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United States Department of Agriculture

Agricultural Research Service

Research Project: ALTERNATIVE FOOD PROCESSING TECHNOLOGIES

Location: Food Safety and Intervention Technologies

Title: Growth of non-0157:H7 shiga-toxin producing Escherichia coli on catfish fillets

Authors
item Khosravi, Parvaneh
item Silva, Juan -
item Sommers, Christopher
item Sheen, Shiowshuh

Submitted to: Journal of Food Processing and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 27, 2013
Publication Date: June 20, 2013
Citation: Khosravi, P., Silva, J., Sommers, C.H., Sheen, S. 2013. Growth of non-0157:H7 shiga-toxin producing Escherichia coli on catfish fillets. Journal of Food Processing and Technology. http://dx.doi.org/10.4172/2157-7110.S11-004.

Interpretive Summary: Seafood is associated with foodborne illness outbreaks more than meat or produce when adjusted for average annual consumption. Shiga-toxin producing Escherichia coli (STECs)are emerging foodborne pathogens which have caused foodborne illness outbreaks on a global basis, with many different food products, including fish. In this study the growth patterns of a multi-isolate cocktail of STECs inoculated onto catfish fillets and stored at various temperatures was determined and modeled. There was no STEC growth at 4 deg C, however, the STECs grew at 10, 15, 20 and 30 deg C in a temperature dependent manner, with higher growth rates being associated with higher temperatures. The results of this study provide information to risk assessors regarding the growth potential of the STECs on aquaculture-raised fish using catfish as a model system. .

Technical Abstract: Shiga-toxin producing Escherichia coli (STECs) are emerging pathogens which have been involved in numerous foodborne illness outbreaks. In this study the ability of a multi-isolate cocktail of STEC serovars O26:H11, O45:H2, O103:H2, O111:NM, O121:H19, and O145:RM to grow on catfish fillets at refrigeration and abuse temperatures was investigated. Catfish fillet samples (10 g) were inoculated with the STEC cocktails to ca. 3 log CFU/g and incubated under aerobic conditions for up to 120 h. There was no STEC growth at 4 deg C, however, the STECs grew at 10, 15, 20 and 30 deg C in a temperature dependent manner, with higher growth rate being associated with higher temperatures. Lag phase ranged from 15h at 10 deg C to 1.75 h at 30 deg C. Exponential phase growth rates ranged from 0.03 log CFU/g/h at 10 deg C to 0.65 log CFU/g/h at 30 deg C. Growth curves constructed using ComBase DMfit provided a good statistical fit to the observed data, resulting in a high correlation coefficient (R2) of 0.98. The results of this study provide information to risk assessors regarding the growth potential of the STECs on aquaculture-raised fish using catfish as a model system.

Last Modified: 8/22/2014
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