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Davis College of Agriculture, Natural Resources and Design


Division of Animal and Nutritional Sciences


The efficacy of hops beta acids (HBA) against unstressed and stress-adapted Listeria monocytogenes in ham extract and the consumers’ acceptability of HBA on ready-to-eat (RTE) hams were investigated. Unstressed or 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 pathogen during storage (7.2°C, 26 days) was monitored periodically. Sensory evaluation (30 participants, 9-point hedonic scale) was performed with hams dipped into 0.05, 0.11, and 0.23% HBA solution. Ham extracts without HBA supported rapid growth of unstressed and stress-adapted cells with growth rates of 0.39–0.71 log CFU/mL/day and lag phases of 0–3.26 days. HBA inhibited growth of unstressed L. monocytogenes by slowing () growth rate (0.24–0.29 log CFU/mL/day) and increasing () length of the lag phase (3.49–12.98 days) compared to control. Acid-, cold-, or starvation-stress-adapted cells showed cross protection against HBA with greater () growth rates (0.44–0.66 log CFU/mL/day) and similar or shorter lag phases (0–5.44 days) than unstressed cells. HBA did not () affect sensory attributes of RTE ham. These results are useful for RTE meat processors to develop operational protocols using HBA to control L. monocytogenes.

Source Citation

Wang, L., & Shen, C. (2015). Survival of Unstressed and Acid-, Cold-, and Starvation-Stress-AdaptedListeria monocytogenesin Ham Extract with Hops Beta Acids and Consumer Acceptability of HBA on Ready-to-Eat Ham. BioMed Research International, 2015, 1–9.


Copyright © 2015 Li Wang and Cangliang Shen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.



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