Savvaidis IN, Skandamis P, Riganakos KA, Panagiotakis N, Kontominas MG. Control of natural microbial flora and Listeria monocytogenes in vacuum-packaged trout at 4 and 10 degrees C using irradiation.
J Food Prot 2002;
65:515-22. [PMID:
11899050 DOI:
10.4315/0362-028x-65.3.515]
[Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of gamma irradiation on the natural microflora of whole salted vacuum-packaged trout at 4 and 10 degrees C was studied. In addition, the effectiveness of gamma irradiation in controlling Listeria monocytogenes inoculated into trout was investigated. Irradiation at doses of 0.5 and 2 kGy affected populations of bacteria, namely, Pseudomonas spp., Brochothrix thermosfacta, lactic acid bacteria, H2S-producing bacteria typical of Shewanella putrefaciens, and Enterobacteriaceae, at both 4 and 10 degrees C. This effect was more pronounced at the higher dose (2 kGy) and the lower temperature (4 degrees C). Pseudomonads, H2S-producing bacteria typical of S. putrefaciens, and Enterobacteriaceae showed higher sensitivity to gamma irradiation than did the rest of the microbial species. Sensory evaluation did not show a good correlation with bacterial populations. On the basis of sensory odor scores, a shelf life of 28 days (2 kGy, 4 degrees C) was obtained for salted vacuum-packaged freshwater trout, compared with a shelf life of 7 days for the unirradiated sample. Under the same conditions, the growth of L. monocytogenes inoculated into the samples was suppressed by 2 log cycles after irradiation (2 kGy) and storage for up to 18 days at 4 degrees C.
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