It is commonplace to hear on the news or social media about an outbreak of food poisoning which can be traced back to a hapless food service operation. Food safety and proper cleaning practices are serious issues that all food operators need to address. Bain marie temperature is one of the main hazards. So how long can you keep food in a bain marie?
Temperature Management
Of the 5 most common causes of foodborne illnesses, hot holding at improper temperatures comes in at number three. When food is left for too long at low bain marie temperatures which are favourable for the growth of food-borne microorganisms there is a risk of serving foods that could make people ill. Most organisms grow well between +5 ºC and +57 ºC and this is generally referred to as the food temperature safety zone. What also helps the microorganisms grow are 3 distinct factors:
- Time: Microorganisms need time to grow and multiply to critical levels
- Oxygen: Some need it but some do not require oxygen to grow
- Moisture: Most microorganisms require water to grow
The Importance Of Moisture & Heat
With the exception of botulism, bacteria cannot live without air. They need moisture and heat. The ideal growing temperature is +38 ºC. To try and control bacteria, a school Cook Supervisor will of course find it difficult to eliminate food, air and moisture but, they will have some control over time and temperature. When operating a commercial bain marie consider this:
- at +38 ºC the bacteria count can double every 15 minutes
- at 10 ºC the bacteria count will double every 15 hours
- at +2 ºC bacteria double every 15 days
- at -18 ºC most bacteria are considered dormant
How To Ensure The Right Temperature For Least Bacteria
Now that we have assessed the hazard and know the critical control points, we can set up control procedures and standards for those control points. A commercial Bain Marie is used in most schools to hold food ahead of and during service. This will either be as part of a static servery counter, or as part of a mobile bain marie hot cupboard being wheeled into the actual dining room. Due to health and safety reasons, more often than not in a school, this will be a dry well bain marie, even though some schools still use wet wells.
Either way, the bain marie temperature is set by simmerstat and goes up to +85 ºC. Ideally, you want to set it around +70 ºC so that the food is held above +60 ºC to make sure it stays outside of the temperature safety zone (+5 ºC to +57 ºC).
It is essential that the Cook Supervisor or one of the cooks probes the food when it comes out of the oven as well as before and during service depending on how long lunch is, to make sure the correct temperature is maintained.
It is also essential that when the gastronorm container is put into the Bain Marie a lid should be placed over the top until service begins. This holds the temperature of the food and stops it from drying out.
What If The Food Is On Display?
Displayed food should be stirred frequently to ensure even heating. If a wet dish is left unstirred it can form a skin on top. This is more likely to appear if there are heat lamps over the commercial Bain Marie. Again, if there is a gap in service, cover the gastronorm container with a lid to retain moisture and prevent contamination. It is also important not to mix fresh food with food that has been sitting in the bain marie for a long time. If necessary, use smaller-sized gastronorms and rotate frequently when a gastronorm container is empt.
What About High-Risk Foods?
Some food items have a long history of causing food-borne illnesses and some are prone to contamination because of the way they are typically processed and handled or mishandled during distribution. Meat items including pork, beef, lamb and poultry (chicken and turkey) are very susceptible to contamination. Cooked rice and beans and meat alternatives like soy protein are also known for harbouring bacteria and viruses. But, again: as long as these food items are held within critical control points and the food is probed regularly (if sat in the bain marie for an extended period) then the cook is mitigating against potential problems.
So How Long Can You Keep Food In A Bain Marie?
In a school setting, food is unlikely to sit in the Bain Marie for more than a couple of hours, allowing for loading before service and the lunch period. In theory, if the food temperature is kept above +60 ºC that food can be kept in the bain marie for up to 4 hours without danger. Do bear in mind though that after this long the food will have changed consistency & colour and will no longer be appealing to the students.
Peace Of Mind
So let’s say that as long as food safety measures are followed and you have a good bain marie that is able to hold food at above +60 ºC then potential hazards are mitigated. We at Kitchen Solutions manufacture commercial bain maries and bain marie hot cupboards, counters both static and mobile so please contact us with your exact requirements.
Image Source: Canva
