Effect of packaging and storage temperature on the survival of Listeria monocytogenes inoculated postprocessing on sliced salami

• Published in: Journal of food protection 2007-10, Vol.70 (10), p.2313-2320
• Main Authors: Gounadaki, A.S, Skandamis, P.N, Drosinos, E.H, Nychas, G.J
• Format: Article
• Language: English
• Subjects: aerobic conditions; ambient temperature; bacterial contamination; Biological and medical sciences; Colony Count, Microbial; Consumer Product Safety; food contamination; Food Contamination - analysis; Food Handling - methods; Food industries; Food Microbiology; food packaging; Food Packaging - methods; food pathogens; food storage; Fundamental and applied biological sciences. Psychology; General aspects; Handling, storage, packaging, transport; Humans; kinetics; Listeria monocytogenes; Listeria monocytogenes - growth & development; mathematical models; Meat Products - microbiology; microbial activity; Oxygen - metabolism; predictive microbiology; Risk Assessment; salami; shelf life; slicing; storage temperature; storage time; Temperature; Time Factors; Vacuum; vacuum packaging
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-70.10.2313

The survival of postprocess Listeria monocytogenes contamination on sliced salami, stored under the temperatures associated with retail and domestic storage, was investigated. Sliced salami was inoculated with low and high concentrations of L. monocytogenes before being packaged under vacuum or air. Survival of L. monocytogenes was determined after storage of sausages for 45 or 90 days for low or high sample inocula, respectively, at 5, 15, and 25 degrees C. All survival curves of L. monocytogenes were characterized by an initial rapid inactivation within the first days of storage, followed by a second, slower inactivation phase or "tailing." Greater reduction of L. monocytogenes was observed at the high storage temperature (25 degrees C), followed by ambient (15 degrees C) and chill (5 degrees C) storage conditions. Moreover, vacuum packaging resulted in a slower destruction of L. monocytogenes than air packaging, and this effect increased as storage temperature decreased. Although L. monocytogenes numbers decreased to undetectable levels by the end of the storage period, the time (in days) needed for this reduction and for the total elimination of the pathogen decreased with high temperature, aerobic storage, and high inoculum. Results of this study clearly indicated that the kinetics of L. monocytogenes were highly dependent on the interaction of factors such as storage temperature, packaging conditions, and initial level of contamination (inoculum). These results may contribute to the exposure assessment of quantitative microbial risk assessment and to the establishment of storage-packaging recommendations of fermented sausages.