Different types of food contamination and how to avoid them in your production line
No manufacturer wants to discover that a batch of their food products is contaminated. Food that has been tainted can cause serious harm – or even death – to those who consume it.
In the summer of 2019, six people died across nine NHS trusts after eating pre-packed chicken sandwiches infected with listeria. The deadly strain was linked to meat produced by North Country Cooked Meats that were used in the sandwiches.
The company’s factory was forced to close for inspection and then went into liquidation, taking down its distributor North Country Quality Foods. The closures resulted in 46 job losses. The Good Food Chain, which had unknowingly made the sandwiches with the contaminated meat also collapsed, putting a further 125 people out of work.
When consumers are injured or die due to food contamination, the companies involved have enormous repercussions. In the worst cases, companies can go out of business, and people lose their livelihoods. Even if they get through the contamination crisis, they will likely emerge with a severely tarnished reputation and a big dent in their finances.
Food manufacturers must do everything possible to avoid contamination and produce safe products, knowing the dramatic consequences if they don’t.
There are four types of food contamination: physical, biological, chemical and allergenic. This blog explains these categories and provides tips on how to avoid them.
- Physical contamination
- Biological contamination
- Chemical contamination
- Allergenic contamination
- How to prevent contamination in your plan
Physical contamination
This category contains an almost endless list of contamination culprits. Here are just a few:
- Hair: Every food manufacturer should insist that factory floor workers wear a hairnet to minimise contaminants.
- Glass or metal: Glass and metal can make their way into your output from broken equipment, facilities and containers. Aim to report such breakages swiftly. You should stop the production line and deep-clean it until you are 100 per cent certain that every piece has been cleared. A robust Equipment Maintenance Plan can also reduce the chances of breakages that lead to contamination.
- Pests: No one wants to find animal droppings in their food. Yet pests such as mice, rats and cockroaches produce urine, saliva, fur and faeces – all of which could end up in your product if your premises are not kept clean. Even worse, these pests – plus a whole variety of insects and spiders – can make their way into food.
- Jewellery: Finding jewellery or components of broken jewellery in food is unacceptable to consumers, who will lose trust in you and quit buying your brand. Managers must therefore insist that no worker handling food is permitted to wear jewellery of any kind.
- Dirt: Detecting dirt is a challenge as the particles are often tiny. It can get into food if there are any unwashed ingredients such as fruit and vegetables. The solution is to wash all raw materials before entering the production line thoroughly.
- Fingernails: Carry out spot-checks to ensure everyone working on the production line keeps their nails short and clean to prevent contamination. Ban the use of nail varnish or fake nails – as these can easily fall off or chip and contaminate food.
Biological contamination
There are many types of biological contamination. The problem occurs when bacteria or other harmful microorganisms get into food. They are a common cause of food poisoning, spoilage and costly waste.
Biological hazards include microorganisms such as bacteria, viruses, yeasts, moulds and parasites.
Examples of biological hazards include:
- Salmonella
- E-coli
- Clostridium botulinum / Clostridium perfringrens
- Campylobacter
- Norovirus
As with the North Country Cooked Foods example above, food poisoning can be deadly and bring about a company’s demise.
Food poisoning can happen when disease-causing bacteria spread to food that is then consumed. Bacteria are microorganisms that divide and multiply exceptionally speedily. When the conditions are right, one single-cell bacteria can multiply to two million in just seven hours.
Some foods are more susceptible to biological contamination than others because they provide the perfect environment for bacteria to thrive and multiply. These foods have a high water or moisture content and neutral acidity (pH). These are high-risk foods that every manufacturer must ensure are the subject of strict safety protocols.
When high-risk foods are left in what is known as the Temperature Danger Zone – above 8°C and below 63°C – the rate of microbial growth speeds up, and the risks can be sky-high.
Chemical contamination
Familiar sources of chemical contamination in food processing include:
- Chemical cleaning agents: To avoid potentially harmful chemicals making their way into the food chain, you need to ensure machinery is thoroughly rinsed during the cleaning process and that all your equipment is well maintained. Never keep ingredients stored in the same place as your cleaning chemicals.
- Unwashed fruits and vegetables: Pesticides and fungicides on fruits and vegetables can be harmful if ingested, so it’s essential to ensure they are thoroughly washed.
- Pest control products: Chemicals used to eradicate pests are hazardous. Such products must always be stored separately from ingredients and food items. Don’t use pest control products on or near production lines.
Allergens
The UK’s Food Standards Agency (FSA) has identified 14 main allergens:
- Celery
- Cereals containing gluten, including wheat, rye, barley and oats
- Crustaceans – such as prawns, crabs and lobsters
- Eggs
- Lupin beans
- Molluscs such as mussels and oysters
- Mustard
- Tree nuts – including almonds, hazelnuts, walnuts, brazil nuts, cashews, pecans, pistachios and macadamia nuts
- Peanuts
- Sesame seeds
- Soybeans
- Sulphur dioxide and sulphites (if they are at a concentration of more than ten parts per million)
You can take several steps to minimise the transfer of allergens across the factory floor.
Firstly, you must ensure that suppliers of products containing allergenic ingredients correctly label them and store them separately. Each unit must be tightly sealed as even a tiny amount of leaked allergen can result in a costly recall or, at worst, severe illness or even the death of the consumer.
Cross-contact can also be avoided by running long production lines for products with common allergens, staggering production times and using specialist equipment.
It is also vital to train employees about the importance of avoiding cross-contamination. Then assign them to specific locations to minimise cross-contact during staff changeovers.
From purchasing ingredients to staff education and cross-contact prevention, a lot of thought and planning goes into establishing an allergen management system. Ensuring yours is effective is crucial for customer safety and industry standards.
How do I prevent contamination?
For optimal quality, you need to ward off every type of contamination. Below, we’ve listed our top tips for mitigating the threat.
Maintain high hygiene practices
Hygienic handling minimises most forms of contamination.
Examples of hygiene measures you should take include:
- Regular hand washing to prevent bacteria spread
- Cleaning machinery and other equipment between batches to stop cross-contamination, primarily if you work with multiple products that could lead to allergens
- Washing raw materials before processing, especially if sourced from external locations where they could be subject to chemical, biological or physical contamination
- Encouraging staff to wear PPE, such as gloves and hairnets, to reduce user contamination
The exact hygiene regime you implement will be tailored to your products so spend time coming up with a technique that works for your needs.
Train staff
Preventing contamination is a workforce-wide effort. You need to give your staff the knowledge and tools to handle your products properly and minimise risks.
Invest in staff training and communications that lead the way. This could include teaching them how to use PPE or explaining what they should and should not wear in the production environment. It will also involve taking them through hygiene procedures and ensuring they abide (such as regular hand washing or cleaning rotas).
Finally, make sure they know how to operate your equipment efficiently. This minimises the risk of user error causing contamination, including cross-contamination between product lines.
Invest in appropriate product inspection equipment
One of the simplest ways to avoid contamination is to inspect your products. You must find the appropriate equipment to review your output and uncover any issues.
There are a few options on the market:
- Checkweighing – allowing you to check the weight of your output. If the weight is too high, it could be a sign there are dense contaminants, such as metal or stone, in your products
- Metal detection – enabling you to uncover metal parts in your products
- X-ray – offering advanced inspection and the ability to detect a wide variety of contamination
You might combine multiple inspection forms to find the appropriate fit for your plant. X-ray typically offers the highest possible level of quality control. It can even allow you to identify other product flaws, such as cross-contamination or broken seals, that could lead to sizeable issues.
Even so, product inspection equipment will not cover all types of contamination, such as bacterial or chemical forms. You should therefore use it in conjunction with a robust cleaning regime and other safeguards.
Create a risk-free environment
The wrong conditions can lead to contamination. You need to create a risk-free environment.
For example, to prevent bacterial contamination, implement robust processing and storage strategies. Ensure you have ‘kill steps’, such as the pasteurisation of milk and juices or using vacuum sealing to hinder bacterial growth.
Similarly, create a regularly maintained and reliable production line to reduce physical contamination from broken parts.
If you work on multiple projects in the same plant, you will also need to have appropriate processes in place to avoid cross-contamination, such as spacing out lines and specifying equipment for each line rather than reusing.
Start by considering the various threats in your production, including contaminations most likely to impact your output. This will enable you to create a strategy that overcomes any obstacles.
Have an end-of-line quality control point
Despite your best efforts to avoid contamination during production, there will also be a risk something can sneak in. Addressing this before reaching your customers is crucial to preventing disaster and maintaining brand reputation.
Have an end-of-line solution that conducts a final check on your output and a last chance to find contaminants. Typically, this will come in the form of product inspection equipment but seek a method that works for you.
With this final safeguard, you can allow your products to leave the plant with the confidence that they are of the utmost quality.
Parting words
Preventing food contamination is of utmost importance, so all manufacturers should ensure their processes adhere to global food safety standards.
Doing so means you can consistently meet customer expectations and protect them while driving positive brand sentiment and reducing the risk of consequences – such as product recalls, complaints and even legal action.