Decrease of Salmonella and Escherichia coli O157:H7 counts during dry-aging of beef but potential growth of Listeria monocytogenes under certain dry-aging conditions

Food Microbiol. 2022 Jun:104:104000. doi: 10.1016/j.fm.2022.104000. Epub 2022 Jan 31.

Abstract

Dry-aging of beef comprises the storage of carcasses and (sub)primal cuts at a low temperature and relative humidity for a prolonged period, aiming to increase the sensory quality of meat. Limited data are available on the survival and potential growth of pathogens on the surface of beef during dry-aging. Therefore, this study evaluates the changes in Salmonella, Shiga toxin-producing Escherichia coli O157:H7 and Listeria monocytogenes counts during dry-aging. A mixture of pathogenic strains was inoculated on the surface of beef loins, which were stored under four different process conditions (2 °C and 6 °C × relative humidity 75 and 85% during 42 days). Salmonella and E. coli O157:H7 counts significantly decreased during dry-aging. The daily reductions varied from -0.07 to -0.14 log10 CFU and from -0.09 to -0.14 log10 CFU, respectively, depending on the loin, matrix and condition. The reduction of L. monocytogenes was slower, with a maximum of -0.07 log10 CFU/day. L. monocytogenes counts increased with 1.0 log10 CFU on the lean meat of one loin with pH > 6.0 at the end of dry-aging, indicating that this pathogen can potentially grow under certain dry-aging conditions.

Keywords: Dry aging; Food safety; Listeria; Meat; Process hygiene; STEC; Salmonella.

MeSH terms

  • Animals
  • Cattle
  • Colony Count, Microbial
  • Escherichia coli O157*
  • Food Microbiology
  • Listeria monocytogenes*
  • Salmonella