Purpose: This study aims to investigate the efficacy of HBA against unstressed, or different stresses adapted L. monocytogenes in ham extract, and the consumers’ acceptability of HBA applied on RTE meats.
Methods: Unstressed, acid, cold, or starvation-stress adapted L. monocytogenes was inoculated (1.3 - 1.5 log CFU/ml) into 10% ham extract without (control) or with HBA (4.44 or 10.0 µg/ml). Survival/growth of the pathogens during storage (7.2°C, 26 days) was periodically monitored on tryptic soy agar plus 0.6% yeast extract and PALCAM. Sensory evaluations (30 participates, 9-point hedonic scale) were performed with ham, turkey breast and frankfurters dipped into 0.05, 0.11 and 0.23% HBA solution for 2 min. Data (2 repeats/3 samples per repeat) were analyzed using the mixed model procedure of SAS, DMFIT, and USDA-Integrated-Predictive-Modeling-Program software.
Results: Ham extracts without HBA (control) supported rapid growth of unstressed and stresses adapted cells with growth rate of 0.26 - 0.44 log CFU/ml/day and lag phase of 0 - 0.18 days. HBA inhibited unstressed L. monocytogenes growth by showing slower (P < 0.05) growth rate (0.24 - 0.29 log CFU/ml/day) and longer (P < 0.05) lag phase (3.49 - 12.98 days) than the control. Acid, cold, or starvation-stress adapted cells showed cross-protection to HBA with higher (P < 0.05) growth rate (0.44 - 0.71 log CFU/ml/day) and similar or shorter (P < 0.05) lag phase (0 - 5.44 days) than the unstressed cells. The HBA did not (P > 0.05) affect the sensory attributes of RTE meats.
Significance: Results should be useful for developing operation protocols of HBA to control L. monocytogenes during post-lethality processing of RTE meats.