|Huang, Chi-yun - National Taiwan University|
|Chien, Shih-yung - National Taiwan University|
|Scullen, O - Butch|
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2018
Publication Date: 3/1/2018
Citation: Sheen, S., Huang, C., Ramos, R.V., Chien, S., Scullen, O.J., Sommers, C.H. 2018. Lethality prediction for Escherichia coli 0157:H7 and Uropathogenic E. coli in ground chicken treated with high pressure processing and trans-cinnamaldehyde. Journal of Food Science. 83(3):740-749.
Interpretive Summary: High hydrostatic pressure (or high pressure processing – HPP) and trans-cinnamaldehyde essential oil in combination was proved to be a feasible means to enhance microbial food safety with regard to Escherichia coli O157:H7 and Uropathogenic E. coli (UPEC). The interaction of HPP and antimicrobials may reduce the hydrostatic pressure needed to achieve a greater than 5 log (99.999%) cell count reduction or lethality, and reduce meat texture damage largely due to an excessive high pressure. Two types of models (linear and nonlinear) were developed and validated through an experiment design to predict the lethality which may be used to assist government and food industry in risk assessment tasks.
Technical Abstract: Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (Uropathogenic E. coli (UPEC)) are commonly found in many foods including chicken meat. In this study we compared the resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic pressure (HHP, also known as HPP – high pressure processing) and trans-cinnamaldehyde (an essential oil). UPEC was found slightly less resistant than O157:H7 in our test parameter ranges. With the addition of trans-cinnamaldehyde as an antimicrobial to meat, HPP lethality enhanced both O157:H7 and UPEC inactivation. To facilitate the predictive model development, a central composite design (CCD) was used to assess the three-parameter effects, i.e. pressure (300-400 MPa), trans-cinnamaldehyde dose (0.2-0.5%, w/w), and pressure-holding time (15-25 min), on the inactivation of E. coli O157:H7 and UPEC in ground chicken. Linear models were developed to estimate the lethality of E. coli O157:H7 (R2 = 0.86) and UPEC (R2 = 0.85), as well as dimensionless nonlinear models. All models were validated with data obtained from separated experimental points. Because linear models of O157:H7 and UPEC had similar R2 and the significant difference of CCD design point was only 9 in 20; all data were combined to generate model to include both O157 and UPEC. The results provide a useful information/tool to predict how pathogenic E. coli may survive HPP in the presence of trans-cinnamaldehyde and to achieve a greater than 5 log CFU/g reduction in real chicken meat. The models may be used for process optimization, product development and to assist the microbial risk assessment.