What are the 3 ways in which cross contamination occurs?

Preventing cross-contamination is one step to help eliminate food- borne illness. Cross-contamination of food is a common factor in the cause of Causes & Symptoms of Foodborne Illness. Foods can become contaminated by microorganisms (bacteria and viruses) from many different sources during the food preparation and storage process.

Table of Contents Show

Understanding Cross-Contamination
Food to Food
People to Food
Equipment to Food
Preventing Cross-Contamination
Preparing food hygienically
Storing food effectively

Understanding Cross-Contamination

Cross-contamination is the contamination of a food product from another source. There are three main ways cross-contamination can occur:

Food to food
People to food
Equipment to food

Food to Food

Food can become contaminated by bacteria from other foods. This type of cross-contamination is especially dangerous if raw foods come into contact with cooked foods. Here are some examples of food-to-food cross-contamination:

In a refrigerator, meat drippings from raw meat stored on a top shelf might drip onto cooked vegetables placed on lower shelf.
Raw chicken placed on a grill touching a steak that is being cooked.

People to Food

People can also be a source of cross-contamination to foods. Some examples are:

Handling foods after using the toilet without first properly washing hands.
Touching raw meats and then preparing vegetables without washing hands between tasks.
Using an apron to wipe hands between handling different foods, or wiping a counter with a towel and then using it to dry hands.

Equipment to Food

Contamination can also be passed from kitchen equipment and utensils to food. This type of contamination occurs because the equipment or utensils were not properly cleaned and sanitized between each use. Some examples are:

Using unclean equipment, such as slicers, can openers, and utensils, to prepare food.
Using a cutting board and the same knife when cutting different types of foods, such as cutting raw chicken followed by salad preparation.
Storing a cooked product, such as a sauce, in an unsanitized container that previously stored raw meat.

Preventing Cross-Contamination

Follow these steps to prevent cross-contamination and reduce hazards to food:

Wash your hands thoroughly between handling different foods or after using the toilet.
Wash and sanitize all equipment and utensils that come in contact with food.
Avoid touching your face, skin, and hair or wiping your hands on cleaning cloths.
Store foods properly by separating washed or prepared foods from unwashed or raw foods.
Try preparing each type of food at different times, and then clean and sanitize food contact surfaces between each task.

How to avoid cross-contamination by following simple practices in the preparation and handling of food products.

Last updated: 18 December 2017

Bacterial cross-contamination is most likely to happen when raw food touches or drips onto ready-to-eat food, utensils or surfaces.

You can avoid it by:

Preparing food hygienically

use different utensils, plates and chopping boards for raw and cooked food
wash utensils, plates and chopping boards for raw and cooked food thoroughly between tasks
make sure you do not wash raw meat
wash your hands after touching raw food and before you handle ready-to-eat food

Storing food effectively

cover raw food, including meat, and keeping it separate from ready-to-eat food
use any dish that has a lip to prevent spillages
store covered raw meat, poultry, fish and shellfish on the bottom shelf of your fridge
use different utensils, plates and chopping boards for raw and cooked food

make sure you take enough shopping bags to pack raw and ready-to-eat food separately
take extra bags to pack cleaning products and other household items separately from food
label or colour code your bags to show what you intend to use them for
check your bags for spillages after every use. If there has been visible spillage, soiling or damage, plastic bags for life should ideally be used for another purpose (where no safety risk will occur) or replaced
consider using cotton/fabric bags for life as they can be put in the washing machine and cleaned
replace old plastic bags
keep raw and ready to eat foods separate in your shopping trolley or basket

Cross-contamination is what happens when bacteria or other microorganisms are unintentionally transferred from one object to another. The most common example is the transfer of bacteria between raw and cooked food.

This is thought to be the cause of most foodborne infections. For example, when you’re preparing raw chicken, bacteria can spread to your chopping board, knife and hands and could cause food poisoning.

Cross-contamination can also happen when bacteria is transferred in ways that are harder to see. For example, via reusable shopping bags, or in the drips and splashes produced when meat is washed which can contaminate other surfaces.

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Cross Contamination

Introduction

Your cutting board may be contaminating your veggies. How is that possible? Through cross-contamination! Cross-contamination occurs when microorganisms (bacteria, parasites, viruses)are transferred from a food where they occur naturally to one where they do not naturally occur. This is dangerous because unsuspected foods are not necessarily prepared in a manner to prevent the survival of microorganisms from other sources. Taking precautions to prevent cross- contamination will minimize the risk of foodborne illness in your facility and help ensure the food your customers receive is safe.Food can become contaminated by microorganisms from many different sources during storage, preparation, and service. There are three (3) main routes through which cross-contamination can occur:

Food to food

Equipment to food

People to food

Food to food

Food can become contaminated by microorganisms directly from other foods. This type of cross-contamination is especially dangerous if raw foods come into contact with cooked or ready-to-eat foods. Here are some examples of food to food cross-contamination:

In a refrigerator, meat drippings from raw meat stored on a top shelf might drip onto cooked vegetables placed on a lower shelf.

Raw chicken placed on a grill touching a steak that is being cooked.

People to food

People can also be a source of cross- contamination to foods. Some examples are:

Touching raw meats then handling vegetables or other ready-to-eat foods without washing hands between tasks.
Using a food soiled apron or towel to wipe your hands between handling different foods.
Failing to change gloves between handling different foods.

Equipment to Food

Contamination can also be passed from kitchen equipment and utensils to food. This type of contamination occurs because the equipment or utensils were not properly washed and sanitized between each use. Some examples are:

Using unclean equipment such as slicers, can openers and utensils to prepare food.
Using the same cutting boards, utensils, and/or work surfaces for both cooked and raw foods, such as with raw chicken then with vegetables.
Storing a cooked product, such as a sauce, in an unclean container that previously stored raw meat.

Preventing cross-contamination

Follow these steps to prevent cross- contamination and reduce hazards to food:

Wash your hands after touching raw foods or items that contacted raw foods.
Wash and sanitize all food contact surfaces:
- Between use with different species of meat (beef to fish)
- When switching from raw to ready-to-eat foods.
- Every 4 hours during continuous use.
- After final use of the day.
When storing raw meats top-to-bottom always store the foods requiring higher cooking temperatures below other product (i.e., raw poultry below raw beef). See Guidelines for Final Cooking Temperatures.
Store foods properly by keeping all foods covered and separating ready-to-eat foods from unwashed or raw foods.
Prepare only one type of food at a time then wash and sanitize food contact surfaces before using them with a different food.
Plan the order of raw food preparation such that foods requiring lower cooking temperatures are prepared first (i.e., cut vegetables, then beef, followed by chicken).
Designate certain equipment for use with specific types of food only, such as using one slicer for cheeses and the other for meats.