-2.13, 1.27-1.86, and 1.63-2.33 times higher than those in wheat, respectively, while the residues of the four pesticides in shorts decreased approximately 27.97% to 57.02% for chlorpyrifos, 6.22% to 44.77% for cypermethrin, and 13.13% to 61.15% for deltamethrin compared with the residues in wheat (p < .05); however, omethoate levels approximately doubled in the ten-fold treatment group in shorts compared with those in wheat (p < .05). The residues of the four pesticides in flour were significantly lower than those in wheat, ranging from 38.68% to 98.04%. Chlorpyrifos and omethoate levels showed a slight decrease during the kneading and fermentation process, and further decreases of 2.46%-29.51% for chlorpyrifos and 14.22%-71.11% for omethoate were found in CSB; however, most of the groups of cypermethrin and deltamethrin showed various degrees of increases in kneaded and fermented dough and steamed bread compared with flour. The mechanism of this increase is unknown and needs further research.

Degradation Trends of Some Insecticides and Microbial Changes during Sauerkraut Fermentation under Laboratory Conditions

The aim of this study was to monitor the degradation of three insecticides licensed for the control of cabbage moths during the 14-day fermentation period of sauerkraut samples. The hypothesis of this study is that the different sauerkraut fermentation processes could affect the degradation of applied insecticides. For this purpose, the fresh cabbage leaves contaminated with (λ-cyhalothrin, malathion, and chlorpyrifos-methyl) were left for fermentation with and without (natural) starter addition (Lactobacillus plantarum 112), and vacuum-packed as a control under laboratory conditions. The pH values and microbial growth were periodically monitored in sauerkraut samples during the fermentation period. During this time, the insecticide residues were determined in control and treatment samples using LC-MS-MS. In control samples, the degradation of chlorpyrifos-methyl and malathion was higher with rates of 69 and 98%, respectively, compared with the sauerkraut samples (12 and 59%; 31 and 34%, respectively) 14 days after the insecticide application. At the end of fermentation (14 d), no significant reduction in λ-cyhalothrin was detected in both treatments and control (13-19% reduction). The current study demonstrated that the presence of the lactic acid bacteria in the sauerkraut fermentation accelerated pH decline (below 4.0), and these fermentation conditions probably decelerated the degradation of malathion and chlorpyrifos-methyl. The results showed that the stability of different insecticides varied during the same fermentation process.

Stereoselective behaviors of the fungicide triadimefon and its metabolite triadimenol during malt storage and beer brewing

The stereoselective behaviors of triadimefon (TF) and its metabolite triadimenol (TN) during barley storage and beer brewing were studied by supercritical fluid chromatography-tandem mass spectrometry to shed light on potential security risks. Matrix-matched calibration curves were constructed for barley and beer, with determination coefficients (r²) ≥ 0.9991. Average recoveries of 77.2-107.5 % and relative standard deviations within 15.0 % were observed. The degradation of the TF enantiomers during storage followed pseudo-first-order kinetics, and S-TF was degraded in preference to R-TF with the half-life ranges 18.5-36.5 d and 20.4-69.3 d, respectively. During beer brewing, the TF enantiomers (enantiomer fraction, 0.44-0.56) were selectively metabolized into TN stereoisomers (diastereomer fraction, 0.43-0.58). The total pesticide content of beer was 93.3 % lower than that of raw grain, whereby the TF content declined by up to 100 % and the TN stereoisomers were reduced by 35.1 %. The processing factors of all the brewing steps were less than one, illustrating that beer consumption is safer after its commercial processing. Furthermore, the TF enantiomers showed different behaviors upon fermentation by two yeast strains. Thus, this work is a useful reference for assessing the food safety risk posed by individual pesticide enantiomers and their contribution to environmental pollution.

Fate of Residual Pesticides in Fruit and Vegetable Waste (FVW) Processing

Plants need to be protected against pests and diseases, so as to assure an adequate production, and therefore to contribute to food security. However, some of the used pesticides are harmful compounds, and thus the right balance between the need to increase food production with the need to ensure the safety of people, food and the environment must be struck. In particular, when dealing with fruit and vegetable wastes, their content in agrochemicals should be monitored, especially in peel and skins, and eventually minimized before or during further processing to separate or concentrate bioactive compounds from it. The general objective of this review is to investigate initial levels of pesticide residues and their potential reduction through further processing for some of the most contaminated fruit and vegetable wastes. Focus will be placed on extraction and drying processes being amid the main processing steps used in the recuperation of bioactive compounds from fruit and vegetable wastes.

Processing factors of pesticide residues in biscuits and their relation to the physicochemical properties of pesticides

Agricultural commodities are generally consumed as processed food. Therefore, it is indispensable to assess pesticide residues in processed products rather than only in the raw agricultural commodity, in order to approach a more realistic scenario of dietary exposure. Processing factors are important tools for dietary exposure risk assessments. In this study, processing factors for the baking process were derived for 41 pesticides in cereal bran-based biscuits. The raw materials used consisted of wheat, rye, oat, and barley grains with incurred pesticides, which originally was produced for test material for European Union Proficiency Tests. Information on physicochemical properties of pesticides was collected for understanding the fate of pesticides during the baking process. Average processing factors varied between 0.67 and 1.6. Most pesticide residues exhibited a reduction of pesticide residues of less than 24%, which correspond to a processing factor (PF) range between 1 and 0.76, showing resistance to the baking process. However, for polar compounds such as carbendazim and volatile compounds (chlorpyrifos-methyl, malathion, and pirimiphos-methyl) larger reduction rates were observed, up to 33% (PF: 0.67). In general, a prolonged baking time did not significantly affect the PF, because the main degradation process takes place within the first 6 min. However, this was not the case for the highly volatile compounds, highly polar compounds, and compounds of low degradation temperature. These latter were significantly reduced with prolonged baking time, resulting in a reduction rate of up to 95%, which means an almost complete elimination.

Simulation Study for the Degradation of Some Insecticides during Different Black Table Olive Processes

The aim of this study was to determine the effects of different olive processing methods on deltamethrin (DEL), dimethoate (DIM), and imidacloprid (IMI), the most commonly preferred synthetic insecticides for controlling olive pests such as the olive fruit fly. The hypothesis is that the fermentation could accelerate the degradation process of the insecticides. For this purpose, olives were left for fermentation (natural black olives) without and with starter addition (two Lactobacillus plantarum strains 112 and 123) and processed as dehydrated black olives. To monitor the degradation rate of insecticides, olives were first polluted with the insecticides and then the residues were detected periodically during the processes. The insecticide degradation rates were found to be significantly higher in natural black olives and natural black olives inoculated with both starters compared with those of crude olives and dehydrated black olives. At the end of fermentation (after 60 d), 53-61% of deltamethrin, 66-68% of dimethoate, and 42-50% of imidacloprid were removed in natural black olives and natural black olives inoculated with both starters. In dehydrated olives, the degradation of deltamethrin, dimethoate, and imidacloprid was lower with rates of 9.7, 40, and 13.4%, respectively. The current study demonstrated that natural and starter-added natural black olive processing accelerated the degradation of deltamethrin, dimethoate, and imidacloprid.

Persistence of tetraniliprole and reduction in its residues by various culinary practices in tomato in India

A field experiment was conducted to study the persistence and dissipation pattern of a new molecule tetraniliprole on tomato fruits and soil. Tetraniliprole was sprayed at the rate of 60 g a.i. ha^-1 and 120 g a.i. ha^-1on the tomato crop. Tomato fruit samples were analyzed as per the method described by Bosta and Nageswara (Asian J Res Chem 8:383-388, 2015). The residues of tetraniliprole and its metabolite chinazolinon were estimated on HPLC equipped with RP C₁₈ column and photo diode array detector. Initial deposits of tetraniliprole were 0.865 and 1.747 mg kg^-1 on fruits and 0.092 and 0.177 mg kg^-1 in the soil, respectively, from the two treatments at the rate 60 g a.i. ha^-1 and 120 g a.i. ha^-1. The residues on fruits dissipated to half in 2.7 and 3.49 days, respectively. Based on the persistence studies, a waiting period of 15 days is suggested on tomato fruit from consumer's safety point of view. The pesticide residues, left to a variable extent in the tomato after harvesting, are beyond the control of consumers and have deleterious effects on human health; hence, their residues reduction by various culinary processes were highlighted. Treated tomato fruit samples collected at 1, 3, and 5 days after application were also subjected to common household practices. Washing of tomato fruits by tap, lukewarm, and saline water reduce tetraniliprole residues up to 37.63, 44.67, and 61.49%, respectively. Microwave cooking of tomato provided >12% better relief from tetraniliprole residues in comparison with open pan cooking of 72.21%. Chinazolinon residues, a metabolite of tetraniliprole, were not detected in any analyzed processed tomato fruit sample.

Reduction of pesticide residues from teff (Eragrostis tef) flour spiked with selected pesticides using household food processing steps

Teff (Eragrostis tef) is an ancient cereal that is indigenous from Ethiopia. Nowadays, teff grain is becoming popular to many parts of the world. Teff is gluten-free in nature, has high iron and fiber content, and many other health benefits make this crop interesting to many consumers. Since no insect pests are attacking the teff grains, farmers do not apply pesticides on it, unlike maize and other grains. Nevertheless, residues of organochlorine pesticides have been detected at an alarming level that could pose a consumer risk. Teff is often consumed as injera which is a fermented flat pancake. The main aim of the present study is, therefore, to investigate the effect of household food processing (doughing and baking) on the reduction of pesticide residues from teff. Pesticide residues previously detected in teff grain such as permethrin, cypermethrin, deltamethrin, chlorpyrifos ethyl, p,p'-DDE, p,p'-DDD, o,p'-DDT, and p,p'-DDT were spiked and extracted followed by the subsequent household processing which are generally doughing (dough making followed by fermentation) and baking. From the findings of this study, doughing decrease the pesticide residues in the range of 59.9-86.4% and baking in the range of 63.2-90.2%. Kruskal-Wallis analysis indicates that the reduction of pesticide residues by baking is significantly different from doughing (p-value < 0.0001). There is also a significant difference between non-fermented and fermented dough (p-value = 0.012). The processing factor for doughing and baking was less than one (PF < 1 = reduction factor) which indicates the reduction of pesticides due to teff processing. The cumulative effect of these processing methods is important to evaluate the risks associated with the ingestion of pesticides, particularly in teff grain.

Determinations of dinotefuran and metabolite levels before and after household coffee processing in coffee beans using solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry

BACKGROUND

Coffee is one of the most popular beverages in the world. However, as daily consumables, coffee beans may contain pesticide residues that are capable of causing adverse health effects. Thus, we investigated residue dynamics in coffee beans using supervised field trials under Good Agricultural Practice conditions and determined the effects of household coffee processing on the coffee-bean pesticide residues dinotefuran and its metabolites 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF) and 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine (DN).

RESULTS

The recovery rate of dinotefuran and its metabolites UF and DN was in the range 73.5%-106.3%, with a relative SD < 10%. The limits of detection and limits of quantification for dinotefuran, UF and DN were all 0.003 and 0.01 mg kg^-1 , respectively. Dissipation experiments were conducted over 2015 and 2016 and showed a mean half-life of 40.8 days. Coffee processing procedures were performed as described for traditional household coffee processing in Ethiopia. Dinotefuran contents were reduced by 44.4%-86.7% with washing of coffee beans and the roasting process reduced these contents by 62.2%-100%. DN residues were not detected in roasted coffee beans before day 21 or in brewed coffee before day 35 and UF residues were not detected in brewed coffee before day 35. Kruskal-Wallis analyses indicated large variations in the stability of pesticide residues between processing methods (P ≤ 0.05). Reductions of pesticide concentrations with washing were also significantly lower than those following roasting (P = 0.0001) and brewing processes (P = 0.002). Moreover, processing factors were less than one for all processing stages, indicating reductions of pesticides contents for all processing stages.

CONCLUSION

The cumulative effects of the three processing methods are of paramount importance with respect to an evaluation of the risks associated with the ingestion of pesticide residues, particularly those in coffee beans. © 2018 Society of Chemical Industry.

Screening for Lactobacillus plantarum Strains That Possess Organophosphorus Pesticide-Degrading Activity and Metabolomic Analysis of Phorate Degradation

This work performed a large scale assessment for organophosphorus pesticides (OPPs) degradation activity of 121 Lactobacillus (L.) plantarum strains. Six L. plantarum strains (P9, IMAU80110, IMAU40100, IMAU10585, IMAU10209, and IMAU80070) were found to possess high capacity of degrading three commonly used OPPs, namely dimethoate, phorate, and omethoate; and they were selected for more detailed characterization. Moreover, the three OPPs were mainly detected in the culture supernatants but not in the cell extracts, further confirming that the OPPs were degraded rather than absorbed by the cells. Among the six selected strains, P9 was most tolerant to gastrointestinal juices and bile. We thus used ultra-high performance liquid chromatography electron spray ionization coupled with time-of-flight mass spectrometry (UPLC/ESI-Q-TOF/MS) to generate the metabolomic profiles of the strain P9 growing in MRS medium with and without containing phorate. By using orthogonal partial least squares discriminant analysis, we identified some potential phorate-derived degradative products. This work has identified novel lactic acid bacteria resources for application in pesticide degradation. Our results also shed light on the phorate degradation mechanism by L. plantarum P9.

Open Access Estimation of deltamethrin residues in cow's and goat's environment and trials to reduce its level in milk

Aim:

The present study was aimed to estimate deltamethrin residues in cow’s and goat’s environment over a certain period of time post-application, to identify the role of both feed and water as a source of pesticides, and to conduct some trials to reduce their levels in milk.

Materials and Methods:

A total of 80 water and feed samples (40 of each) and 120 milk samples (80 cow’s milk and 40 goat’s milk) were collected. Fresh milk samples were collected directly from the udder as well as from feed and water before application and 1^st, 2^nd, 3^rd, 7^th, 15^th, 21^st, and 35^th days after insecticide application.

Results:

Deltamethrin residues were detected after its application in both water and feed at different levels up to the first 3 days and in all cow’s and goat’s milk samples at 35^th day. The highest levels were detected in milk samples at the 2^nd day then at the 7^th day followed at the 15^th day after application as such levels were above the maximum residual limits. By microwaving the polluted cow’s milk samples, deltamethrin residues were not detected without influencing the chemical composition of the milk. However, on freezing of milk, the deltamethrin residues reached 12.6±3.24 μg/L in association with a significant decline in the concentration of fat.

Conclusion:

Microwaving of milk is an effective method to decline deltamethrin concentration in milk.

Industrial prune processing and its effect on pesticide residue concentrations

The aim of this study was to determine the insecticide residue processing factor (PF) from plums to prunes and the effect of the industrial processing of prunes residue concentrations. Our results show an increase of insecticide concentrations during plum dehydration that is explained by fruit water loss; however, the normalized insecticide residue concentration, based on plum dry weights to compensate dehydration, was reduced. The water washing and tenderizing of prunes produced insecticide residue reductions of 22.9 ± 4.5% and 21.9 ± 4.2%, respectively. PF were: 1.157, 1.872, 1.316, 0.192, 2.198, 0.775 and 0.156 for buprofezin, l-cyhalothrin, spirodiclofen, indoxacarb, acetamiprid, imidacloprid and emamectin benzoate, respectively, being directly related to water solubility, aqueous hydrolysis and degradation point and inversely related to molecular mass and melting point. In plums for the dehydrated agroindustry the final product is prunes, therefore, it is crucial to consider the PF to determine the specific preharvest interval for this important agroindustry.

Ozone as degradation agent of pesticide residues in stored rice grains

This work aimed to study the kinetics of bifenthrin and deltamethrin residues degradation in rice grains under exposure to ozone and evaluate the effect of ozonization on rice grains marketing standards. The grains sprayed with pesticides were exposed to ozone at a concentration of 3 mg L-1 and continuous flow of 1.0 L min-1 for defined periods of up to 10 h. Residues of pesticides were extracted from grains using solid liquid extraction method with low-temperature partition analyzed by gas chromatography with electron capture detection (SLE/LTP-GC/ECD). Data from residual concentrations of bifenthrin and deltamethrin, due to the ozone exposure period, were adjusted to kinetic models of zero order, first order and second order. It was observed that ozone was effective in the degradation bifenthrin and deltamethrin residues, removing 91.9% of bifenthrin and 92.7% of deltamethrin. The kinetic model that best fitted deltamethrin and bifenthrin residues degradation data by ozone, was the one of first order. The marketing standards evaluated were the water content and yield. It was observed the ozone did not alter the rice grains water content and yield.

Role of Sample Processing Strategies at the European Union National Reference Laboratories (NRLs) Concerning the Analysis of Pesticide Residues

The guidance document SANTE 11945/2015 recommends that cereal samples be milled to a particle size preferably smaller than 1.0 mm and that extensive heating of the samples should be avoided. The aim of the present study was therefore to investigate the differences in milling procedures, obtained particle size distributions, and the resulting pesticide residue recovery when cereal samples were milled at the European Union National Reference Laboratories (NRLs) with their routine milling procedures. A total of 23 NRLs participated in the study. The oat and rye samples milled by each NRL were sent to the European Union Reference Laboratory on Cereals and Feedingstuff (EURL) for the determination of the particle size distribution and pesticide residue recovery. The results showed that the NRLs used several different brands and types of mills. Large variations in the particle size distributions and pesticide extraction efficiencies were observed even between samples milled by the same type of mill.

The potency of Saccharomyces cerevisiae and Lactobacillus plantarum to dissipate organophosphorus pesticides in wheat during fermentation

The degradation behaviour of pirimiphos methyl with Saccharomyces cerevisiae and chlorpyrifos methyl with Lactobacillus plantarum in wheat during fermentation was studied. Yeast fermentation was especially effective for reduction of pirimiphos methyl applied at 5 mg kg-1 (maximum residue limit-MRL) causing dissipation for max 48.8%. Pesticide reduction rate decreased with an increase of fortification rate. Thus in samples fortified with 25 and 75 mg kg-1 a reduction up to 27.1%, and 23.7% respectively, was observed. Activity of L. plantarum was especially effective for reduction of chlorpyrifos methyl applied at 3 mg kg-1 (MRL) causing dissipation for max 56.7%. This reduction rate decreased with an increase of fortification rate. In samples contaminated with 15 and 45 mg kg-1 dissipation reached up to 38.6% and 34.7% respectively. For both experiments, initial inoculums sizes had no statistically significant effect on pesticides dissipation level, while concerning fermentation temperatures at all fortification levels the highest degradations occurred at 30 °C. Overall, regardless fermentation parameters, the degradation rate constants of pirimiphos methyl fermented with yeast were increased comparing with control samples by 255-573, 56-116 and 119-594% in samples contaminated at MRL, 5MRL and 15MRL of pesticide, while the degradation rate constants of chlorpyrifos methyl fermented with lactobacilli were increased by 74-769, 59-237 and 46-469% respectively. These results evidenced that yeast and lactobacilli played an important role in promoting pirimiphos methyl i.e. chlorpyrifos methyl dissipation in wheat.

Biodegradation of two organophosphorus pesticides in whole corn silage as affected by the cultured Lactobacillus plantarum

Biodegradation of the pesticides is considered as one of the safest and cheapest ways. The aim of the present study was to reveal if the inoculated Lactic acid bacteria widely used in silage could provide beneficial safety to guarantee dairy feedstuffs and fresh milk. Organophosphorus pesticides (OPPs) degradation in whole corn silage was investigated. Two OPPs, chlorpyrifos and phorate, were added to the whole corn, which was inoculated with L. plantarum 1.0315, L. plantarum 1.0624, L. plantarum 1.0622 and their combination at room temperature for 10 weeks. OPPs residues in the whole corn silage at different weeks were analyzed by gas chromatography after OPPs extraction and purification. The degradation rate constants were calculated according to the OPPs residues results at different fermentation stage. The data showed that the inoculated microorganisms and strain combination exhibited obvious acceleration on OPPs degradation as the wild microorganisms did, and resulted in decreased levels of OPPs from 24.9 to 33.4 %. Strains combination brought about greater OPPs degradation than single strain or the wild microorganisms. Compared to phorate, clorpyrifos had lower degradation rate constants (0.0274–0.0381 vs. 0.0295–0.0355 week⁻¹) and was more stable. The present result indicates safety benefit of lactic acid bacteria on corn silage besides lactic acid fermentation.

Effect of Household Coffee Processing on Pesticide Residues as a Means of Ensuring Consumers' Safety

Coffee is a highly consumed and popular beverage all over the world; however, coffee beans used for daily consumption may contain pesticide residues that may cause adverse health effects to consumers. In this monitoring study, the effect of household coffee processing on pesticide residues in coffee beans was investigated. Twelve pesticides, including metabolites and isomers (endosulfan α, endosulfan β, cypermethrin, permethrin, deltamethrin, chlorpyrifos ethyl, heptachlor epoxide, hexachlorobenzene, p'p-DDE, p'p-DDD, o'p-DDT, and p'p-DDT) were spiked in coffee beans collected from a local market in southwestern Ethiopia. The subsequent household coffee processing conditions (washing, roasting, and brewing) were established as closely as possible to the traditional household coffee processing in Ethiopia. Washing of coffee beans showed 14.63-57.69 percent reduction, while the roasting process reduced up to 99.8 percent. Chlorpyrifos ethyl, permethrin, cypermethrin, endosulfan α and β in roasting and all of the 12 pesticides in the coffee brewing processes were not detected. Kruskal-Wallis analysis indicated that the reduction of pesticide residues by washing is significantly different from roasting and brewing (P < 0.0001). However, there was no significant difference between coffee roasting and brewing (P > 0.05). The processing factor (PF) was less than one (PF < 1), which indicates reduction of pesticides under study during processing of the coffee beans. The cumulative effect of the three processing methods has a paramount importance in evaluating the risks associated with ingestion of pesticide residues, particularly in coffee beans.

TDS exposure project: relevance of the total diet study approach for different groups of substances

A method to validate the relevance of the Total Diet Study (TDS) approach for different types of substances is described. As a first step, a list of >2800 chemicals classified into eight main groups of relevance for food safety (natural components, environmental contaminants, substances intentionally added to foods, residues, naturally occurring contaminants, process contaminants, contaminants from packaging and food contact materials, other substances) has been established. The appropriateness of the TDS approach for the different substance groups has then been considered with regard to the three essential principles of a TDS: representativeness of the whole diet, pooling of foods and food analyzed as consumed. Four criteria were considered for that purpose (i) the substance has to be present in a significant part of the diet or predominantly present in specific food groups, (ii) a robust analytical method has to be available to determine it in potential contributors to the dietary exposure of the population, and (iii) the dilution impact of pooling and (iv) the impact of everyday food preparation methods on the concentration of the substance are assessed. For most of the substances the TDS approach appeared to be relevant and any precautions to be taken are outlined.

Effect of handling and processing on pesticide residues in food- a review

Pesticides are one of the major inputs used for increasing agricultural productivity of crops. The pesticide residues, left to variable extent in the food materials after harvesting, are beyond the control of consumer and have deleterious effect on human health. The presence of pesticide residues is a major bottleneck in the international trade of food commodities. The localization of pesticides in foods varies with the nature of pesticide molecule, type and portion of food material and environmental factors. The food crops treated with pesticides invariably contain unpredictable amount of these chemicals, therefore, it becomes imperative to find out some alternatives for decontamination of foods. The washing with water or soaking in solutions of salt and some chemicals e.g. chlorine, chlorine dioxide, hydrogen peroxide, ozone, acetic acid, hydroxy peracetic acid, iprodione and detergents are reported to be highly effective in reducing the level of pesticides. Preparatory steps like peeling, trimming etc. remove the residues from outer portions. Various thermal processing treatments like pasteurization, blanching, boiling, cooking, steaming, canning, scrambling etc. have been found valuable in degradation of various pesticides depending upon the type of pesticide and length of treatment. Preservation techniques like drying or dehydration and concentration increase the pesticide content many folds due to concentration effect. Many other techniques like refining, fermentation and curing have been reported to affect the pesticide level in foods to varied extent. Milling, baking, wine making, malting and brewing resulted in lowering of pesticide residue level in the end products. Post harvest treatments and cold storage have also been found effective. Many of the decontamination techniques bring down the concentration of pesticides below MRL. However, the diminution effect depends upon the initial concentration at the time of harvest, substrate/food and type of pesticide. There is diversified information available in literature on the effect of preparation, processing and subsequent handling and storage of foods on pesticide residues which has been compiled in this article.

Stability of the pyrethroid pesticide bifenthrin in milled wheat during thermal processing, yeast and lactic acid fermentation, and storage

BACKGROUND

Pesticide residues have become an unavoidable part of food commodities. In the context of increased interest for food processing techniques as a tool for reducing pesticide residues, it is interesting to study the potential loss of pesticides during lactic acid and yeast fermentation. In the present paper the effect of fermentation by Lactobacillus plantarum and Saccharomyces cerevisiae and storage on 23 °C on bifenthrin in wheat was investigated. In addition, the effect of sterilisation (applied in order to avoid contamination with wild microorganism strains, i.e. to determine the individual effects of used strains) on bifenthrin degradation was tested as well.

RESULTS

No significant loss of bifenthrin was observed during storage, or after the sterilisation. During the lactic acid fermentation, reduction within wheat fortified with 0.5 mg kg(-1) was 42%, while quite lower within samples fortified with 2.5 mg kg(-1) , maximum 18%. In contrast, bifenthrin concentration was not reduced during yeast fermentation, as the reduction in fortified samples was in the range of spontaneous chemical degradation during incubation period.

CONCLUSION

Possible bifenthrin contamination in wheat, in amounts over the maximum residue limits, could not be reduced by sterilisation or by yeast fermentation, but lactic acid fermentation could be an effective tool for minimising residual contamination.

Dissipation of pirimiphos-methyl during wheat fermentation by Lactobacillus plantarum

In this study, the dissipation of pirimiphos-methyl during wheat fermentation by Lactobacillus plantarum was investigated. Sample preparation for GC/MS detection of pirimiphos-methyl residues from fermented wheat substrate was carried out by two steps: extraction with 25 mL of methanol : acetone = 1 : 1 solvent mix for 30 min, followed by clean-up procedure through a glass column with florisil coupled with elution by 25 mL of ethyl acetate : acetone = 4 : 1. To obtain the highest pesticide degradation level, the fermentation conditions were optimized according to response surface methodology. Our results showed that L. plantarum was able to reduce the level of pirimiphos-methyl in wheat. Although pirimiphos-methyl was partially labile during sterilization prior inoculation (~37-50%), and there was also spontaneous chemical degradation of pesticide (~6-11%), overall L. plantarum enhanced degradation from 15 to 34%, that is, to nearly 81%. Additionally, the effect of pirimiphos-methyl on the lactobacilli growth, and efficiency of fermentation, was studied where pirimiphos-methyl inhibit the growth of bacteria in concentrations higher than 5 mg kg(-1), while the presence of pirimiphos-methyl did not overall affect the lactic acid fermentation.

Plant uptake of pesticides and human health: dynamic modeling of residues in wheat and ingestion intake

Human intake of pesticide residues from consumption of processed food plays an important role for evaluating current agricultural practice. We take advantage of latest developments in crop-specific plant uptake modeling and propose an innovative dynamic model to estimate pesticide residues in the wheat-environment system, dynamiCROP. We used this model to analyze uptake and translocation of pesticides in wheat after foliar spray application and subsequent intake fractions by humans. Based on the evolution of residues in edible parts of harvested wheat we predict that between 22 mg and 2.1 g per kg applied pesticide are taken in by humans via consumption of processed wheat products. Model results were compared with experimentally derived concentrations in wheat ears and with estimated intake via inhalation and ingestion caused by indirect emissions, i.e. the amount lost to the environment during pesticide application. Modeled and measured concentrations in wheat fitted very well and deviate from less than a factor 1.5 for chlorothalonil to a maximum factor 3 for tebuconazole. Main aspects influencing pesticide fate behavior are degradation half-life in plant and time between pesticide application and crop harvest, leading to variations in harvest fraction of at least three orders of magnitude. Food processing may further reduce residues by approximately 63%. Intake fractions from residues in sprayed wheat were up to four orders of magnitude higher than intake fractions estimated from indirect emissions, thereby demonstrating the importance of exposure from consumption of food crops after direct pesticide treatment.