Types of Cross-Contamination and How To Prevent Them

Cross-contamination is the spread of bacteria, viruses, and other harmful components from one surface to another. Types of cross-contamination include food-to-food, people-to-food, and equipment-to-food and you prevent it by following good practices when shopping, storing, cooking, and transporting food.

Cross-contamination, the transmission of bacteria, toxins, and other contaminants to foods, is one of the leading causes of food poisoning. However, it’s relatively easy to avoid, as forming a particular set of habits will help eliminate cross-contamination within your house. Here’s what you need to know.

Cross-contamination is the spread of bacteria, viruses, and other harmful components from one surface to another. Usually, this transfer happens due to not disinfecting and sterilizing surfaces and equipment. While any surface can be contaminated, the biggest worry comes from cross-contaminating foods.

To understand cross-contamination, imagine cutting raw chicken. Raw meat contains several contaminants, most of which are killed when you cook the meat. Yet, these contaminants are also on the surface of the knife — where they can stay active for a long time. If you use the same knife to cut a vegetable that won’t then be cooked, you risk eating active contaminants.

Eating these contaminants can lead to foodborne illness. Foodborne illness is caused by consuming food or water contaminated with pathogenic bacteria, viruses, or parasites. Each year, there are an estimated 48 million cases of foodborne illness in the United States. About 3,000 result in death.

Cross-contamination can be prevented by following good food safety practices. These include washing hands and surfaces often, using separate cutting boards for raw meat, vegetables, and cooked food, and cooking meat to the proper temperature. However, the greatest danger comes from cross-contamination before food reaches your hands.

Hundreds of different contaminants can be transmitted from surface to surface. From bacteria to allergens, the degree of danger they present often depends on the person eating the contaminated food and the number and type of contaminants present. 

The most common contaminants involved in cross-contamination are bacteria and viruses — which make up most cases of food poisoning. However, parasites such as protozoa and tapeworms can also be spread from surface to surface. Similarly, although less common, is the cross-contamination of toxins and molds, which contain chemical and natural toxins.

Finally, allergens can also spread through cross-contamination. For example, a peanut allergy may be triggered by other foods that were near, or in direct contact, with peanuts. Allergen-related cross-contamination isn’t a problem for everyone, but one must take extreme care if aware of any allergies.

Experts agree that there are three different types of cross-contamination in food — food-to-food, people-to-food, and equipment-to-food. While not all of these are under your control, it’s important to know how each can happen and their consequences.

Food-to-food

The most obvious type of cross-contamination involves food-to-food contact. For example, if you place a vegetable near a raw steak and they wind up touching, the vegetable can be contaminated. Similar occurrences may happen in the fridge, where a dripping piece of raw meat may leak contaminated liquid onto another food.

People-to-food

Another common form of cross-contamination involves people-to-food transmission. People can also transfer contaminants from one food to another in many ways, from using the bathroom without washing their hands to not disinfecting after manipulating raw meats. Naturally, you can avoid this in your own home — but not so much in a packing facility, grocery store, or restaurant.

Equipment-to-food

Finally, equipment-to-food cross-contamination is also possible and acts similarly to people-to-food. By not disinfecting and cleaning knives, cutting boards, and other utensils between each use, one can transfer contaminants from one food to another. 

Cross-contamination can cause a myriad of symptoms and side effects, most often including vomiting and dehydration. Due to the vast number of contaminants transmitted through cross-contamination, it’s impossible to determine specific symptoms for everyone. However, some side effects seem to be common for most people.

Foodborne illnesses usually cause:

• Vomiting
• Diarrhea
• Fever
• Abdominal pain
• Headaches 

These symptoms are treated individually by prescribing specific medications, such as antidiarrheal drugs or antispasmodics. Antibiotics may also be prescribed to attack the infection directly. However, doctors may also choose not to use drugs and wait for the body to get rid of the infection by itself. 

In cases of severe food poisoning, you may need to stay in the hospital for a set period. Serious cases of foodborne illness involve severe diarrhea and vomiting, two symptoms that can cause serious dehydration and malnourishment when combined. Staying at the hospital will allow doctors to counteract this through intravenous injections.

Preventing cross-contamination is no easy task — but by ingraining a few habits into your cooking space, you can avoid it as much as possible. For easier remembering, you can divide cross-contamination prevention into four stages: shopping, storing, cooking, and transporting.

Shopping

Preventing cross-contamination starts at the grocery store, as soon as you grab a product that could transmit contaminants. Handle raw meat, poultry, and eggs with care to avoid leakage and contact with other foods that don’t need to be cooked. Experts recommend taking the following steps:

• Place these kinds of foods in separate bags to avoid leakage
• Use separate shopping bags for possibly-contaminating foods
• Separate groceries and place them in different places, such as the trunk and the back seat of your car

Storing

Once you get home, it’s important to store things as soon as possible before relaxing. Taking too long before placing foods in the right place can cause cross-contamination and food poisoning. Furthermore, doing this early prevents losing the chill in raw meat, poultry, and similar foods.

• Keep eggs away from other foods in their original carton
• Store fruits, vegetables, and other ready-to-eat foods in separate containers
• Place meat, poultry, and seafood on the bottom of the fridge to avoid leakages

Cooking

Naturally, the cooking time is when cross-contamination is more prone to happen. Knives, hands, and counters are all perfect vehicles for contaminants, so it’s crucial to form good disinfecting and prevention habits to avoid foodborne diseases.

• Wash your hands before, during, and after handling raw meats and foods
• Separate knives, cutting boards, and other utensils depending on whether they’re used for raw or ready-to-go foods
• Periodically clean and disinfect surfaces such as dishcloths and counters

Transporting

Finally, but not less important, it’s fundamental to understand how to transport food in lunch boxes and Tupperware. Handling all of these stages correctly will effectively prevent 85% of foodborne illnesses — so make sure to form the necessary habits.

• Clean your lunch boxes and Tupperware after every use
• Use cold packs and thermal containers whenever necessary
• Don’t reuse a container that has stored contaminant foods before washing it first