Two processing methods for the isolation of Salmonella from naturally contaminated alfalfa seeds

Two processing methods were examined for the recovery of Salmonella from na turally contaminated alfalfa seed. Seed samples, from each of three investi gations, were processed by sprouting and shredding before preenrichment and culture. In lot A, Salmonella serotype, Newport was isolated from 3 of 30 sample units with the sprouting method and 2 of 30 with the shredding metho d. In lot B, three serotypes in various combinations were isolated from 10 of 30 sample units with the sprouting method and 9 of 30 with the shredding method. In lot C, Salmonella group C, was isolated from 27 of 30 sample un its with the sprouting method and 24 of 30 with the shredding method. Addit ionally, serotype Newport was found in one lot C sample unit. Using shredde d seed data, a most probable number (MPN) for Salmonella contamination per lot was calculated. Serotype Newport was estimated at 0.07 MPN/100 g in lot A; the concentration for three serotypes was estimated to be 0.36 MPN/100 g in lot B; Salmonella group C, was estimated at 1.8 MPN/100 a in lot C. Ou r success in isolating Salmonella from alfalfa seeds was likely attributed to the volume of material tested and the quick acquisition of the seeds aft er the outbreak was identified. Shredding the seeds was easier and yielded definitive results more quickly than sprouting.