Effect of paste processing on residue levels of imidacloprid, pyraclostrobin, azoxystrobin and fipronil in winter jujube

Dissipation, Residue and Human Dietary Risk Assessment of Pyraclostrobin and Cyazofamid in Grapes Using an HPLC-UV Detector

Pyraclostrobin is a new broad-spectrum methoxyacrylic acid fungicide. Cyazofamid is a new selective foliar spray acaricide. Here, we studied the degradation rate and final residues of pyraclostrobin and cyazofamid in grape and evaluated their dietary risk to consumers. The average recoveries of pyraclostrobin ether ester, cyazofamid and cyazofamid metabolite (CCIM) in grapes were 84-94%, 92-98% and 99-104%, respectively. The relative standard deviations (RSDs) were 6.0-20.3%, 2.4-10.5% and 1.3-4.0%, respectively, and the LOQs were all 0.05 mg/kg. The digestion dynamics of the experimental sites were in accordance with the first-order kinetic equation. The degradation half-lives of pyraclostrobin ether ester and cyazofamid were 17.8 d-28.9 d and 4.3 d-7.8 d, respectively. The final residues of pyraclostrobin ether ester, cyazofamid and CCIM in grapes were <0.05-1.88 mg/kg, <0.05-0.31 mg/kg and <0.05-0.47 mg/kg, respectively. Using probability models, the total chronic risk values for pyraclostrobin and cyazofamid were calculated to be 0.112-189.617% and 0.021-1.714%, respectively. The results of the contribution analysis indicate that pyraclostrobin poses a much greater risk to Chinese consumers than cyazofamid, especially to children and adolescents, who have a significantly greater risk than adults. This suggests that more consideration should be given to the cumulative risk of compounds for vulnerable groups in the future.

Simultaneous determination of residues of multiple pesticides and their metabolites in citrus and orange juice from markets in China: residue levels and dietary risk assessment

Consumers are becoming more concerned about pesticide residues in food. Since citrus represent a significant portion of the diet, it is appropriate to monitor the pesticide residues in citrus. In this paper, we modified a QuEChERS method combined with HPLC-MS/MS to investigate residue levels of 15 pesticides and 3 metabolites in citrus (whole fruit and pulp) and orange juice from the markets in China. And the dietary exposure risks were evaluated by using the hazard quotient (HQ) and hazard index (HI) methods based on deterministic and probabilistic models. The recoveries of the modified method ranged from 70 to 112% at three spike levels of 0.005-0.5 mg/kg with relative standard deviations of 1.0-18.1%. Pesticide residues were detected in 85.84% of the whole citrus and 40.00% of pulp, with concentrations ranging from 0.005 to 0.47 mg/kg, which did not exceed their maximum residue limits (MRLs) in China. The HQ (0.01-11.41%) and HI (0.07-16.2%) were both less than 100%, demonstrating that chronic, acute, and cumulative dietary risks were acceptable. Notably, the risk for children (1-6 years old, 1.96-16.2%) was higher than that for the general population (0.76-6.25%). The results of our study can provide a valuable reference for regular monitoring to protect public health and ensure pesticide management.

Effect of decontamination and processing on insecticide residues in grape (Muscat Hamburg)

Field and laboratory experiments were conducted to study the effect of simple decontamination methods and processing on imidacloprid, dimethoate, and emamectin benzoate residues in grapes and their processed products by liquid chromatography-mass spectrometry. Among the decontamination methods evaluated, washing with NaCl (2%) solution was effective for reducing imidacloprid (77.55%), dimethoate (83.27%), and emamectin benzoate (77.28%) residues in mature grapes. No metabolites (omethoate and 6-chloronicotinic acid) were detected in both decontamination and processing studies. The grapes were processed into various products, including fresh juice, squash, and raisin, following the standard effective steps for each product. Washing with NaCl (2%) solution for decontamination was included as an additional step in the standard protocol and resulted in substantial removal of surface residues of the selected insecticides. The processing factor calculated was less than one for all the products.

Enantioselective fate of famoxadone during processing of apple cider and grape wine

Famoxadone enantiomers were separated on Lux Amylose-1 chiral column and determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The half-lives of R-(-)-famoxadone and S-(+)-famoxadone were 69.3 and 86.6 h in apple cider, 231.0 and 346.5 h in apple pomace, 69.3 and 77.0 h in grape wine, and 231.0 and 346.5 h in grape pomace, respectively. The enantiomeric fraction (EF) values decreased gradually from 0.498, 0.499, and 0.500 (0 h) to 0.404, 0.374, and 0.427 (144 h) and then increased gradually to 0.474, 0.427, and 0.422 (312 h) in apple cider, grape wine, and grape pomace. The EF value in apple pomace decreased gradually from 0.499 (0 h) to 0.450 (168 h) and then increased gradually to 0.482 (312 h). The processing factors (PFs) for famoxadone ranged from 0.014 to 0.024 in the overall process. The residue of famoxadone reduced 94.7-97.4% after the fermentation process.

Mechanism insights into the transformation of carbosulfan during apple drying processes

The transformation of carbosulfan (CSN) in apples was investigated during oven-drying, microwave drying, and sun-drying. CSN transformed primarily into carbofuran (COA) during these drying processes. The conversion kinetics of CSN and COA was fitted by curve regression and mainly conformed to quadratic models (R² = 0.70-0.97). Oven-drying promoted the transformation of CSN into COA. Microwave drying resulted in the highest scavenging capacity against CSN and COA (41%-100%). Moreover, a transformation mechanism was proposed on the basis of density functional theory (DFT) calculation. The COA originated from a series of chemical reactions involving hydroxyl substitution, cleavage, and oxidation; this result was further confirmed on the basis of molecular electrostatic potential (MEP) and molecular orbital theory. Furthermore, the toxicity and stability of CSN and COA were evaluated with the T.E.S.T. program. COA was less toxic than CSN to aquatic organisms but more toxic than CSN to rats. Therefore, COA production should be avoided during drying. Microwave drying was found to be the optimum choice for drying apples.

Effects of processing and storage on pesticide residues in foods

Pesticides are chemicals frequently used in agriculture to obtain maximum yield and improve product quality. Thousands of active ingredients and formulations of different pesticides are commercially available. Besides their advantages, a major disadvantage of pesticides is their residues, even though strict maximum residue limits have been set for each pesticide and permitted agricultural commodity. Permanence of pesticide residues on agricultural products depends on several factors such as the properties of pesticide, formulation, and applied concentration. Light, temperature, plant morphology, and plant growth factors are also effective in determining permanence. Degradation effects of the processing treatments rely on the dissolution of pesticides in the surrounding atmosphere, hydrolysis, microbial degradation, oxidation, penetration, and photo-degradation. Various steps applied during food processing, such as washing with water or other aqueous solutions, peeling, chopping, pickling, heat treatments, and processes such as drying, canning, fruit juice and concentrate production, malt, beer and wine production, oil production, and storage have certain effects on the presence of pesticide residues as well. Only washing with water can remove pesticide residue up to 100%, depending on the location of residue, residence time on food, water solubility of residue, washing temperature, and agents used to increase effectiveness. Besides washing, skin removal or peeling is one of the most effective treatments for residue removal, especially on non-systemic pesticides. During cooking, residues might be evaporated or hydrolyzed. Effects of storage temperature on reduction are related to volatilization, penetration, metabolism of pesticide, moisture content, and microbial growth, if any. In refrigerated or frozen storage, residues are stable or degrade slowly. Drying may increase the residue content because of the concentration, but in sun-drying reduction may occur because of photo-degradation. Clarification and filtration may eliminate residues retained in suspended particles. The degradation product, however, may be more toxic than the initial compound in some cases.

Residue behaviours, dissipation kinetics and dietary risk assessment of pyaclostrobin, cyazofamid and its metabolite in grape

BACKGROUND

Grape is an important fruit consumed either fresh or processed, therefore, fungicide misuse of grape has become an issue of global food safety and human health. Pyraclostrobin, and cyazofamid have been applied to grape frequently.

RESULTS

Here a simple QuEChERS (quick, easy, cheap, effective, rugged, and safe) liquid chromatography mass spectrometry technique has been developed and validated for the determination of pyraclostrobin, cyazofamid and its metabolite CCIM in open field grape samples. The recoveries of these three in the range of 0.01 to 5 mg kg^-1 (n = 5) ranged from 73.1% to 97.9%. The relative standard deviations (RSDs) were below 12% for all cases. The limits of quantitation of each analyte was 0.005 mg kg^-1 , which was lower than maximum residue limits of not only pyraclostrobin but also cyazofamid. Not only dissipation kinetics but also residue determination was obtained in grape for those three pesticides. Furthermore, their half-lives in grapes were 10.7-30.1 days, recommending the pre-harvest intervals for these three of 14 days. The calculated hazard quotient and acute hazard index lower than 100% illustrated the safety of intake of grape for the Chinese population for not only long-term but also short-term dietary risk assessment.

CONSLUSIONS

The less than 30 day half-life illustrated that pyraclostrobin and cyazofamid could degrade relatively easily in the environment. The long-term and short-term dietary risk assessment also illustrated the intake safety of these three. Thus, a 14 day pre-harvest interval was safe and recommended. The results of this study contributed to environmental protection, food safety and human health. © 2019 Society of Chemical Industry.

Residue Distribution, Dissipation Behavior, and Removal of Four Fungicide Residues on Harvested Apple after Waxing Treatment

The residue distribution and dissipation of pyrimethanil, fludioxonil, cyprodinil, and kresoxim-methyl, which were introduced during postharvest waxing treatments of apples, were investigated. In addition, different residue removal methods were tested for the four fungicides in apples, and the removal efficiencies were compared. A multiresidue analytical method was developed based on quick, easy, cheap, effective, rugged, and safe method (QuEChERS) for the determination of the fungicide residues in apples. The dissipation study demonstrated that there was no significant change of fungicide residue magnitude during a 40-day storage process under ambient temperature. The fungicide residues in apples by wax treatment were shown to be very much stable. The results of residue distribution study demonstrated that waxing treatment may help to reduce the risk of pesticide when only the pulp was consumed. In the residue removal study, results suggested that higher temperature and the addition of acetic acid can improve the residue removal efficiency.

How effective are common household preparations on removing pesticide residues from fruit and vegetables? A review

Nowadays, the use of pesticides is inevitable for pest control in crops, especially for fruit and vegetables. After the harvest from raw agricultural commodities, the amount of pesticide residues in food is mainly influenced by the storage, handling and processing that follow. If good agricultural and good manufacturing practices are enforced effectively, the amount of pesticide residues would be brought below the corresponding maximum residue level. Thus, the consumption of raw and/or prepared fruit and vegetables would be safe. Nonetheless, reports regarding pesticide residues in fruit or vegetables on mass media have been worrying consumers, who are concerned about the adverse effects of pesticide residues. As a result, consumers perform household processing before consumption to reduce any related risks. However, can these preparations effectively remove pesticide residues? Reviewing the extensive literature, it showed that, in most cases, washing and soaking can only lead to a certain degree of reduction in residue level, while other processing such as peeling, soaking in chemical baths and blanching can reduce pesticide residues more effectively. In general, the behaviour of residues during processing can be rationalised in terms of the physico-chemical properties of the pesticide and the nature of the process. In contrast, the reported studies are diversified and some areas still lack sufficient studies to draw any remarks. Recommendations are provided with respect to the available information that aims to formulate an environmental friendly, cost-effective and efficient household processing of fruit and vegetables to reduce pesticide residues. © 2017 Society of Chemical Industry.

Dissipation and Migration of Pyrethroids in Auricularia polytricha Mont. from Cultivation to Postharvest Processing and Dietary Risk

In order to ensure raw consumption safety the dissipation behavior, migration, postharvest processing, and dietary risk assessment of five pyrethroids in mushroom (Auricularia polytricha Mont.) cultivated under Chinese greenhouse-field conditions. Half-lives (t1/2) of pyrethroids in fruiting body and substrate samples were 3.10-5.26 and 17.46-40.06 d, respectively. Fenpropathrin dissipated rapidly in fruiting bodies (t1/2 3.10 d); bifenthrin had the longest t1/2. At harvest, pyrethroid residues in A. polytricha (except fenpropathrin) were above the respective maximum residue limits (MRLs). Some migration of lambda-cyhalothrin was observed in the substrate-fruit body system. In postharvest-processing, sun-drying and soaking reduced pyrethroid residues by 25-83%. We therefore recommend that consumers soak these mushrooms in 0.5% NaHCO₃ at 50 °C for 90 min. Pyrethroids exhibit a particularly low PF value of 0.08-0.13%, resulting in a negligible exposure risk upon mushroom consumption. This study provides guidance for the safe application of pyrethroids to edible fungi, and for the establishment of MRLs in mushrooms to reduce pesticide exposure in humans.

Residue analysis and risk assessment of tebuconazole in jujube (Ziziphus jujuba Mill)

In this study, a sensitive and reliable analytical method, based on a modified Quick, Easy, Cheap, Effective, Rugged and Safe procedure, was established for determination of tebuconazole in jujube. After extraction with acetonitrile, the samples were cleaned up by dispersive solid-phase extraction with primary secondary amine, and determined by high-performance liquid chromatography tandem mass spectrometry. At fortification levels of 0.01, 0.1 and 2.0 mg kg^-1 , the average recoveries of tebuconazole in jujube were in the range 97.6-101.9%, with relative standard deviations of 1.5-3.5%. The dissipation and residual levels of tebuconazole in jujube under field conditions were investigated. Tebuconazole dissipated relatively slowly in jujube, with a half-life of 33.0 days. The terminal residue experiments of tebuconazole in jujube were conducted in four locations in China and the risk was evaluated using risk quotients (RQ). RQ values were found to be significantly lower than RQ = 1, indicating that the risk to human health of using the recommended doses of tebuconazole in jujube was not significant. This study could provide guidance for the safe and reasonable use of tebuconazole in jujube and serve as a reference for the establishment of limit of maximum residue in China.

Behaviour of spirotetramat residues and its four metabolites in citrus marmalade during home processing

The effect of home processing on the residues of spirotetramat and its four metabolites (B-enol, B-glu, B-mono and B-keto) in citrus marmalade is comprehensively investigated in this paper by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A five-fold recommended dose of spirotetramat was applied to citrus fruit under field conditions and the processing included five steps: washing, peeling, pre-treatment for peel, mixing and boiling. The results showed that spirotetramat was the predominant component detected in unprocessed citrus, accounting for 64%. All the detected residues were primarily deposited on citrus peel, except for B-enol which was also present in the citrus pulp. Washing reduced spirotetramat, B-enol, B-glu and B-keto by 83%, 56%, 41% and 16%, respectively, and pre-treatment of the peel removed between 42% and 68% of the residues. Four compounds were all below the limit of detection after the mixing step. In the final product, only B-keto was detected at the concentration of 0.010 mg kg(-1). After the whole process, the processing factors for spirotetramat, B-enol, B-glu and B-keto were < 0.041, < 0.125, < 0.294 and 0.313, respectively, which indicated that home processing can significantly reduce residues of spirotetramat and its metabolites in citrus marmalade.