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Knowledge Base » Food Hygiene » What is Cross-Contact?

What is Cross-Contact?

Last updated on 24th April 2023

Approximately 2 million people in the UK currently have a food allergy. Food allergies are more common in children, with up to 8% of children currently having a diagnosed food allergy, compared to 2% of adults.

The severity of allergies in the UK is also increasing. The Anaphylaxis Campaign reported that hospital admissions for severe allergic reactions and anaphylaxis are increasing every year. In fact, hospital admissions as a result of food allergies have increased by 500% since 1990.

Cross-contact is a common way that people are unintentionally exposed to a food allergy and can result in even the most allergy conscious people being exposed to allergens.

What is cross-contact?

Cross-contact is when one food comes into contact with another food and an allergen protein is transferred between the foods. The contact between the foods results in the proteins mixing. Each of the foods will then contain a small amount of the other food.

Allergen proteins are extremely small and are often invisible to the human eye. This means that when proteins are transferred between foods, they may not be visible, and you may be unaware that any cross-contact has occurred.

The protein transferred between foods could be a food allergen or gluten. Even if the amount of protein that has been transferred is minimal, this could still be dangerous to those with allergies. This is because even microscopic traces of an allergen can trigger an allergic reaction.

Cross-contact could occur at any stage of the food preparation process. Even after the food has been cooked, and safe cooking temperatures that kill bacteria have been reached, the allergen proteins that have been transferred still remain hazardous and could negatively affect a person’s health and safety.

If cross-contact occurs, food that is considered to be safe may become contaminated with the allergen protein and individuals could be at risk of having a reaction. The transference of allergen proteins could be hazardous to a person’s health and safety and could result in a severe allergic reaction, anaphylaxis or even death.

Any individuals involved in any part of the food process should be aware of how to reduce or eliminate the risk of cross-contact and what actions to take if cross-contact occurs.

Food being prepared without cross-contact

What is the difference between cross-contact and cross-contamination?

Cross-contact and cross-contamination are two terms that are often used interchangeably. As cross-contact is fairly new terminology, many people, including those in the food industry, often confuse the two terms.

It is crucial that any person involved in any part of the food process and those with food allergies are aware of the difference between cross-contact and cross-contamination.

Let’s take a look at cross-contact and cross-contamination in more detail:

  • Cross-contact: This refers to direct or indirect contact between different foods that results in the allergen protein from one food transferring to another food. Once the allergen has been transferred to the food, the food should now be considered as hazardous and unsafe to eat. Cooking food that has had contact with the allergen-containing food does not remove or reduce the risk to the consumer.
  • Cross-contamination: This is when a contaminant such as a biological, chemical or physical contaminant is unintentionally transferred to food, making it unsafe to eat. Cross-contamination differs from cross-contact as the hazard can make the food unsafe for everyone to eat, not merely those with food allergies. Contaminants could include bacteria, mould, microorganisms, cleaning chemicals and viruses. Cross-contamination can result in food poisoning or another foodborne illness. When cross-contamination occurs, there is a possibility that the risk to the consumer can be removed or reduced when the food is cooked.

The main difference between cross-contact and cross-contamination is that cross-contact refers to allergens and can result in an allergic reaction, whereas cross-contamination refers to contamination that can result in food poisoning and foodborne illnesses.

Once cross-contact has taken place the allergen cannot be removed, regardless of how long the food is cooked for, whereas some bacteria or microorganisms that are transferred through cross-contamination can be killed through cooking.

If you are exposed to a hazard as a result of cross-contamination, the side effects can range from mild to severe. Many hazards result in foodborne illnesses or food poisoning.

 Some symptoms of cross-contamination include:

  • Stomach pain, cramps and nausea.
  • Vomiting and diarrhoea.
  • Loss of appetite.
  • A high temperature or fever.
  • Signs of dehydration.

For more information on cross-contamination and how to avoid cross-contamination and remove or reduce potential hazards, consult the Food Standards Agency (FSA).

If you are exposed to an allergen as a result of cross-contact, you could experience symptoms that range from mild to serious, depending on the severity of the allergic reaction. Symptoms can range from itching, hives and sneezing to hypotension, breathing difficulties and collapsing.

How does cross-contact happen?

For individuals managing food allergies, or those involved in any stage of the food process, knowing how cross-contact can happen is key to preventing future contact and reducing the risk.

Cross-contact can occur in a number of ways during the food preparation, storage or cooking process. It can be direct, meaning that the food comes into direct contact with another food that contains the allergen, or indirect, whereby the allergen transfers to the food via another source, such as through equipment, utensils, surfaces or the environment.

Let’s take a look at direct and indirect cross-contact in more detail.

Direct contact: Food–food contact

This is a common way that cross-contact occurs. Two foods or food ingredients come into direct contact, usually during the food preparation or food storage process. Quite often, the allergen was directly applied to the food and then removed. Food to food contact can also occur if different foods are stored in the same container, an allergen is removed from an already prepared food or food that is not separated properly at a buffet.

Indirect contact: Food–object contact

The food can become contaminated by an object, such as utensils, cookware, crockery or food equipment. This can happen if the same utensil is used for different foods, for example, using the same knife to cut regular bread and gluten-free bread. Not properly cleaning equipment, such as pots, pans and chopping boards can also result in an allergen coming into contact with other foods.

Indirect contact: Food–surfaces contact

Food can come into contact with allergens that are found on surfaces. If an allergen-containing food is prepared on a surface and the surface is not properly cleaned, this allergen can then contaminate a different food that is prepared on the surface. All surfaces in a kitchen, including those that do not have direct contact with food, should be properly cleaned and disinfected. This is because environmental exposure can occur, whereby the allergen is inhaled.

Indirect contact: Food–saliva/skin contact

This type of indirect contact may affect those with severe food allergies. If one person consumes an allergen and then comes into contact with another person who has a food allergy, this can result in an allergic reaction. Examples include, a baby drinking its mother’s breast milk, a dog licking your skin, and kissing or touching another person shortly after touching or eating food containing the allergen.

Dogs can be a form of cross-contact

Examples of cross-contact

Cross-contact can occur at any stage of the food process.

Some common examples of when cross-contact can occur include:

  • Salad stations – A salad station will likely have different types of salad, vegetables, dressings and toppings. They are a potential source of cross-contact because the same utensils may be used to serve different types of salad and the foods may get mixed together or fall into the wrong containers, resulting in direct contact between different foods.
  • Buffets – Buffets usually have many different types of foods, and although these foods will be in separate containers and dishes, cross-contact is very common. This is especially true on a serve-yourself buffet, as customers may be unaware of the importance of using separate utensils or may drop small amounts of food onto other food or surfaces. Some buffets may also not properly label their food so customers may not be aware when allergens are present.
  • Restaurant fryers, stoves and ovens – Even if restaurants advertise their food as being gluten-free or free from a specific allergen, cross-contact may occur if they are cooked in the same fryer, stove or oven as non-allergy or gluten-free foods. For example, gluten-free pizzas that are cooked in the same pizza oven as other pizzas can come into contact with the allergen in the oven. Restaurants should use dedicated cooking equipment for allergen-free foods.
  • Incorrect handwashing – Preparing allergens or foods that contain an allergen and then not following proper handwashing procedures can result in cross-contact. The allergen can transfer onto other food or surfaces from your hands and contaminate other food.
  • Equipment and utensils – All equipment and utensils should be thoroughly washed after each use. It is also important to use different utensils to handle different types of foods. For example, using different knives for chopping different types of food and using different cooking tongs for handling different foods. If equipment and utensils are shared between foods or not cleaned properly, allergens from one food can come into contact with another food.
  • Storing foods together – When storing food in the refrigerator, the freezer or on shelves, it is important to use different containers for different foods. Some common mistakes that result in cross-contact are storing gluten-free and regular pasta together, storing loose fruits and vegetables together, storing dairy-free products in containers that previously held dairy, and storing different types of fish and meat together.

Signs and symptoms of cross-contact

If you have an allergy and the food you have eaten has encountered cross-contact with an allergen, there are a range of signs and symptoms to be aware of. These symptoms can range from mild to severe and could even be potentially life-threatening depending on the severity of your food allergy.

Signs and symptoms of being exposed to a food allergen may include:

  • Feeling lightheaded or faint.
  • Stomach pain, nausea, vomiting or diarrhoea.
  • Wheezing or tightness of the chest.
  • A fast heartbeat.
  • Confusion and anxiety.
  • Skin reactions, such as clammy, pale or flushed skin.
  • Hives or itching.
  • Itchy, red or watering eyes.
  • An itchy, runny, or blocked nose and recurrent sneezing.
  • An itchy nose, throat, roof of the mouth or ears.
  • Frequent coughing.

More serious symptoms of being exposed to a food allergen could include:

  • A swollen tongue or throat.
  • A sudden drop in blood pressure (hypotension).
  • The narrowing of airways.
  • A weak or rapid pulse.
  • Breathing difficulties, for example, breathing that is fast or shallow.
  • Collapsing or losing consciousness.

In the case of a severe allergic reaction, the person may experience anaphylaxis and could be at risk of the reaction being life-threatening or fatal. In this situation, the individual who has experienced anaphylaxis will need immediate medical care and will likely need to be admitted to the hospital. They may also need to self-administer an adrenaline auto-injector or be given CPR.

Man suffering from being exposed to a food allergen

How to avoid cross-contact

As you cannot remove the allergens once cross-contact has taken place, preventing cross-contact from occurring in the first place is essential.

Some ways you can avoid cross-contact include:

  • Use different equipment and utensils for different foods – This includes using different chopping boards, knives, pots, pans, and stirring and cooking utensils for different types of food. Colour coding your equipment and utensils can make them easier to identify and reduce the likelihood that the wrong equipment is used.
  • Clean all equipment and utensils thoroughly – To properly remove allergen proteins from equipment and utensils, it is essential that you thoroughly clean them after every use. Using the correct cleaning products, not overloading the dishwasher, and always using hot water to clean equipment and utensils is key to ensuring allergen proteins are removed.
  • Cook allergy-safe food first – If you are cooking several foods at once, you should always prepare and cook allergy-safe food first to avoid the risk of cross-contact. You should then cover the allergy-safe food and keep it away from the other food you are preparing or cooking.
  • Use separate grills, fryers and ovens – Cooking allergen-free food and foods that contain allergens on the same surfaces can result in cross-contact, especially if they are not cleaned thoroughly between uses. Cross-contact may be even more likely in restaurants or cafes where a lot of food is cooked at one time.
  • Clean surfaces regularly – You should clean surfaces every time they come into contact with food. You should also have a cleaning schedule in place to clean other surfaces in your kitchen, such as walls, ceilings and floors, to remove airborne allergens and allergens that may have splashed or dripped onto surfaces.
  • Wash cloths, sponges, scourers and tea towels regularly – You should wash cleaning materials in the washing machine after they have encountered allergens. You should also consider replacing materials after they become worn or difficult to clean.
  • Ensure allergen-free and other foods are stored separately – You should use separate storage containers that close securely to reduce the risk of cross-contact. Labelling storage containers clearly can also help to prevent cross-contact, especially with foods that look very similar such as gluten-free pasta and regular pasta.
  • Do not share food, drinks and utensils – If you have any type of food allergy, you should never share food, drinks, utensils or crockery to reduce the risk of cross-contact.
  • Do not remove an allergen from an already prepared food – Examples include removing cheese from a burger, removing prawns from a salad, and removing nuts from a sauce. Removing the allergen from the meal will not prevent cross-contact as the allergen has already had direct contact with the food and can still cause an allergic reaction.
  • Label food correctly – All food should be clearly labelled if it contains any allergens, particularly if it contains one of the 14 allergens – celery, cereals containing gluten, crustaceans, eggs, fish, lupin, milk, molluscs, mustard, peanuts, sesame, soybeans, sulphur dioxide and sulphites. Food should also be labelled if there is a risk that cross-contact can or has occurred.
  • Ensure tables are thoroughly cleaned between diners – If you work at a restaurant, café or another food establishment, it is essential that tables are cleaned with the appropriate cleaning products and materials to ensure any allergens are removed before the next customer sits down.
  • Throw away any food that has had contact with an allergen – Even if you are not 100% sure that cross-contact has occurred, you should not risk a person with a food allergy coming into contact with the allergen. Remember that even a minimal amount of cross-contact can make the food unsafe to eat.
CPR being performed after allergic reaction

Can cross-contact be life-threatening?

In some individuals, especially those with severe allergies, cross-contact can be life-threatening, regardless of how much of the allergen the individual is exposed to. People with severe allergies can experience a serious and potentially life-threatening reaction, even if they are only exposed to a very small amount of the allergen.

In the event of a serious reaction, the individual could experience anaphylaxis. Anaphylaxis is a severe and potentially life-threatening allergic reaction that occurs when the immune system releases a flood of chemicals that can cause the person experiencing the reaction to go into shock.

Anaphylaxis can result in serious signs and symptoms, such as a sudden drop in blood pressure, breathing difficulties, narrowing of the airways, a weak or rapid pulse, and a loss of consciousness. In some circumstances, anaphylaxis can be fatal.

If there is a possibility that someone with a food allergy has eaten food that has been subjected to cross-contact and could therefore have been exposed to an allergen, any potential symptoms of a severe allergic reaction or anaphylaxis should be treated this way, even if you are not 100% sure that cross-contact has taken place.

To treat life-threatening symptoms and try and reduce the likelihood of the reaction becoming fatal, there are several ways you can treat the symptoms.

  • Use an adrenaline auto-injector – The individual having the reaction can administer the auto-injector themselves or someone else can administer it for them. If you are unsure of how to do this, consult the instructions on the side of the injector. If symptoms do not improve after five minutes, another auto-injector should be administered if possible.
  • Call 999 and request an ambulance – Ensure you tell the operator that you think the person is experiencing anaphylaxis or a severe allergic reaction.
  • Place the person in the correct position – Lie the person down and raise their legs to help blood flow to the vital organs and prevent a sudden drop in blood pressure. However, if a person is having difficulty breathing, they may need to sit up to help them breathe. If the individual is pregnant, you should lie them down on their side. If you think you are experiencing anaphylaxis, you should avoid any sudden changes to your upright posture as this could result in a dangerous fall in your blood pressure. This means that standing or sitting up should be avoided as much as possible during an anaphylactic reaction.
  • Put the person in the recovery position if they are unconscious – This can help to keep their airways clear and open.
  • Administer CPR – If the person has stopped breathing or their heart has stopped, you will need to administer cardiopulmonary resuscitation (CPR). If you are not trained on how to do this, the 999 call operator can instruct you.

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About the author

Nicole Murphy

Nicole Murphy

Nicole graduated with a First-Class Honours degree in Psychology in 2013. She works as a writer and editor and tries to combine all her passions - writing, education, and psychology. Outside of work, Nicole loves to travel, go to the beach, and drink a lot of coffee! She is currently training to climb Machu Picchu in Peru.

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