Meat aging is a process during which microbes and enzymes break down the connective tissues in meat, resulting in a tenderized and flavorful final product. Wet-aging is used for beef, pork, and lamb that is stored and refrigerated in a vacuum package. Dry-aging is reserved for beef and involves refrigerating meat without packaging, causing a dry surface to form on the beef that is later removed from the final product.

EFSA scientists looked at the ways in which food business operators commonly dry- and wet-age meat, taking into consideration different combinations of time, temperature, relative humidity, air flow, packaging type, and other variables. EFSA also identified relevant microbiological hazards and bacteria associated with the aging of meat, including foodborne bacteria Shiga-toxin producing Escherichia coli (STEC), Salmonella, Staphylococcus aureus, Listeria monocytogenes, Yersina, Campylobacter, and Clostridium; mycotoxin-producing fungi Aspergillus and Penicillium; and numerous bacteria responsible for the spoilage of meat.

Regarding the mold-forming, mycotoxin-producing fungi Aspergillus and Penicillium, EFSA determined that mycotoxin production may be prevented during aging by ensuring a meat surface temperature of -0.5–3.0 °C, with a relative humidity (RH) of 75–85 percent and an airflow of 0.2–0.5 meters per second (m/s), for up to 35 days.

Aging of meat is a complex process that depends on a multitude of factors, many of which change with time, resulting in inconsistent bacterial behavior across products. However, using predictive modeling, EFSA concluded that there are no additional risks involved with aged meat in comparison to fresh meat, provided that the specific combination of time and temperature outlined in the scientific opinion are observed during the aging process. In general, EFSA recommends not allowing meat surface temperature to exceed 3 °C during aging.

Finally, using a hazards analysis and critical control points (HACCP) framework, EFSA identified practices during production and storage that would further assure the microbial safety of aged meat. The opinion stresses that HACCP principles and good hygiene practices should be applied at every step of aged meat production, and exemplifies current recommendations with dry-aged beef.