Effect of gamma radiation on the microbiological quality of seeds and seed sprouts

Irradiation (2 kGy) treatment alone or in combination with a decontamination wash regime using calcium hypochlorite, eugenol (oil of clove) or oregano oil did not significantly affect the quality of alfalfa seeds during sprouting. Irradiation (2 kGy) and oregano oil (0.1%) did result in significantly lower total counts during storage of the sprouts for 5 days at 5 deg C. However, the microbial counts in all cases were > log 8 by day 5 of storage and all the samples appeared spoiled. Pantoea spp. was the dominant bacterium present in all samples. These results suggest that even if the initial microbial quality of the seeds is good (< 1 log/g) sufficient microorganisms are present to grow rapidly during the sprouting process, resulting in sprouts with high total counts. (author)