Inactivation of extraintestinal pathogenic E. coli suspended in ground chicken meat by high pressure processing and identification of virulence factors which may affect resistance to high pressure

Extraintestinal pathogenic Escherichia coli (ExPEC) are responsible for urinary tract infections, inflammatory bowel disease, sepsis and meningitis. Retail poultry meat has been identified as the main reservoir for ExPEC in food. Information regarding ExPEC virulence factor (VF) or antibiotic resistance (AR) involvement with resistance to high-pressure inactivation in food is lacking. In this study we inoculated ground chicken meat with 22 individual isolates of clinical uropathogenic E. coli (UPEC) and newborn meningitis causing E. coli (NMEC), and isolates from retail chicken meat. We then determined their high-pressure inactivation kinetics (D10-value). The mean D10-value for all isolates (n = 22) was 3.26 min at 400 MPa. The mean D10-value for the UPEC, NMEC, chicken isolates were 5.0, 1.3, 2.23 and 4.98 min at 400 MPa, respectively. The D10 varied widely between the 22 isolates. The mean D10-value for the clinical isolates was 3.33 vs. 3.15 for the non-clinical isolates. The NMEC strains were more sensitive to HPP. ExPEC lacking chuA, cnf1, sinH, papG, hlyA, vat, yncD were more resistant to HPP, indicating ExPEC VF could play a role in high pressure resistance. HPP at 600 MPa for 3 min resulted in >6 log10 reductions for UPEC, NMEC, and retail chicken product isolates. •HPP D10 were 5, 1.3, 2.23 and 4.98 mins at 400MPa for UPEC, NMEC, CM, and CS isolates.•HPP at 600 MPa for 3 min inactivated > 6 log CFU/g of all ExPEC types•Multiple ExPEC virulence factors may affect HPP resistance.•Antibiotic resistance did not affect HPP resistance