EFFECT OF COOKING ON VETERINARY DRUG RESIDUES IN FOOD .6. LASALOCID

The effect of heat on lasalocid in model solutions and as residues in food was investigated. The drug was found to be relatively stable to h eat in neutral and acid conditions but unstable in basic conditions as was demonstrated by stability experiments at 100 degrees C in simple aqueous buffers. Lasalocid was found stable at pH 5.5 and 7.0 but unst able at pH 10.0 with a half-life of 30 min. In sunflower cooking oil a t 180 degrees C lasalocid was not stable with a half-life of 15 min. I n food, lasalocid residues in tissue from treated chickens were stable to cooking in chicken muscle but unstable when egg was cooked. A lass of 59% was observed for the preparation of an omelet, and a 27% loss was observed for the preparation of scrambled egg. Only a small amount (<5%) of lasalocid came out of tissue with exuded juices or into the liquid used for cooking. Residues in raw tissue from treated chickens were found to be evenly distributed in edible muscle.