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EFFECTS OF LOW-DOSE GAMMA IRRADIATION ON THE BACTERIAL
MICROFLORA OF FRESHLY PICKED CRABMEAT
Yupin Chen, R.M. Grodner, L.S. Andrews
Department of Food Science
Louisiana Agricultural Experiment
Louisiana State University
Baton Rouge, LA 70803
ABSTRACT
Station
Low-dose gamma irradiation is used to reduce or eliminate
spoilage and pathogenic microorganisms that may contaminate
seafoods during processing. Pathogenic bacteria that have been
targeted for reduction or elimination in freshly picked blue crabmeat
include V. parahaemolyticus, Listeria monocytogenes, Staphylococcus
aureus, E. coli and other aerobic spoilage organisms.
Microbiological analyses were performed to enumerate the
surviving organisms in freshly picked crabmeat following treatment
with 0, 0.125, 0.25, 0.5, 0.75, 1.0, 1.5 and 2 kGy of gamma irradiation.
Both non-selective and selective media were used for enumeration of
spoilage and various pathogens on day 0, 7 and 14 of ice storage.
The results indicate that low-dose gamma irradiation
significantly reduced all microorganisms in crabmeat. The D-values,
calculated from linear regression analysis for specific bacterial
genera varied accordingly to each individual L. monocytogenes had the
highest D-value of 0.59 kGy and Vibrio parahaemolyticus had the
lowest of level of radiosensitivity among the microorganisms analyzed.
S. aureus had the D-value of 0.16 kGy. Gamma irradiation doses equal