Residue contents of DDVP (Dichlorvos) and diazinon applied on cucumbers grown in greenhouses and their reduction by duration of a pre-harvest interval and post-harvest culinary applications

Controlled applications of DDVP (Dichlorvos) and diazinon were carried out on cucumbers grown in two different greenhouses at different times. The first group of samples was collected 4 h after the application and the second group was collected 4 days later, which was the mean cropping period applied in this region following maturation of the cucumber plant. Additionally, control samples were collected before application. The effects of washing, peeling and predetermined storage periods, at 4 °C for 3 and 6 days, on the reduction of residue levels in the plant tissues were investigated in the two groups. A gas chromatographic method, using acetone, dichloromethane and petroleum ether, as extraction solvents was used to analyse residual DDVP and Diazinon in cucumbers, with obtained recoveries greater than 81%. DDVP and Diazinon were determined by gas chromatography–electron capture detection (GC–ECD) equipped with a 5% phenylmethylpolysiloxane-coated fused-silica capillary column.Results showed that residue levels in samples, which were collected after 4 days following the pesticide application, were significantly lower than the samples collected after 4 h subsequent to the pesticide application. Culinary applications, such as washing and peeling and refrigeration storage, were also effective in reducing the residue levels.     

Residue content of carbaryl applied on greenhouse cucumbers and its reduction by duration of a pre‐harvest interval and post‐harvest household processing

BACKGROUND: Carbaryl is widely used to control various insect pests on greenhouse cucumbers in Iran. Therefore the control of residual levels of this insecticide is highly necessary. The effects of the household processing such as washing, peeling and refrigeration storage, at 4 °C for 2 days on the reduction of residue levels in the plant tissues were investigated in the different groups. Samples were collected at 1 h to 14 days after application and analysed to determine the content and dissipation rate of carbaryl. Analysis was carried out by the QuEChERS method using HPLC‐UV. RESULTS: Carbaryl residue in samples, which were collected post‐application in different times showed a gradual and significant (P < 0.05) decrease. The half‐life (t_1/2) of carbaryl applied on cucumbers was 3.2 days. Carbaryl residues were detected in concentration ranges of 0.22–4.91 mg kg^?1. Also, the results indicated that the consumable safety time of carbaryl was found to be more than 14 days on cucumber. CONCLUSION: Household processing, such as washing and peeling and refrigeration storage, was effective in reducing the residue levels. Also, peeling was the most effective way to reduce the carbaryl residues of the cucumber samples. Washing and refrigerated storage also decreased carbaryl residues. Copyright © 2010 Society of Chemical Industry     

The decrease in pesticides in fruit and vegetables during commercial processing

Samples of tomatoes, peppers, asparagus, spinach and peaches were exposed to three insecticides (acephate, chlorpyrifos and cypermethrin), three ethylenebisdithiocarbamate fungicides (mancozeb, maneb, propineb) and the tetramethyldithiocarbamate fungicide thiram to study the effect of commercial processing on the residues. In most cases, canning operations led to a gradual decrease in residue levels in the finished products, particularly through washing, blanching, peeling and cooking processes. The results indicated that washing plus blanching led to more than 50% loss in pesticide residues, except for in peaches. Ethylenebisdithiocarbamates (EBDCs) were completely removed from tomatoes and spinach by washing followed by hot water blanching. The total amount of pesticide removed by all of the combined canning operations ranged from 90 to 100% in most products. Pepper retained 61% of chlorpyrifos but these residues disappeared during 3‐month storage of finished cans. Acephate showed a surprising tenacity in peaches, as 11% of the original residues were still present in 2‐year stored cans.     

Residue levels of captan and trichlorfon in field-treated kaki fruits, individual versus composite samples, and after household processing.

The dissipation of residue levels of captan and trichlorfon in field-treated kaki crops was studied according to good laboratory practices to propose maximum residue limits (MRLs). Residue levels of captan and trichlorfon were analysed by GC/MS and LC-MS/MS, respectively. Residue levels of captan and trichlorfon permitted one to propose MRLs in kaki of 3 and 5 mg kg(-1), respectively. The behaviour of these residues was also studied after peeling and cooking, and in individual fruits versus composite samples. Residue levels of these compounds for individual fruits suggested that a variability factor up to three could be set for the acute risk assessment. Levels of captan decreased by more than 90% after peeling and completely after cooking. Trichlorfon penetrates into the flesh in a proportion of 70% of the residue at the pre-harvest interval. Cooking resulted in a decrease of 27% of residue levels of trichlorfon.     

Inactivation of Salmonella during drying and storage of Roma tomatoes exposed to predrying treatments including peeling, blanching, and dipping in organic acid solutions

The objective of this study was to evaluate the influence of predrying treatments, i.e., peeling, blanching prior to inoculation, and dipping in organic acid solutions, on inactivation of Salmonella during drying (60 degrees C for 14 h) and aerobic storage (25 degrees C for 28 days) of inoculated (five-strain composite, 7.1 to 7.4 log CFU/g) Roma tomato halves. Four predrying treatments groups were established. One group received no treatment (C). In the other three groups, unpeeled-unblanched, unpeeled-blanched (steam blanched at 88 degrees C for 3 min), peeled-unblanched, and peeled-blanched tomato halves were immersed for 10 min in water (W), ascorbic acid solution (AA; 3.40%, pH 2.48), or citric acid solution (CA; 0.21%, pH 2.51). Appropriate dilutions of homogenized tomato samples were spread plated on tryptic soy agar with 0.1% pyruvate and XLT4 agar for bacterial enumeration during drying and storage. Ten minutes of immersion in W, AA, or CA reduced bacterial populations by 0.7 to 1.6 log CFU/g. After 14 h of dehydration, total log reductions in the populations of bacteria were 3.2 to 4.5 (C), 3.7 to 4.9 (W), > 5.6 to > 6.1 (AA), and 4.5 to 5.5 (CA) log CFU/g, depending on type of agar used and condition of tomato samples. During drying and storage, the order of pathogen inactivation for predrying dipping treatments was AA > CA > W > C, with AA and CA rendering bacterial populations below detectable levels ( < 1.3 log CFU/g) prior to storage and between 7 and 14 days of storage, respectively. The results also indicated that peeling and blanching of tomatoes prior to inoculation may not necessarily affect destruction of Salmonella during the drying process. Use of predrying acid dipping treatments of tomatoes, especially in AA, may improve destruction of Salmonella during the dehydration process.     

Dissipation rates of iprodione and thiacloprid during tomato production in greenhouse

The behaviour of the insecticide thiacloprid and the fungicide iprodione was investigated in greenhouse tomato fruits, when both pesticides were applied in two different rates (normal dose-ND, and double dose-DD). Thiacloprid residues were below the already established EU MRLs (0.5 mg/kg) 2 and 7 days after ND and DD application, respectively. Iprodione residues were always below EU MRLs (5 mg/kg) in both application rates. The impact of storage on pesticide residues in tomatoes was also assessed. Significantly higher iprodione residue levels were observed during post harvest storage compared with those determined in fresh harvested tomatoes. Mean residue levels determined in fresh harvested tomatoes 12 days after iprodione application were 0.69 mg/kg whereas, in post harvest tomatoes stored for the same period was 0.86 mg/kg. On the contrary, no differences were noticed in thiacloprid residues between post harvest stored and fresh harvested tomatoes. Model equations that best describe the dissipation curves obtained from the experimental data of iprodione and thiacloprid in tomatoes showing different behaviour of the two pesticides. Half-life period of iprodione in ND treatment, calculated by the best fitted experimental data, (2nd order model) was 6.8 days, whilst for thiacloprid the best fitted to experimental data, model equation (R.F. 1st order model) gave a half-life of 1.9 days.     

酸性电生功能水联合超声波去除马铃薯净菜中4种农药残留效果分析

为研究电生功能水联合超声波清洗对马铃薯净菜中农药残留的去除效果,对采用不同切割方式的马铃薯净菜进行腐霉利、甲拌磷、百菌清和毒死蜱混合模拟污染,通过QuEChERS前处理方法结合气相色谱-质谱联用法(GC-MS)进行检测,得到酸性电生功能水(AcEW)-超声波清洗处理对马铃薯净菜中4种农药残留的去除率,探讨不同清洗液、样...     

Household vegetable processing practices influencing occurrence of pesticide residues in ready-to-eat vegetables

Influence of vegetable processing on pesticide residues in ready-to-eat vegetables studied at the experimental level does not necessarily reflect actual situation at household level. This study assessed influence of household vegetable processing practices on pesticide residues in ready-to-eat vegetables at household level in Arusha, Tanzania. Data on vegetable handling practices were collected through observations and physical interviews in 70 households. Samples of raw and ready-to-eat vegetables were collected from the households for pesticide residues analysis. Detectable pesticide levels were found in 46% of raw and 14% of ready-to-eat vegetable samples. Pesticide residues detected were in the groups of organophosphates (22.8%), pyrethroids (14.3%), organochlorines (7.14%), benzoic acids (7.14%), and carbamates (5.71%). Unauthorized pesticides (dichlorvos, tetramethrin, and bendiocarb) and environmentally persistent pesticide (dieldrin) were found at levels above their respective maximum residue levels. Washing of vegetables twice or more (p = .01) or peeling (p = .008) was significantly associated with reduction of pesticide residues. There was a significant association between occurrence of pesticide residues in ready-to-eat vegetables and washing of minor ingredients with the water used to wash major ingredients (p = .001). Household practices of washing of vegetables with portable water followed with peeling can reduce pesticide residue levels significantly.     

Behavior of pesticides in tomatoes during commercial and home preparation

Monitoring of pesticide residues in Egyptian tomatoes and its products was studied. The average contents of HCB, lindane, dieldrin, heptachlor epoxide and DDT derivatives were detected at levels 0.009, 0.003, 0.006, 0.008 and 0.083 mg/kg, respectively. On the other hand, the levels of dimethoate, profenofos and pirimiphos-methyl were 0.461, 0.206 and 0.114 mg/kg, respectively. In ketchup and paste samples, most organochlorine and organophosphorus pesticide residues were not detectable. The distribution patterns of pesticide residues within the cuticular and subcuticular tissues in tomatoes were also studied. The skin samples were found to contain the highest levels of HCB, lindane, dieldrin and DDT derivatives. The investigation also indicated that washing with water and/or detergent solution were necessary to decrease the intake of pesticide residues. Freezing, as well as juicing and peeling, were necessary to remove pesticide residues in the skin. Cooking of tomatoes (including processing tomato to paste) helped to eliminate most pesticide residues from contaminated tomatoes. ©     

Food processing a tool to pesticide residue dissipation – A review

Food safety is an area of growing worldwide concern on account of its direct bearing on human health. The presence of harmful pesticide residues in food has caused a great concern among the consumers. Hence, world over to tackle food safety issues, organic farming is being propagated. However, due to several reasons, diffusion and acceptance of this approach in developing countries has been very slow. Therefore, it is important in the transient phase that some pragmatic solution should be developed to tackle this situation of food safety. Food processing treatments such as washing, peeling, canning or cooking lead to a significant reduction of pesticide residues. In this background this paper reviews the common food processing operations along with the degree of residue removal in each process. The processes reviewed include: baking, bread making, dairy product manufacture, drying, thermal processing, fermentation, freezing, infusion, juicing, malting, milling, parboiling, peeling, peeling and cooking, storage, storage and milling, washing, washing and cooking, washing and drying, washing and peeling, washing peeling and juicing and wine making. Extensive literature review demonstrates that in most cases processing leads to large reductions in residue levels in the prepared food, particularly through washing, peeling and cooking operations.     

Field incurred chlorpyrifos and 3,5,6-trichloro-2-pyridinol residues in fresh and processed vegetables

The effect of washing, peeling and cooking on residue levels of chlorpyrifos and 3,5,6-trichloro-2-pyridinol (TCP) in winter (spinach, cauliflower, potato) and summer vegetables (eggplant, tomato, okra) was determined. Analysis was carried out by capillary gas chromatography (DB-5MS capillary column) with mass selective detection. The samples were collected from trials conducted under controlled conditions as well as from the farmer’s field. In supervised field trials, the highest chlorpyrifos residue was found at raw stage in spinach (1.87 mg kg⁻¹) followed by okra (1.41 mg kg⁻¹) and eggplant (1.25 mg kg⁻¹). The lowest residue of chlorpyrifos was recorded in cauliflower (0.036 mg kg⁻¹). The chlorpyrifos residue reduced from 15 to 33% after washing, 65–85% post-peeling and cooking further lowered it from 12% to 48% in all the tested vegetables; while an increase in TCP concentration was observed during heat treatment. Out of 267 vegetable samples collected from the farmer’s field, 225 samples contained detectable residues representing 84% rate of contamination. About 6% of samples contained chlorpyrifos residues above maximum residue limits (MRLs). However, vegetable processing reduced the chlorpyrifos residue below the MRL.     

Distribution behaviour of acaricide cyflumetofen in tomato during home canning

The distribution behaviour of cyflumetofen in tomatoes during home canning was studied. The targeted compound cyflumetofen was determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) after each process step, which included washing, peeling, homogenisation, simmering and sterilisation. Results indicated that more cyflumetofen was removed by washing with detergent solution compared with tap water, 2% NaCl solution and 2% CH₃COOH solution. Peeling resulted in 90.2% loss of cyflumetofen and was the most effective step at removing pesticide residues from tomatoes. The processing factors (PFs) of tomato samples after each step were generally less than 1; in particular, the PF of the peeling process for cyflumetofen was 0.28.     

Influence of unit operations on the levels of polyacetylenes in minimally processed carrots and parsnips: An industrial trial

Carrots and parsnips are often consumed as minimally processed ready-to-eat convenient foods and contain in minor quantities, bioactive aliphatic C17-polyacetylenes (falcarinol, falcarindiol, falcarindiol-3-acetate). Their retention during minimal processing in an industrial trial was evaluated. Carrot and parsnips were prepared in four different forms (disc cutting, baton cutting, cubing and shredding) and samples were taken in every point of their processing line. The unit operations were: peeling, cutting and washing with chlorinated water and also retention during 7 days storage was evaluated. The results showed that the initial unit operations (mainly peeling) influence the polyacetylene retention. This was attributed to the high polyacetylene content of their peels. In most cases, when washing was performed after cutting, less retention was observed possibly due to leakage during tissue damage occurred in the cutting step. The relatively high retention during storage indicates high plant matrix stability. Comparing the behaviour of polyacetylenes in the two vegetables during storage, the results showed that they were slightly more retained in parsnips than in carrots. Unit operations and especially abrasive peeling might need further optimisation to make them gentler and minimise bioactive losses.     

Comparison of calcium lactate with chlorine as a washing treatment for fresh‐cut lettuce and carrots: quality and nutritional parameters

The efficacies of calcium lactate and chlorine washing treatments of fresh‐cut lettuce and carrots were compared during storage at 4 °C over 10 days. The gas composition of packages, colour, enzyme activity, texture, sensory attributes, microflora and levels of ascorbic acid and carotenoids were evaluated at 1, 3, 7 and 10 days. Calcium lactate treatment was not significantly different to chlorine treatment (p < 0.05) in terms of maintaining colour, texture and acceptability of fresh‐cut lettuce and carrots during the entire storage period. The washing treatments did not affect levels of ascorbic acid of fresh‐cut lettuce or carrots. Carotenoid levels were higher in calcium lactate‐treated carrots than chlorine‐treated samples at the end of storage. Mesophilic, psychrotrophic and lactic acid bacteria counts were not significantly different between treatments for both vegetables. Copyright © 2005 Society of Chemical Industry     

唐山地区韭菜农药残留检测分析及膳食摄入风险评估

为了解唐山地区流通韭菜的农药残留状况与民众的膳食摄入风险,该研究采用高效液相色谱-串联质谱仪(HPLC-MS/MS)和气相色谱仪(GC)对2020年在唐山地区采集的415个韭菜样品分别进行了68种农药残留定性定量检测,并对韭菜样品中检出的农药进行风险评估.结果 表明,415个韭菜样品共计检出41种农药残留,检出率为69...     

Analysis of six fungicides and one acaricide in still and fortified wines using solid-phase microextraction-gas chromatography/tandem mass spectrometry

A multiresidue gas chromatographic method for the determination of six fungicides (captan, chlorthalonil, folpet, iprodione, procymidone and vinclozolin) and one acaricide (dicofol) in still and fortified wines was developed. Solid-phase microextraction (SPME) was chosen for the extraction of the compounds from the studied matrices and tandem mass spectrometry (MS/MS) detection was used. The extraction consists in a solvent free and automated procedure and the detection is highly sensitive and selective. Good linearity was obtained with correlation coefficients of regression (R²) > 0.99 for all the compounds. Satisfactory results of repeatability and intermediate precision were obtained for most of the analytes (RSD ? 20%). Recoveries from spiked wine ranged from 80.1% to 112.0%. Limits of quantification (LOQs) were considerably below the proposed maximum residue limits (MRLs) for these compounds in grapes and below the suggested limits for wine (MRLs/10), with the exception of captan.     

Pesticide residues in field‐sprayed and processed fruits and vegetables

This study was initiated to determine what residues of six insecticides (organochlorine, organophosphorus and pyrethroids) and four dithiocarbamate fungicides remained on raw agricultural commodities after harvest and to study the effect of the subsequent commercial processing on the residues. Sprayed crops of tomatoes, red peppers, asparagus, spinach, artichokes and peaches harvested after controlled field trials contained residues well below the maximum residue levels, except for lindane in tomatoes and acephate in artichoke. Commercial processing procedures led to large reductions in residue levels in the finished products. Washing removed all residual lindane, chlorpyrifos and cypermethrin from tomatoes. Chlorpyrifos residues were reduced by 67% during wood‐fire roasting of peppers, and subsequent peeling removed all the remains. Peeling and blanching of asparagus reduced chlorpyrifos concentrations to undetectable levels. Processing of artichokes eliminated acephate and chlorpyrifos after blanching. Acephate in peaches survived successive processing steps until the final heat process that destroyed remaining residues. The net results can contribute to assure the consumer of a safe wholesome food supply. Copyright © 2004 Society of Chemical Industry     

Effects of UV-C,red light and sun light on the carotenoid content and physical qualities of tomatoes during post-harvest storage

Mature-green (breaker-stage) tomatoes were harvested and treated daily with short bursts of UV-C, red light or sun light for up to 21 days. Control untreated tomatoes were kept in the dark for the same period. The effects of the treatments on the levels of the major tomato carotenoids, skin colour, tissue firmness and total soluble refractive solids were evaluated throughout storage. Results indicated that the concentration of lycopene in tomato exocarp was significantly increased after 4 days and dramatically enhanced by UV-C or red light treatments. However, the concentration of β-carotene was not affected by UV-C or red light treatments, and decreased by sun light treatment during 21 days of storage, compared to the control samples. The colour (a∗ and b∗ values) and force required to penetrate the tomatoes was, to a small but significant extent, influenced by the light treatments. However, the total soluble refractive solids of all tomato samples remained the same throughout storage. The findings reported here could be employed to improve tomato nutritional qualities lycopene content without inducing significant changes to the physical properties of tomatoes during post-harvest storage.     

Effect of controlled atmosphere storage, modified atmosphere packaging and gaseous ozone treatment on the survival of Salmonella Enteritidis on cherry tomatoes

In recent years, outbreaks of infections associated with raw and minimally processed fruits and vegetables have been reported. The objective of this study was to analyse the growth/survival of Salmonella Enteritidis at spot-inoculated or stem-injected cherry tomatoes during passive modified atmosphere packaging (MAP), controlled atmosphere (CA) and to compare the results with those of air storage at 7 and 22 degrees C. During MAP, the gas composition equilibrated to 6% O2/4% CO2. CO2 level was maintained as 5% through the term of CA storage at 7 and 22 degrees C. The results demonstrate that S. Enteritidis can survive and/or grow during the storage of tomatoes depending on the location site of the pathogen on fruit, suspension cell density and storage temperature. During MAP, CA and air storage, S. Enteritidis with initial population of 7.0 log10 cfu/tomato survived on tomato surfaces with an approximate decrease of 4.0-5.0 log10 cfu/tomato in population within the storage period; however, in the case of initial population of 3.0 log10 cfu/tomato, cells died completely on day 4 during MAP storage and on day 6 during both CA and air storage. The death rate of S. Enteritidis on the surfaces of tomatoes that were stored in MAP was faster than that of stored in air and in CA. Storage temperature was effective on the survival of S. Enteritidis for the samples stored at ambient atmosphere; cells died completely on day 6 at 7 degrees C and on day 8 at 22 degrees C. Stem scars provided protective environments for Salmonella; an approximate increase of 1.0 log10 cfu/tomato in stem-scar population was observed during MAP, CA and air storage at 22 degrees C within the period of 20 days. Cells survived with no significant change in number at 7 degrees C. During the research, the effect of ozone treatment (5-30 mg/l ozone gas for 0-20 min) was also considered for surface sanitation before storage. Gaseous ozone treatment has bactericidal effect on S. Enteritidis, inoculated on the surface of the tomatoes and can be used for surface sanitation of S. Enteritidis on tomatoes before storage at different conditions. Ten mg/l ozone gas treatment with different time intervals of 5 and 15 min was found to be effective respectively on low and high dose inoculum levels of S. Enteritidis attached for 1 h. Another variable considered during ozone treatment was the 4 h attachment time.     

Variability in captan residues in apples from a Canadian orchard

Apple trees in an orchard in Quebec, Canada were treated, following label directions, with the fungicide captan (1,2,3,6-tetrahydro-N-(trichloromethylthio)phthalimide) during the 2003 agricultural season. A total of 142 apples from three rows of trees were selected for determination of captan by GC/MS. Individual apples were found to contain captan levels ranging from 16.9 to 6350 ng g^-1. Only two individual apple samples exceeded the Canadian maximum residue limit (5000 ng g^-1) for captan in apples. Six composite samples, comprising half portions of eight individual apples, were analysed from each of the three experimental rows. Composite samples ranged in concentration from 166 to 2620 ng g^-1. The greatest uncertainty associated with the measured concentrations was due to variability among apples rather than the measurement of residue levels.