|Chien, Shih-yung - National Taiwan University|
|Sheen, Lee-yan - National Taiwan University|
Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2016
Publication Date: 6/14/2016
Citation: Chien, S., Sheen, S., Sommers, C.H., Sheen, L. 2016. Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol. Frontiers in Microbiology. 7(920):1-11.
Interpretive Summary: High pressure processing (HPP), is a green and sustainable non-thermal means to reduce the levels of harmful bacteria in foods, and has been demonstrated to be an effective method for inactivating pathogenic Escherichia coli. Natural antimicrobial compounds are “consumer friendly” and can help sensitize E. coli to the HPP treatment. In this study the ability of HPP to inactivate the intestinal pathogenic E. coli O157:H7 versus Uropathogenic E. coli (UPEC) commonly found in chicken meat, with and without thymol essential oil as a natural antimicrobial, were determined. Mathematical models to predict E. coli inactivation based on HPP, thymol concentration, and process time were developed. These models will help poultry processors achieve a 5 log reduction (100,000 E. coli/g of meat) and provide regulatory agencies with valuable information for the control of E. coli O157:H7 and UPEC in ground chicken meat.
Technical Abstract: Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compare the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) with and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than O157:H7 at 450MPa and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300-400 MPa), thymol concentration (100-200 ppm), and pressure-holding time (10-20 min) on the inactivation of E. coli O157:H7 and UPEC in ground chicken. The quadratic equations were developed to predict the impact on E. coli O157:H7 (R2 = 0.94) and UPEC (R2 = 0.98), as well as dimensionless nonlinear models. Both linear and non-linear models were validated with data obtained from separated experiment points. The results provide useful information of both E. coli O157:H7 and UPEC in regard to how they may survive HPP in the presence and absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of E. coli O157:H7 and UPEC in ground chicken.