The uptake and degradation of pirimiphos-methyl by Stilton cheese

Abstract

Two Stilton cheeses were placed on a wooden plank treated with 14C-ring-labelled pirimiphos-methyl at 440 mg/m 2. One cheese was in direct contact with the treated surface, the other was separated from the surface by the addition of a layer of cheese cloth. Samples taken on alternate days showed that contamination had penetrated into the outer 10 mm of the cheese in contact with the treated surface. The pirimiphos-methyl was mostly confined to the outer 6 mm where the level rose to about 10 ppm after 5 days, but the mean value showed little increase during the remaining 44 days exposure. Contamination of the cheese separated from the surface by a layer of cheese cloth was confined to the outer 8 mm. The uptake in this case was much slower, rising to a maximum of about 8 ppm towards the end of the experiment. The penetration of the pirimiphos-methyl into the plank was also examined.