Technical reference
Low temperatures kill slowly, so thickness and time at temperature decide the result. The sealed bag removes oxygen, so that survive can grow during slow or long chilled storage. Australia's Code sets no sous vide figure. It asks for a process step reasonably known to be safe, and its cooling and reheating still apply. The tables are guidance or templates.
Non-proteolytic C. botulinum grows without oxygen from 3.3 °C (FDA Table A-1), and a pasteurising cook doesn't destroy its . A reduction needs 10 minutes at 90 °C (FDA Table A-4). UK advice quoted by the NSW Food Authority sets a 10-day maximum at 3 to 8 °C for vacuum-packed food with no other controlling factor, and notes no growth below 3 °C.
can grow from −0.4 °C (FDA Table A-1), and it is the target of the common pasteurising cook: at 2 minutes at 70 °C (FDA Table A-3). Storage at 5 °C or below slows it without stopping it, so time matter. Fatality in listeriosis is 20 to 30% (NSW Food Authority).
Of the that matter in meat, is the one most able to grow during a long, low cook. It can't grow at 55 °C or above, and its cells start to die there. The NSW Food Authority treats it as the target organism for long, low cooking: control it and the others are controlled with it.
Lethality depends on the food. Salmon takes longer than cod, and fat and heavy salting both protect bacteria. Extended shelf life and unusual recipes need expert thermal process development.
Parameters
| Hazards | during long, low cooking and ; non-proteolytic C. botulinum and in chilled storage; anything that survives an undercook |
|---|---|
| The law, Australia | No sous vide figure. A process step reasonably known to be safe (3.2.2 cl. 7(1)(b)(ii)), then cl. 7(3) and reheating cl. 7(4) |
| Bath minimum, guidance | Water at 55 °C or above (); poultry not below 60 °C (New Zealand template) |
| Time limit, guidance | Up to 6 h below 54.5 °C (); up to 6 h heat-up plus cook below 60 °C (FoodSmart); up to 4 h to reach bath temperature (New Zealand template) |
| Heat-up by thickness, FoodSmart Category 1 | 0.5 cm 5 min; 1 cm 19; 2 cm 50; 3 cm 90; 4 cm 150; 5 cm 210; 6 cm 285 |
| Hold, 6-log Listeria (FoodSmart, NSW) | 55 °C 200 min; 57 °C 109; 60 °C 44; 63 °C 18; 65 °C 10; 70 °C 2; 75 °C 26 s |
| Hold, New Zealand template | Meat except poultry: 55 °C 420 min; 60 °C 73; 63 °C 26; 65 °C 13. Poultry: 60 °C 56; 63 °C 21; 65 °C 11. Stored past 2 days, red meat and poultry: 60 °C 91; 63 °C 30; 65 °C 15 |
| Total time from the fridge, beef (NSW Food Authority estimate) | A 25 mm portion needs over 4 hours in total at 55 °C and under 2 hours at 60 °C; a 50 mm portion close to 6 hours at 55 °C and about 3 hours at 60 °C |
| Chilled life | 5 days at 5 °C or below (FoodSmart; cooked, not pasteurised, NSW); 10 days after 70 °C for 2 min or equivalent (NSW); 2 or 5 days by method (New Zealand template) |
| Reheating | Once only. To hold hot: rapidly to 60 °C or above (Australian law). New Zealand template: above 55 °C red meat, above 60 °C poultry, for immediate service only |
| Probe | . ±1 °C (FoodSmart); tip-sensitive to 0.1 °C (NSW) |
Records that prove it
- Method for each item: category, thickest portion, temperature, times, cooling, shelf life
- Each batch: date, item, thickness, water temperature, heat-up and hold times, core readings
- Cooling time to 5 °C
- Label: food, date and time made, method, throw-out date
- Water bath and probe calibration
- Corrective action and discards, with quantity
- Validation trials, and any change to the method
Reference temperatures
Values from , a code for mass catering. Your own law or plan may set different ones.
CCP or prerequisite?
That depends on the for your process. The number, if it has one, belongs to your plan.