Alfalfa Seed Germination and Yield Ratio and Alfalfa Sprout MicrobialKeeping Quality Following Irradiation of Seeds and Sprouts

AlfalfaSeed Germination and Yield Ratio and Alfalfa Sprout Microbial Keeping QualityFollowing Irradiation of Seeds and Sprouts

Journalof Food Protection: Vol. 64, No. 12, pp. 1988-1995.

KathleenT Rajkowski and Donald Wl Thayer

U.S.Department of Agriculture, Agricultural Research Service, Eastern RegionalResearch Center,

Abstract-Foods can be treated with gamma radiation, a nonthermalfood process, to inactivate foodborne pathogens and fungi, to kill insects on orin fruits and vegetables, and to increase shelf life. Gamma irradiation isespecially well suited for these treatments because of its ability to penetratecommercial pallets of foods. Irradiated fruits, vegetables, poultry, andhamburger have been received favorably by the public and are now available insupermarkets. The use of irradiation on fresh alfalfa sprouts was studied todetermine its effect on keeping quality as related to aerobic microbial load.After an irradiation dose of 2 kGy, the total aerobic count decreased from 105-8to 103-5 CFU/g, and the total coliform counts decreased from 105-8to 103-0 CFU/g. The results showed that the sprouts maintainedtheir structure after irradiation, and the keeping quality was extended to 21days, which is an increase of 10 days from the usual shelf life. The effect ofvarious doses of irradiation on alfalfa seeds as measured by percent germinationand yield ratio (wt/wt) of sprouts was determined. There was little effect onthe percent germination, but as the dose increased, the yield ratio of alfalfasprouts decreased. As the length of growing time increased, so did the yieldratio of the lower dose irradiated seeds (1 to 2 kGy). The irradiation processcan be used to increase the shelf life of alfalfa sprouts, and irradiatingalfalfa seeds at doses up to 2 kGy does not unacceptably decrease the yieldratio for production of alfalfa sprouts.