Modeling the survival of Escherichia coli O157:H7 under hydrostatic pressure, process temperature, time and allyl isothiocyanate stresses in ground chicken

Authors: HUANG, CHI-YUN - National Taiwan University; Sheen, Shiowshuh - Allen; Sommers, Christopher; SHEEN, LEE YAN - National Taiwan University

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2018
Publication Date: 8/14/2018
Citation: Huang, C., Sheen, S., Sommers, C.H., Sheen, L. 2018. Modeling the survival of Escherichia coli O157:H7 under hydrostatic pressure, process temperature, time and allyl isothiocyanate stresses in ground chicken. Frontiers in Microbiology. Volume 9, Article 1871: 1-11. 10.3389/fmicb.2018.01871.
DOI: https://doi.org/10.3389/fmicb.2018.01871

Interpretive Summary: Escherichia coli O157:H7 is a foodborne pathogen responsible for serious illness. High pressure processing (HPP) kills bacteria by crushing them while allyl isothiocyanate (AITC) essential oil is a natural antimicrobial compound. A combination of HPP and AITC was used to kill E.coli O157:H7 in ground chicken meat, and the HPP + AITC combinations needed to kill 99.999% of E. coli O157:H7 were identified. Two types of mathematical models (linear and nonlinear) were developed and validated through an experiment design to predict how HPP and AITC work together to kill E.coli O157:H7. The mathematical models may be used to assist government and food industry lessen the risk of E. coli O157:H7 to consumers.

Technical Abstract: Shiga toxin-producing Escherichia coli O157:H7 (STEC O157:H7), a common contaminant in meat and poultry, was investigated for inactivation/lethality enhancement using the non-thermal High Pressure Processing (HPP) in combination with allyl isothiocyanate (AITC) essential oil as a sensitizer. The operation temperature was found an important factor (-15 to 4 deg C), affecting the inactivation of E. coli O157:H7. A full factorial experiment design (4 factors x 2 levels) was used to evaluate the effect of pressure (250-350MPa), operation temperature (-15 - 4 deg C), AITC concentration (0.05-0.15%, w/w), and pressure-holding time (10-20 min) on the inactivation of E. coli O157:H7 in ground chicken. The linear model (a polynomial equation) was developed to predict/describe those four parameters’ impact on E. coli O157:H7 survival (R2 = 0.90), as well as a dimensionless nonlinear model. Both types of models were validated with data obtained from separate experiment points. The dimensionless model also demonstrated that it may predict the lethality reasonably well with some factors set slightly outside the designed ranges (e.g. a wider application than the linear model). The results provide important information regarding the E. coli O157:H7 survival behavior affected by HPP (including hydrostatic pressure, process time and temperature) and added AITC. The storage test (at 4 and 10 deg C, 10 days) after HPP+AITC treatment further indicated that AITC may continue depressing or killing the pressure-damaged cells – a positive trend in microbial food safety concern. Regulatory agencies and food industry may use those models for E. coli O157:H7 risk assessment in ground chicken.