EFFECTS OF COMBINED ELECTRON-BEAM IRRADIATION AND SOUS-VIDE TREATMENTS ON MICROBIOLOGICAL AND OTHER QUALITIES OF CHICKEN BREAST MEAT

The microbiological safety, refrigeration shelf-life, and nutritional quality of chicken breast meat were investigated following combined el ectron-beam irradiation and cooking under vacuum (sous-vide). Chicken breast meat inoculated with 10(6) CFU/g of Listeria monocytogenes was irradiated with an electron beam at doses up to 3.1 kCy under vacuum i n barrier bags, cooked in a boiling water bath for 3 min 45 s (previou sly determined to achieve an internal temperature of 71.1 degrees C), and stored at 8 degrees C for up to 5 weeks. Listeria was undetectable in samples treated with combined sous-vide and irradiation at 3.1 kGy , but the organism survived the sous-vide treatment without irradiatio n and multiplied during storage. A similar study, conducted with unino culated chicken breast meat, revealed that the product which received both irradiation (3 kGy) and sous-vide treatment had a shelf-life of a t least 8 weeks at 8 degrees C, whereas the unirradiated samples treat ed sous-vide spoiled in 16 days. Listeria was undetectable in combinat ion treated samples, but some of the unirradiated sous-vide samples te sted after long storage showed high levels of Listeria. Some loss of t hiamine occurred with the combined treatments.