Synergistic effect of high hydrostatic pressure, allyl isothiocyanate, and acetic acid on the inactivation and survival of pathogenic Escherichia coli in ground chicken

Abstract

Meat and poultry are prone to contamination with foodborne pathogens sourced from the livestock or introduced from the processing environments. In this study, for retention of meat quality while assuring microbial food safety, mild levels of high hydrostatic pressure were hurdled with food-grade additives (i.e., allyl isothiocyanate [AITC] and acetic acid [AA], functioned as antimicrobials) to inactivate pathogenic Escherichia coli in ground chicken. The reductions of Shiga toxin-producing E. coli (STEC) O157:H7 and uropathogenic E. coli (UPEC) were described as a function of high hydrostatic pressure (200-350 MPa), process-holding time (10-25 min), AITC concentration (0.05-0.20% w/w), and AA concentration (0.10--0.30% w/w) using a full factorial design. The antimicrobials had little influence on bacterial inactivation without high pressure. Without the antimicrobials, a high-pressure treatment at 300 MPa and 4°C for 15 min reduced E. coli O157:H7 and UPEC by 1.52 and 2.52 log, respectively. A 5-log reduction was achieved when AITC and AA were combined with high pressure, indicating a synergistic effect. The survivors were further reduced to below the detection limit of 1 log CFU/g after subsequent storage tests at 4 and 10°C for 10 days. The STEC O157:H7 was found slightly more resistant than UPEC in our test matrix. The developed models showed good fits with experimental data (R² > 0.95 for linear models; Pr > F (<0.0001) for dimensionless nonlinear models); which may help processors find/optimize the processing parameters to achieve target foodborne pathogens reduction for food safety requirement. PRACTICAL APPLICATION: Models were developed to predict the inactivation of pathogenic Escherichia coli in ground chicken by high-pressure processing (HPP) in combination with natural antimicrobial compounds. These models can be used to estimate/determine the HPP operation parameters and antimicrobial usage levels (i.e., allyl isothiocyanate and acetic acid) needed to achieve a specific microbial log reduction within the selected factor ranges. The operation parameters and clean-label ingredients are of interest in the food industry, which may benefit from the application of the models in achieving microbial safety, process optimization, and operation cost reduction.

Keywords: Escherichia coli O157:H7; essential oils; high-pressure processing; modeling; organic acids; uropathogenic Escherichia coli.