Slight Temperature Deviation during a 56-Day Storage Period Does Not Affect the Microbiota of Fresh Vacuum-Packed Pork Loins

Abstract

It is profitable to export fresh meat overseas, where it is often regarded as a premium commodity. Meeting this demand for fresh meat, however, necessitates long export times, during which uncontrolled temperature increases can affect the microbiological quality of the meat and thereby, reduce shelf life or compromise food safety. To study the impact of temperature deviations on microbial community composition and diversity, we used 16S rRNA gene sequencing for Listeria monocytogenes and Salmonella spp. detection to describe the surface microbiota of eight batches of vacuum-packed loins stored at −1.5 °C (control) for 56 days and subjected to a 2 °C or 10 °C temperature deviation for a few hours (mimicking problems regularly encountered in the industry) at day 15 or 29. The presence of pathogens was negligible. The applied temperature deviations were not associated with different microbiota. Sequencing analysis showed the presence of Yersinia, an unexpected pathogen, and relative abundance increased in the groups subjected to temperature deviations. Over time, Lactobacillales_unclassified genus became the main constituent of the microbiota of vacuum-packed pork loins. Although the microbiota of the eight batches appeared similar at the beginning of storage, differences were revealed after 56 days, suggesting unequal aging of the microbiota.

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“…It was proved that in pork that was cooled in a refrigerator using washing without treatment with suspensions of lactic acid microorganisms (control group), lactic acid microorganisms dominated on the 4 th day of storage. The same pattern was found by C. Braley et al (2023) for storing pork in vacuum packaging on days 15 and 29 at a temperature regime of -1.5°C, which was changed according to production risks at 2°C or 10°C for several hours. However, in this case, the researchers note that in contrast to SafePro ® B-2 (Lactobacillus sakei) and SafePro ® B-SF-43 (Leuconostoc carnosum) strain cultures, most types of lactic acid microorganisms belong to the microflora that cause spoilage of meat (EFSA Panel on Biological Hazards (BIO-HAZ) (2023).…”

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