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Are you wondering how long is it safe to keep food hot in a thermos? Don’t worry, you are not alone.
I mean, you heat it up in the morning… and the food is cold by lunch! how does that happen!?
Each week, I receive dozens of emails from MOMables subscribers wondering the same thing.
Since the invention of a thermos, people want to know how long will the food last hot, how long should the food be heated, and of course if it’s safe to eat.
Is your child’s lunch going to make him or her sick? Probably not, so relax a little. Most common food poisonings result from eating foods that contain large numbers of harmful bacteria.
The likelihood of the lunch you pack for your child in the morning growing serious amounts of bacteria in 4-5 hours, when packed properly in a lunchbox, inside an insulated lunch bag and with an ice-pack is slim (but sure, it could happen).
Today, we are talking hot foods. Hot foods you want to pack for lunch in a thermos.
After a lot of testing in the kitchen and purchasing different thermos containers I believe I have a pretty good guide for you to follow.
How long is it safe to eat? It depends on the container and how you heat up the food.
- Bacteria grows quicker between 40-140degrees F. Perishable foods should not stay at that temperature range longer than 3 hours.
- Food packed inside any lunch container should be cooked throughly at a safe temperature (no raw eggs, avoid raw onions, undercooked meats or fish).
- Soups, pastas, and any other hot foods should be heated on a stove to a boiling point (212F, 100C) and microwaved piping hot prior to packing.
- Thermoses must be preheated prior to filling.
The problem is that most parents heat up foods as hot as they would normally serve it for dinner. Remember, you are not heating up the food to eat now, you are heating it so that it can be safely eaten 3-5hours later. When you heat food like this the lunch will be cold, regardless of the container you use.
I purchased my containers on Amazon – all listed in the MOMables store- although most are available at many stores near you.
I tested the thermos containers three times by preheating the thermoses before adding the food each time. Food was filled at 7:30am and the lid came off at noon.
Here are the 5 results.
- Thermos Brand 10oz capacity Funtainer stainless. The temperature of the soup began at 210 degrees F and after 4.5 hours it was 138. Would I recommend this container? Yes. It’s great for younger kids, easy to open and fits a good portion of food.
- Thermos Brand 10oz capacity Foogo stainless. This one is similar to the Funtainer. Temperature began at 208 degrees F and after 4.5 hours was 134. Would I recommend this container? Yes. I own one. Like the one above, it’s great for younger kids.
- Aladdin 12oz BPA-free plastic. The temperature began at 210 degrees and after 4.5 hours it was 110. Would I recommend it? yes and no. Yes, if you are an adult and have access to a microwave and can reheat the food. It’s difficult for younger kids to open since the lid is wide (my 7yo could not open it).
- Lunchbots 16oz capacity stainless container. The temperature began at 210 degrees F and after 4.5 hours it was 130. Would I recommend? Yes. I own one. It has a wider mouth so it can be difficult for the younger ones to open. It has a larger capacity so it’s perfect for bigger appetites.
- Stanley 17oz stainless. The temperature began at 210 degrees F and after 4.5 hours it was 165 degrees! It was nearly too hot to eat. Would I recommend? Yes. I bought it for this test and will be using it for my husband’s lunches since he typically leaves at 7am and doesn’t eat until 1 or 2pm sometimes. It’s a great option for older kids with bigger appetites. It wasn’t difficult to open since the mouth isn’t as wide as #3 and #4. The only con is that it is bigger and bulkier.
To prove the test, I heated up a bowl of soup to a temperature my kids would eat 150 degrees (and even this was a bit hot for my son). I filled the thermos with the hot soup and after 4.5 hours in containers 1-4 was cold (barely warm at best) and in #5, the Stanley it was warm and edible.
My advice is for you to make sure you preheat your thermos, heat up the food to a boiling point or piping hot and purchase a thermos that suits your needs.
Ask yourself: will the thermos fit in my child’s lunchbox? how much food will I filling it with? will my kindergardener be able to open it? Remember, that with any new container you purchase for your child, you must teach him/her how to use it first at home.
If you are pretty new at lunch packing, need school lunch ideas, or need a little direction to make sure your child eats a varied diet, you are not alone. You can always subscribe to our school lunch plan for $6 per month.