What's up with cross-contamination?

Question

I admit I don't understand. Either a food is contaminated or it's not. If you allow bits of contaminated food to touch non-contaminated food, then the non-contaminated food is suddenly contaminated. So far, so good. But I'm led to believe that if two non-contaminated foods are combined, there is a greater risk that this mixture will become contaminated. Is this right?

Answer 1

Makes sense in the context of genetically-modified foods. If you take two UNmodified foods, and mix them they have a higher chance of cross-polination, I would think, and therefore of cross-contamination.

Answer 2

All food carry bacteria, different foods carry different kinds of bacteria. So if you cut say a chicken breast on a cutting board then cut tomatoes on it, the tomatoes now carry both types of bacteria.

That becomes a proplem when some items are cooked and others aren't, or aren't cooked in the same maner, where the heat doesn't get as high, thus killing those potentially harmful bacteria.

Answer 3

Well, yes, it's true. It greatly depends on the foods touching as to the time it takes for them to go 'bad'. It is beneficial for lemon juice to touch in cut fruit in small amounts as it keeps the color of the fruit from turning brown. However, Apples touching bananas (even skins on) or a citrus fruit in your pears and apples, or even onions and potatoes touching can cause them to rot quickly.

Answer 4

Cross Contamination is the physical movement or transfer of harmful bacteria from one person, object or place to another.

Cross contamination is a key factor in food borne illness (food poisoning), and it has four common sources:- food, people, equipment and work surfaces.

FOOD

Raw perishable foods can contain harmful bacteria. For example, raw meats contain a large number of naturally occurring bacteria such as Salmonella, Campylobacter and Listeria, which are all causes of food borne illness.
If you are not careful, harmful bacteria can easily be transferred from raw to cooked or ready to eat foods, examples of this are:-

Due to incorrect storage methods, raw meat may drip blood and juices onto cooked foods such as ham, and quiche, or other ready to eat foods like salads, dressings and sauces.
When raw and cooked foods are combined to make salad rolls, sandwiches and mixed salads, harmful bacteria may be transferred from salad vegetables to other foods (like meats, cheese or egg). If these products are then not kept refrigerated the bacteria can multiply and may cause food borne illness.
PEOPLE

Harmful bacteria live in and on our bodies, especially on and around our faces and hands, and on our clothing. As they are usually present in small numbers they do not make us sick. If these bacteria are transferred from our bodies or clothes onto food, and allowed to multiply, the food can become unsafe to eat.
EQUIPMENT

Bacteria are able to live and multiply in any cracks and crevices in equipment including the surface cuts of chopping boards. After equipment has been used, bits of food containing bacteria remain. If the equipment is not properly cleaned, when it is used next the bacteria will be transferred to another food.
WORKING SURFACES

Surfaces such as bench tops may have bacteria on them from contact with people, raw foods, dirty equipment or other things such as cartons that have been stored on the floor. If the bench tops are not properly cleaned, any food placed on them will be contaminated by the bacteria.

Answer 5

no it also has to do with the person handling the foods and how it is prepared