EFSA assesses bacterial growth in meat intended for freezing

The European Commission asked EFSA to carry out this risk assessment to address gaps and inconsistencies in some of the EU rules on the microbiological safety of meat intended to be frozen.

The study analyzed the influence of temperature, time, and packaging type on microbial growth, considering Salmonella and Listeria, and bacteria that spoil meat's smell and appearance.

Experts compared various meat storage and defrosting scenarios with a reference scenario (meat stored without vacuum packaging at 7°C for 15 days), observing differences in microbial growth. Experts applied the concept of equivalence time, using mathematical models to predict the amount of time meat can be stored before freezing under different conditions until it reaches the same microbial levels as in the reference scenario.

• When storing meat at 7°C that was vacuum-packed immediately after stabilisation, equivalence time before freezing was determined by Salmonella and was reached in 5-6 days of post-slaughter storage.
• When storing meat at 3°C, equivalence time before freezing was determined by spoilage lactic acid bacteria and was reached in 29-30 days post-slaughter. In certain situations, when initial bacterial contamination of meat is high, spoilage may happen before reaching these predicted equivalence times.
• When defrosting meat at 4°C or 7°C under the conditions assessed, bacterial growth was absent or limited.

Further storage of meat at 4°C for 7 days after defrosting may lead to additional bacterial growth depending on the storage conditions, suggesting that pre-freezing times in some of the scenarios should be shortened to reach equivalence with the reference scenario.

Based on these findings, the European Commission may propose changes to EU legislation.