What is cross-contamination? (And ways to avoid it)

By Indeed Editorial Team

Published 9 May 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

When handling food or products that are for human consumption, it's important to be wary of the risk of food contamination. Taking the right steps to avoid this type of contamination is vital for the health and wellbeing of staff and customers. Companies often implement various rules and guidelines to ensure that the risk of contaminating food is as low as possible, but learning about the best practices can help you make better decisions when handling food in the service industry. In this article, we discuss what cross-contamination is, the people responsible for preventing it and the best practices for avoiding it.

What is cross-contamination?

Cross-contamination occurs when raw food or food that isn't properly cooked touches other portions of food. This can happen in several ways, such as by direct contact with food or if the individual preparing the food doesn't wash their hands, after they've touched raw meat, before touching another piece of food. It can also occur when food touches a surface, such as a cutting board, that isn't thoroughly cleaned after it has had raw food on it.

This health concern can happen quite easily because bacteria, which are invisible to the naked eye, inhabit the surface of raw food. Common bacteria, such as E. coli, are present on raw food items, such as meat, and contamination causes these bacteria to jump onto other food items, which can result in food poisoning. It also increases the risk of diseases, such as salmonella or listeria.

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The different types of food contamination

Below is a breakdown of the four different types of food contamination:

Chemical

This type of contamination happens when food comes into contact with a chemical substance. Chemical contamination often occurs in kitchens because cleaning agents are usually stored there for disinfecting counters and utensils. This type of contamination can happen during food preparation if a surface still has chemical residue on it. It can also happen before the food reaches the kitchen if a farmer uses any pesticides or fertilisers near where the food was growing.

Microbial

Microbial contamination occurs when microorganisms, such as bacteria or mould, come into contact with food. It's the most common type of food contamination and is a leading cause of food poisoning. Undercooked meat and poor food storage are the two main causes for this type of contamination to occur.

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Physical

Physical contamination arises when food items have a foreign object in them. This can happen during the food's preparation stage or during its delivery. This type of contamination carries several potential risks, such as choking or damaged teeth. Common physical contaminants include earrings, hair, cloth and stones. Certain physical contaminants might even contain bacteria, which increases the risk of contamination.

Allergenic

Allergenic contamination happens when food items that cause allergic reactions come into contact with other food items. This can happen if the same utensils used to prepare a food item that contains allergens aren't cleaned before they're used on a food item that doesn't contain the allergen. There are several well-known allergens to look out for including gluten, eggs, crustaceans and peanuts. Food allergies can cause serious allergic reactions in individuals, so it's vital to mitigate the risk of contamination.

Who prevents food contamination from occurring?

The risk of food contamination is most prevalent in the foodservice and retail industries and individuals that work in these sectors are mainly responsible for preventing it. To give you a better idea of who these people are, below is a breakdown of the professions involved in the prevention of food contamination:

Waiters

Waiters work in restaurants and their work focuses on serving customers food items. Their role in the prevention of food contamination is to ensure they don't contaminate any of the food they serve to customers. Although they aren't involved in cooking the food, they do handle the plates and utensils, which could lead to an issue with food contamination. To prevent this, waiters ensure that they've washed their hands, utensils and any work surfaces if they handle raw meat. In some cases, waiters also check the temperature of the meat to ensure it isn't undercooked.

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Chefs

Chefs work in restaurant kitchens to prepare meals for customers, which requires them to be mindful of the risk of food contamination. They regularly handle raw food and the risk of contaminating other food items is high in this profession. To mitigate this risk, chefs often wash their hands or wear gloves when preparing raw meat.

Other restaurant employees

Due to their line of work, other restaurant employees also take several steps to prevent food contamination, particularly if they've handled any raw food. This includes regularly washing their hands and not touching any uncooked or undercooked meat items. Although they don't cook the food in most instances, all staff in a restaurant have the potential to cause food contamination due to their proximity to the food.

Personal shoppers

A personal shopper purchases food on behalf of a client, so there's a potential for food contamination in their line of work. To prevent this, personal shoppers often separate raw meat items by placing them in their own bags. They might also check expiration dates on items or wash their hands after handling food packages that contain raw meat.

Supermarket employees

Individuals that work in a supermarket often handle raw food when stocking shelves in the store, which can potentially lead to food contamination. These employees can reduce this risk by using protective gloves while stocking shelves. They may also wash their hands after touching any raw food products to help lessen this risk.

Food manufacturers

Food manufacturers have a similar risk to chefs when it comes to food contamination because they directly handle raw food and the equipment that's used to prepare raw food. These employees can mitigate this risk by using gloves to handle raw food and sanitising workstations regularly. Companies usually implement a specific policy if they're manufacturing food to prevent contamination.

Food delivery staff

Restaurants that offer delivery services require food delivery staff to drop the food off to customers. For these individuals, there's a risk of food contamination when they deliver the food. To mitigate this risk, food delivery staff often wash their hands after a successful delivery or if they've handled any raw food in transit. They may also do their best to avoid touching any uncooked meat.

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Best practices to prevent food contamination

To ensure that the risk of food contamination is low, there are several best practices that you can follow. These include:

When out shopping

When you're at a supermarket purchasing food, it's a good idea to keep your hands clean by using a hand sanitiser. For optimal results, do this every time you touch raw meat and make sure your hands are clean before touching other types of food. If you can, use gloves or tissues to avoid touching any raw meat with your bare hands. Another important guideline to follow is to check the best before date on food before you buy it. You may also look at the meat itself to see if there's any discolouration or other signs of spoilage.

When storing food

When storing raw meat, it's important that you package it appropriately to avoid any contamination with other food. For instance, if you're using a fridge to store raw meat, use a separate container so other food items don't come into contact with it. If you handle any raw meat, be sure to wash your hands before and after. In addition, try to clean the fridge regularly with a disinfectant to ensure that there's no buildup of bacteria.

When cooking food

When preparing food, use a cutting board that's specifically for raw meat to avoid contaminating other food items. You can also purchase a meat sanitiser and apply it to the surface of cutting boards to minimise the risk of contamination before cutting meat. Make sure that you clean the cutting board thoroughly after use with hot, soapy water or a sanitiser solution.

When eating food

Make sure that you've washed your hands before handling any food. Use a disinfectant soap if you've touched any raw meat and intend to handle any cooked meat before you eat. If there's a plate used for raw food preparation, avoid putting any cooked food on the same plate. Instead, try to keep all cooked and raw foods separate, even when in the fridge. To mitigate the risk of spoiled food, try to avoid food from buffets or restaurants that leave food out in the open for a prolonged period.

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When serving food

Always wash your hands thoroughly if you've touched raw food and try to avoid touching any cooked food until your hands are clean. Once you've cleaned your hands, it's important to dry your hands completely before serving any food. Otherwise, bacteria from your wet hands could contaminate the food.

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