REDUCTION IN SPIKED SULPHADIMIDINE LEVELS IN MILK BY COMMON STORAGE AND PROCESSING TECHNIQUES

Abstract

ABSTRACT Sulphadimidine (SDM) is widely used as antimicrobial as well as anticoccidial agents on food producing animals, and its violative residues in milk have been reported in many countries. Some common techniques of storage at 27 ± 2, 6 ± 2 and−18 ± 2C temperatures, and processing by heating, curd fermentation, acid coagulation, heat coagulation and spray drying investigated reduced the SDM residue levels in spiked milk to varying extents, but could not eliminate the residue completely. Reduction (P < 0.01) of the spiked SDM levels was enhanced by an increase in storage temperature, storage period, heating period as well as fermentation inoculum level in milk. There were significant (P < 0.01) losses in SDM caused by open as well as microwave heating, curd fermentation, curd storage at 6 ± 2C temperature, acid coagulation, heat coagulation and spray drying. Acid coagulation showed the highest residue reduction among all the methods studied. Heat coagulation by microwave heating showed significantly (P < 0.01) a greater reduction than open heating. Open as well as microwave heating two times with intermittent storage showed significantly (P < 0.01) greater residue reductions than a single time equal period heating. Some of the techniques could be satisfactorily followed to reduce the SDM residue in already contaminated milk less than the prescribed safe limit, ascertaining safe consumption of such milk without discarding it, and thus, having cost as well as nutritional implications in under-developed and developing countries. PRACTICAL APPLICATIONS Several sulphonamides are widely used as broad-spectrum antimicrobials and narrow anticoccidials in many countries in food-producing animals because of their relatively low cost and ease of administration. Their potential tumourgenesis, thyrotoxicity, genotoxicity, embryotoxicity, teratogenicity and hypersensitivity reactions are of much concern, as these show more residue violations than any other drug in many countries. The present study was undertaken for the purpose of eliminating the sulphadimidine (SDM) residue, or bringing its levels less than the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives recommended maximum residue limit (MRL) of 0.025 mg SDM/L milk. Results of the study indicated that the common processing and storage practices could significantly reduce the SDM residue level in spiked milk. This study would help us to utilize, without any appreciable health risk to the consumer, a batch of milk contaminated with the SDM residues more than the prescribed MRL for further processing without discarding it, especially in underdeveloped and developing countries.