Thermoses are capable of keeping drinks hot and cold drinks cool for long periods of time. They are beneficial in our lives as it helps us drink our favourite beverages like tea, coffee, water, lemonade, etc., during the hot or cold months of the year. Outside of these drinks it's also possible to put other products like milk, yoghurt, chicken soup or stew into the thermal flask. However, if these foods are not carefully prepared beforehand or these foods are not consumed within a safe appropriate time, there is a risk of food poisoning or salmonella. A thermos is a great corporate gift which creates an opportunity to connect with your clients, however, when purchasing a large order of custom made thermoses as a corporate gift for your customers; It is important to know the food safety that comes when preparing a thermos for lunch: how long is it safe to keep food hot in a thermos, should I heat the food beforehand, or can I microwave my thermos to heat up my food. These are important questions to know if you are providing information to your customers about thermos food safety as part of your corporate gift. The answers to these questions will be addressed below.
How Long Is It Safe to Keep Hot Food in a Thermos?
Bacteria can rapidly grow at temperatures from 4°C to 60°C, therefore decomposable foods in thermoses should not stay at this temperature range for more than 3 hours. To be one the safe side, one method to track the temperature of your food in the thermos is to use a thermometer and to time how long the food has been in the thermos. You can check both the time and how hot the food is before u pour it in the thermos and then check it again later before eating. If it's been below 60°C and it's been over 4 hours, it's best to discard the food. To ensure it's safe to eat food in a thermos it must be prepared correctly beforehand.
How to Prepare Hot Food
Before, putting your previous night's leftovers into your thermos or thermal flask, you have to make sure you reheat the food and its piping hot before you pour it into your thermos. Hot foods should be heated to 100°C before being added to the thermos.
How to Prepare a Thermos
Before adding hot food to a thermos, the thermos should be heated up before hand to help with retaining the heat of the food in the thermos. First, add boiling hot water from the kettle into the thermos and cover it. Wait over 5 minutes while you heat the food. Then, carefully pour out the boiling hot and add your piping hot food into the thermos and seal the lid.
How to Prepare a Thermos to Eat Cold Food
Cold food like smoothies, yoghurt or milk can be stored in thermoses. However, extra precaution needs to be taken for dairy products as there is a risk of salmonella if the foods aren't properly cool. Milk can be kept cool in a thermos for 2-6 hours as long as it stays below 4°C. Once it rises above 4°C it needs to be drank within 2 hours or else it should be thrown out. Most fridges are set at 4°C which is pretty close to the danger zone of bacteria growing once it leaves the fridge. Before putting cold foods in the fridge, you can try to put it in the freezer for a short period of time or reduce the overall temperature of your fridge beforehand. In addition, you can put your thermos in the fridge overnight and add cold ice to reduce its temperature. The next morning you can remove the ice and add the cold milk to the thermos. This method applies to all cold foods and cold drinks.
Can a Thermos Be Put in the Microwave?
The short answer: No! Regardless of what food or drink you are trying to reheat; stainless steel can NOT be put into the microwave. When metal is put into microwaves, the metal will spark and these sparks may cause a fire or an explosion. If you absolutely must reheat your food, pour the food from the thermos into a microwavable container and put it in the microwave. When sending your customers or employees a thermos as a corporate gift, please remember to specify that it is not microwavable.
FAQ
It is recommended to heat up your thermos by adding boiling hot water to rise the temperature of the thermos' surface to ensure food stays hot longer
Bacteria can quickly grow at temperatures from 4°C to 60°C, therefore perishable foods in a thermos or thermal flask should not stay at this temperature range for more than 3 hours.
No! Microwaving stainless steel is dangerous and can cause a fire or an explosion.
Graduated with a Masters degree from Ireland with a Masters degree in Business Information system. English native speaker specialising in business and data analyst. Currently enrolled in Tunghai University's language centre for studying Mandarin Chinese and undertaking a student marketing internship at SourceEC. My role involves content writing, SEO analysis and web page optimisation After my studies and completion of this internship, I am hoping to pursue a career in data analytics in the digital marketing field in Asia.
