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.

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The present investigation was undertaken to study the effect of treatments and packaging on the quality of dried carrot slices during storage. Carrot cultivar 'Nantes' was sliced into 4.5 mm thick slices which were blanched in water at 95°C for 4 min followed by dipping in 6% potassium metabisulphite (KMS) solution for 40 min and 350 ppm potassium sorbate solution for 10 min prior to two stage phase drying i.e. at 90±5°C for 2 h and further drying at 60±5°C for 7 h in a cross-flow hot air cabinet dryer. The dried carrot slices were packed in 50 g packages of aluminium foil laminate (AFL) (polyethylene, aluminium foil and polyester) and high density polyethylene (HDPE) pouches having 32.5 μm and 56.0 μm thickness respectively and stored under ambient conditions i.e.18.5-29.1°C temperature and 44.4-60.4% relative humidity for 6 months. Significant (p≤0.05) increase was observed in the moisture content, water activity, reducing sugars and non-enzymatic browning while total solids, total soluble solids, titratable acidity, ascorbic acid, total sugars, pectin, rehydration ratio, sulphur dioxide, sorbic acid and carotenoids decreased significantly (p≤0.05) during storage. Carrot slices pretreated with 6% KMS and packed in AFL pouches were found to retain best physico-chemical quality. The curried product and soup prepared from dried slices from the same had highly acceptable sensory quality with initial overall acceptability scores 8.2 and 8.5 for curried slices and soup respectively on 9-point hedonic scale. The overall acceptability scores decreased from 8.2 to 7.9 and 8.5 to 7.7 in curried product and soup respectively after 6 months storage. All the samples were microbially safe during 6 months of storage.

Most of the schedules suggested by researchers for irrigating wheat (Triticum aestivum L. em Thell) are not sufficiently simple to be adopted by farmers in general. Recently a more practicable approach based on the ratio of a fixed amount of irrigation water (IW) to pan evaporation, PAN‐E, (cumulative evaporation from US Weather Bureau class A pan less rain since previous irrigation) has been suggested. Several workers have advocated irrigation of wheat at definite growth stages. One possibility of further improving the water use efficiency could be a combination of these two approaches. We compared, in a two year field study, IW/PAN‐E ratios of 0.75 and 0.9 for scheduling irrigation to winter wheat irrespective of growth stage with (i) a combination of these ratios with growth and (ii) irrigation at five growth stages. IW/PAN‐E of 0.75 irrespective of growth stage produced as much grain yield as irrigation at five growth stages. But the former, as an average, received 12 cm less irrigation. There was no gain in the yield by combining the IW/PAN‐E with growth stages. These results indicate that irrigating wheat, sown after a presowing irrigation, on the basis of IW/PAN‐E, irrespective of growth stage, offers a practical means to economize irrigation water without reduction in yield.

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