Fresher Under Pressure Scientific Research
SEAFOODS
High hydrostatic pressure treatment of finfish to inactivate Anisakis simplex
FM Dong, AR Cook, RP Herwig
Journal of Food Protection 2003 Oct;66(10):1924
Abstract
High hydrostatic pressure has been demonstrated to be a useful technique for
treating food to reduce the number of pathogenic organisms and to extend shelf
life. Most research in this area has focused on bacteria. However, a concern
in the sashimi (raw fish) industry is that nematode worms such as Anisakis
simplex occur naturally in cold-water marine fish. The objectives of this
research were to perform a pilot study to determine the effect of high hydrostatic
pressure on the viability of Anisakis simplex larvae, commonly found in king
salmon and arrowtooth flounder, and to evaluate the effects of high hydrostatic
pressure on the color and texture of the fish fillets. Pieces of fish (ca.
100 g per bag) containing 13 to 118 larvae were exposed to pressures of up
to 80,000 lb/in2 (552 MPa) for up to 180 s. The times and pressures required
to kill 100% of the larvae were as follows: 30 to 60 s at 60,000 lb/in2 (414
MPa), 90 to 180 s at 40,000 lb/in2 (276 MPa), and 180 s at 30,000 lb/in2 (207
MPa). For all salmon treatments that killed 100% of the larvae, a significant
increase in the whiteness of the flesh was observed. Although high hydrostatic
pressure was effective in killing A. simplex larvae in raw fish fillets, its
significant effect on the color and overall appearance of the fillet may limit
its application to the processing of fish for raw-fish markets.
High-Pressure Inactivation of Hepatitis A Virus within Oysters
K. R. Calci, G. K. Meade, R. C. Tezloff, and D. H. Kingsley
Applied and Environmental Microbiology, January 2005, p. 339-343, Vol. 71,
No. 1
Abstract
Previous results demonstrated that hepatitis A virus (HAV) could be inactivated
by high hydrostatic pressure (HHP) (D. H. Kingsley, D. Hoover, E. Papafragkou,
and G. P. Richards, J. Food Prot. 65:1605-1609, 2002); however, direct evaluation
of HAV inactivation within contaminated oysters was not performed. In this
study, we report confirmation that HAV within contaminated shellfish is inactivated
by HHP. Shellfish were initially contaminated with HAV by using a flowthrough
system. PFU reductions of >1, >2, and >3 log10 were observed for 1-min treatments
at 350, 375, and 400 megapascals, respectively, within a temperature range
of 8.7 to 10.3°C. Bioconcentration of nearly 6 log10 PFU of HAV per oyster
was achieved under simulated natural conditions. These results suggest that
HHP treatment of raw shellfish will be a viable strategy for the reduction
of infectious HAV.
Sensitivity of Vibrio Species in Phosphate-Buffered Saline and in Oysters to High-Pressure Processing
DW Cook
Journal of Food Protection: Vol. 66, No. 12, pp. 2276–2282.
Abstract
Multiple strains of Vibrio vulnificus, Vibrio parahaemolyticus,
and Vibrio cholerae non-O1 were tested in phosphate-buffered saline
for their sensitivity to high-pressure processing (HPP). Variability in sensitivity
among strains was observed for all species; this variability decreased at
higher pressures. V. vulnificus was the species that was most sensitive
to treatment at 200 MPa (decimal reduction time [D] = 26 s), and V. cholerae
was the species that was most resistant to treatment at 200 MPa (D = 149 s).
The O3:K6 serotype of V. parahaemolyticus was more resistant to pressure
than other serotypes of V. parahaemolyticus were. The results of
studies involving V. vulnificus naturally occurring in oysters revealed
that a pressure treatment of 250 MPa for 120 s achieved a >5-log reduction
in the levels of this bacterium. V. parahaemolyticus serotype O3:K6
in oysters required a pressure of 300 MPa for 180 s for a comparable 5-log
reduction. When properly applied, HPP can be effective in improving the safety
of shellfish with respect to Vibrio spp.