TITLE:
The Effects of Heat Shock on the D-Values of Listeria monocytogenes on Selected Seafood Matrices
AUTHORS:
Michael V. Wood, Aswathy Sreedharan, Rachael Silverberg, Alina N. Balaguero, Keith R. Schneider
KEYWORDS:
Listeria monocytogenes, Ready-to-Eat Seafood, Heat Shock, D-Value
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.8,
August
5,
2015
ABSTRACT: With more ready-to-eat foods and increased shelf-lives, prevention of Listeria monocytogenes contamination has
become a necessity for the food industry. This study examined the effects of sublethal
heat treatment on the decimal reduction time (D-values) of three L. monocytogenes serotypes (1/2a, 1/2b,
4c), and non-pathogenic L. innocua.
The D70 (D-value at 70℃) values of heat-shocked (HS) and
non-heat-shocked (NHS) Listeria grown
in tryptic soy broth (TSB) were determined. The D70 values of HS L. monocytogenes serotype 1/2a and L. innocua were
significantly higher compared to NHS cultures, although by 48 h, the values
returned to NHS levels. When HS and NHS 1/2a and 1/2b were inoculated on crab
meat and cooked shrimp, the D70 values of HS cultures were at least
2-fold higher, compared to when they were grown in TSB. This increase in heat
resistance for the HS cultures may be attributed to the protective effect of
the seafood matrix itself.