Vacuum removes oxygen and slows mould and oxygen-driven spoilage, but it also leaves uncontested ground for microbes that can grow without air. According to the UK Food Standards Agency (FSA) guidance, non-proteolytic Clostridium botulinum can grow and produce toxin at 3 °C and above, and Listeria monocytogenes can multiply at chill temperatures in vacuum and modified-atmosphere packs.
Without other controlling factors, vacuum and modified-atmosphere chilled foods are recommended at most 10 days of shelf life at 3-8 °C, counted from the moment the product reaches 3 °C. Fresh beef, lamb and pork fall outside this guidance.
A vacuum pack works only as long as its seal does. A puncture or an opened seal in transit turns the product into ordinary packaged goods, while the date on the label still assumes vacuum.
At delivery, record together:
- Lot, time, measurement point and method
- Device ID and the temperature read
- Seal, puncture, swelling or leak observation
For a leak, a missing record or a temperature deviation, the product is set aside and an authorised person decides acceptance, rework or disposal under the product procedure. Appearance and smell do not replace that decision.