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Under a multicentre study conducted by the Indian Council of Medical Research, 2205 samples of dairy milk were collected from rural and urban areas of 12 states representing different geographical regions of India. These samples were analysed for residues of DDT and different isomers of HCH by gas-liquid chromatography. Analytical quality assurance between various participating laboratories was ensured through analysis of check samples. The residues of DDT and HCH were detected in more than 80% of samples analysed. Concentrations of DDT residues, alpha-HCH, beta-HCH, gamma-HCH and delta-HCH exceeded their maximum residue limits prescribed by the Ministry of Health and Family Welfare of the Indian Government in 37, 21, 42, 28 and 4% of the samples, respectively. Median values of DDT and HCH found in dairy milk in India were more than the corresponding values reported from most other countries. The results showed significant variations in the incidence as well as level of these contaminants in dairy milk from different regions of the country.

A method has been developed for determining carbaryl (1-naphthyl N-methyl carbamate) in grains, based on hydrolysis of carbaryl with methanolic potassium hydroxide to 1-naphthol, reaction with 4-aminophenazone in the presence of alkaline oxidizing agent, and spectrophotometric measurement at the absorption maximum at 475 nm. The relationship between absorbance and concentration is linear in the range of 0.5-20 μg/mL. The method can be applied to levels as low as 0.3 ppm carbaryl in grains.

Ochratoxin A (OTA), a secondary metabolite produced by the species of Aspergillus and Penicillium has been found to be nephrotoxic, immunosuppressive and teratogenic in many species and is a possible human carcinogen. Its prevalence in cereals, namely wheat and barley, has been reported from many European countries. In this study, 126 samples of wheat and barley collected from different regions in India were analyzed by high‐performance liquid chromatography for the presence of OTA. The highest OTA content determined in one sample of wheat was 2.3 µg/kg. None of the 126 samples of wheat and barley contained more than 5 µg/kg. Wheat (82.6%) and barley (90%) samples contained less than 0.1 µg/kg, which is the limit of quantification of OTA in this study. The maximum limit of OTA for wheat, barley and rye that is being debated at Codex Alimentarius Commission meetings is 5 µg/kg. In an attempt to determine if there was any correlation between the ochratoxigenic mold mycoflora and the ochratoxin content in the samples analyzed, enumeration of the molds that belonged to Aspergillus and Penicillium species was determined using general mycological media. The aflatoxigenic and ochratoxigenic mycoflora was also enumerated using selective agar media. It was observed that more aflatoxigenic molds were recovered in both wheat and barley samples. None of the species of Penicillium detected from the samples was found to be ochratoxigenic. However, Aspergillus species belonging to section Nigri, Aspergillus niger group, also an ochratoxin producer, were recovered from the samples.

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