by Dr Deborah Lee, Dr Fox Online Pharmacy
92% of UK households use a microwave for cooking. It’s quick and convenient, does not alter the nutritional quality of the food, and uses relatively little energy. A 700W microwave run for 3 minutes will cost around 1p! For the most cost-effective option choose one with an energy rating A-B. In the current cost of living crisis, cooking by microwave is a very attractive option.
Microwave cooking is endorsed by Public Health England. However, most people have little understanding of how their microwave works and how serious health problems can arise if it is not kept clean.
How does a microwave kill bacteria?
The microwave heats food to a temperature that destroys bacterial organisms. This must be to at least 149°F (65°C) (below the temperature of boiling water.) The microwave contains a magnetron which produces low energy radio waves. These bounce off the metallic inside walls of the microwave and are absorbed by the food, which heats it up. Microwaves have been found to kill bacteria even at lower temperatures by destruction of the bacterial cell wall.
It’s important to realise that improperly cooked microwaved food is a common cause of food poisoning. This is because there may be ‘cold spots’ in the foods during cooking. The microwave can only penetrate the food to a depth of 2 cm. So, the microwave cooks the food from the outside first and the middle position last. For these reasons, the food needs to be carefully heated in a microwave, stopping and stirring regularly, and not eating the food until it is piping hot all the way through. Ideally, use a thermometer. The food should reach 75°C for at least 30 seconds.
Commonly found bacteria in microwaves
E.coli and salmonella have both been found in microwaves. In fact, the microwave has been referred to as a ‘microbial hotspot.’ Raw meat is a potent source of these types of bacteria. In addition, food splatters in the microwave and can end up in the crevices and under the rotating plate. Bacteria are frequently present on the handle which is grasped over and over again.
How do you know if your microwave is a health risk due to bacteria?
You can tell your microwave is unhygienic if when you switch it on the kitchen quickly fills with a horrible, perhaps a burning, smell. When you look inside, you might see old food splattered around and even patches of mould.
How can you avoid getting bacteria in the microwave?
To keep your microwave germ-free, you must regularly clean it and do this thoroughly. One way is to put a bowl of water and vinegar in the microwave and switch it on for 2 minutes. Then remove and wipe out the inside of the microwave with a damp cloth. By the way, it’s not recommended to spray kitchen cleaner inside the microwave directly as it can get into the vents and could get mixed with your food.
What can you do if your microwave is contaminated?
Follow the above cleaning instructions. Add lemon juice to the vinegar and water cleaning solution and microwave for 2 minutes, but keep the door shut and allow the steam inside it to percolate for 15 minutes. If it’s still dirty, make a paste with baking soda and water and lather this onto the affected areas. Any very stuck-on residue can be scraped off with a plastic implement such as an old credit card.
When to replace your microwave
A microwave can last 7-8 years but some give up the ghost long before this. If your microwave has the following – it’s time for a new microwave –
- You can’t get rid of a burning smell when it’s cooking
- The food seems to be constantly undercooked
- The door doesn’t shut properly
- The keypad doesn’t work
- The wiring looks suspect
- It is very noisy when turned on
There is obvious staining, rust or peeling edges.
Is it time you gave your microwave a clean this autumn?