by Andrew Thomson on February 27, 2018
Sous vide cooking is one of many growing tends on the restaurant and café scene in Australia and New Zealand. Food produced through the sous vide method is more tender and flavoursome; it can also provide competitive advantages for a savvy restaurant or cafe operation. Sous vide cooking is also high in risk.
If you are unfamiliar with the sous vide cooking method, restaurants and cafes may package a range of foods such as raw meat and chicken products in individual, vacuum-sealed bags and then slowly cook in a water bath. It is not uncommon for soups, sauces and cooked or partially cooked food to be produced as well.
So, what are the risks?
Vacuum packaging reduces the growth of spoilage organisms and harmful food poisoning bacteria that grow well with oxygen, but not with anaerobic bacteria which can flourish in oxygen free environments, such as Clostridium botulinum. Sous vide cooking generally requires longer cooking times with a temperature from 55°c which is not sufficient to destroy harmful bacteria. Potential problems can occur if the food is stored for later eating. When the food is in cold storage, listeria monocytogenes can grow at a temperature well below 5°c degrees.
Anecdotally, I’ve been made aware of chicken products being slowly cooked at a temperature of 53°c for up to six hours (or more) using incorrect equipment for a commercial operation.
Some foods are not suitable for sous vide cooking. These include whole birds (the cavity inside the birds prevents even cooking) and minced meats. Also avoid cooking large portions of mechanically tenderised meat for extended times at low temperatures.
The way forward
- Restaurant and café managers and employees involved in sous vide cooking must have an excellent understanding of the requirements outlined in the Australia New Zealand Food Standards Code and relevant guidelines.
- Conduct a risk assessment of potential food safety hazards and provide effective controls and monitoring of these hazards. A robust food safety management system is required.
- Employees directly involved in this method of cooking will require advanced skills in cooking processes time and temperature requirements. Further, for partially cooked foods, employees must have knowledge of the length of time it may take to complete the cooking step. Diligent monitoring is required here.
Specialised commercial equipment should be used:
- water baths and tip sensitive thermometers should be maintained and calibrated as recommended by the manufacturer
- separate vacuum packing equipment must be used for raw food and cooked/ready-to-eat food to prevent cross contamination
- plastic bags should be food grade and certified as suitable for cooking at high temperatures
- a combi oven such as Rational and associated equipment.
- Discard packaged food that is slimy, contains excess liquid or bubbles. Check the use-by date before reheating and serving.
There are information guides to assist a restaurant or café wanting to use the sous vide cooking method. In Australia, the New South Wales Food Authority has produced Sous vide Food safety precautions for restaurants. However, for a more practical guide Guidelines for restaurant sous vide cooking safety in British Columbia (Canada) is excellent and has been developed by the British Columbia Centre for Disease Control Environmental Health Services and the British Columbia Sous Vide Working Group.
New Zealand Ministry for Primary Industries has produced the following reports Standardising D and Z values for cooking raw meat which provides information on time-temperature combinations and Review of Microbial Pathogen Inactivation Relevant to Sous Vide Cooking at Temperatures below 55°C
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