The effect of cooking on veterinary drug residues in food. Part 8. Benzylpenicillin.

The stability of benzylpenicillin to heat and cooking was studied. Stability of this compound in water (at 100 degrees C and 65 degrees C), 5% ethanol, 5% sodium bicarbonate, pH 5.5 buffer at 100 degrees C and in hot cooking oil at 140 degrees C and 180 degrees C was established. Benzylpenicillin was stable at 65 degrees C but not stable at higher temperatures with half-life times varying between 15 and 60 min in the solutions investigated. This drug was not stable to cooking, losses being proportional to the harshness of the cooking regime. Where fluids were released during the cooking process, sometimes over half of the residue passed from the solid tissue into the cooking medium.