Useful as fridges are, they can be germ traps for the same reason as kitchen cupboards – that's where the food is kept.
Most fridges are kept at a constant temperature of about four degrees Celsius; cold enough so food is not likely to spoil
within a day or two.
But refrigerators cannot keep food fresh forever. Most foodstuffs should be thrown out after two or three days. Food spillage
inside fridges, especially meat and dairy products, can provide a festive feeding ground for bacterial colonies. Different types
of bacteria multiply at different temperatures. Although the fridge slows down bacterial growth, bacteria like salmonella and
listeria can still thrive in the refrigerator.