EFSA assesses pathogen growth risks in meat intended for freezing

The European Food Safety Authority (EFSA) has assessed pathogen growth in meat from cattle, sheep and pigs intended for freezing, warning that different storage practices can significantly increase risks from Salmonella and Listeria before products reach consumers.

Commissioned by the European Commission, the assessment examines how temperature, vacuum packaging and storage time influence bacterial growth in meat from slaughter through freezing, defrosting and onward storage.

EFSA published the assessment to support possible updates to EU legislation governing meat intended for freezing.

The researchers compared different storage and defrosting scenarios with a reference case: meat stored without vacuum packaging at 7°C for 15 days. They then used mathematical modelling and “equivalence time” to determine when meat under different conditions reaches the same microbial levels as the reference.

The assessment evaluated spoilage microorganisms and key pathogens including Salmonella, Shiga-toxin producing Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica and non-proteolytic Clostridium botulinum.

Key findings

EFSA reported that storage temperature makes a major difference:

• When meat was stored at 7°C and vacuum-packed immediately after stabilisation, equivalence time before freezing was reached in just 5–6 days, driven by Salmonella.
• At 3°C, equivalence time extended to 29–30 days, with spoilage lactic acid bacteria becoming the limiting factor.
• EFSA highlighted that hygiene standards are crucial, noting that high initial contamination levels can lead to spoilage before predicted equivalence times are reached.
• During defrosting at 4°C or 7°C, bacterial growth was “absent or limited” under the conditions assessed.
• However, EFSA warned that storage after thawing can allow further microbial increases, meaning some pre-freezing storage times may need shortening.

Next steps

The European Commission commissioned the work to address “gaps and inconsistencies” in EU microbiological safety rules for frozen meat.

Based on EFSA’s findings, changes to legislation may follow, with important implications for processors, manufacturers and cold chain operators.