Salmonella: The salmonella microbe is harbored mainly by chicken and eggs, and poultry-farming methods have resulted in more cases of salmonella in recent years. Salmonella can cause acute cases of food poisoning, which is why chicken and eggs must be cooked well right through and the pots, pans and surfaces used to prepare these foods, cleaned thoroughly. Frozen foods: Ice crystals and any distortion in their shape may indicate that frozen foods have thawed for a considerable – and dangerous – period of time. Frozen foods must always be purchased last and placed in the freezer as soon as possible. According to Tymbis, «The best way to defrost a product is to place it in the refrigerator instead of at room temperature. The danger zone for the development of microbes is from 5-65 degrees Celsius, because most microbes can survive in these temperatures.» Dairy products: It is very important to pay heed to the expiration dates inscribed on these products. A swollen carton of milk means that gases have been released by growing numbers of germs. Tinned goods: Avoid dented tins as air may leak into the product from a hole, allowing germs to enter. Eggs: Eggs must be stored inside store refrigerators. The products most vulnerable to germs are those that contain two or more ingredients, because each one requires a different method of preservation. Sandwiches should not be stored for more than a day in the refrigerator.