Submitted to: Journal of Food Processing and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/25/2013
Publication Date: 7/12/2013
Citation: Khosravi, P., Silva, J., Sommers, C.H., Sheen, S. 2013. Thermal inactivation of non-0157:H7 Shigatoxin producing Escherichia coli(STEC) on catfish fillets. Journal of Food Processing and Technology. http://dx.doi.org/10.4172/2157-7110-S11-006. Interpretive Summary: The non-O157:H7 Shiga toxin-producing Escherichia coli strains, especially the Big 6 (identified by FSIS for ground beef), are attracting more attention due to their potential to cause food hazards. Thermal treatment is one of the most commonly used intervention methods to reduce or eliminate the foodborne pathogen risks in foods. In this report, the thermal destructive parameters interns of D and Z values for microbes were established and will assist the risk assessment to enhance catfish and/or other finfish safety.
Technical Abstract: Non-O157:H7 Shiga toxin-producing Escherichia coli (non-O157 STEC) strains have emerged as foodborne pathogens caused numerous foodborne illness outbreaks worldwide. Seafood (fish) consumption has significantly increased in recent years and it could be more common for STEC outbreaks due to non-O157 strains with seafood products. However, published data on thermal inactivation in fish (e.g. catfish) are still lacking and not yet established. In this study catfish fillets were inoculated with a six-serovar cocktail of non-O157 STEC serovars, i.e. O26:H11, O45:H2, O103:H2, O111:NM, O121H19, and O145:RM (the Big 6), to determine the impact of thermal treatment (heat) on their survival and thermal inactivation kinetics. The inoculated catfish fillets (10^8-9 or billions cfu/g) were subjected to isothermal heating at 55, 60, and 65 degree C. The D- and z- values were determined by using the linear regression of the survival experiment data. The D- values were 712 (R-square = 0.88), 38.8 (R-square = 0.97) and 3.6 (R-square = 0.91) seconds at 55, 60 and 65 degree C, respectively. The z-value was 4.4 degree C, which is consistent with the reported values for STECs in other food products. The results of this study showed that the thermal inactivation effect of non-O157 STECs is not the same as of O157 strains in catfish meat, especially at lower temperature (e.g. 55 degree C). The findings will assist risk assessors in providing safer finfish products to consumers.