Radiossensibilidade de esporos de Paenibacillus larvae subsp. larvae em mel Sensitivity radiation of spores of Paenibacillus larvae subsp. larvae in honey

This research has investigated the efficacy of gamma radiation in inactivating spores of Paenibacillus larvae subsp. larvae that causes the “American foulbrood disease”, a highly contagious disease still exotic in Brazil that kills bees and contaminates honey, preventing its commercialization. Samples of 60 g of two types of honey contaminated with 3,5x10 3 spores/mL concentrations of that microorganism were gamma irradiated to doses of 0, 5, 7.5, 10, 12.5 and 15 kGy and then counted for spores of P. larvae. The analyses indicated reductions of 97,0±1,2% and 98,3±0,5% in the number of active spores for a 5 kGy dose, the higher figure corresponding to the honey with lower consistency. Doses equal to 7.5 kGy or higher yielded no active spores 9 the detection threshold was 5.5 spores/mL). Finally, the corresponding values for D 10 (approximately 3 kGy) and the fractions of inactivated spores for the two types of honey were determined as functions of the radiation dose.