Contamination of Food

The following substances can cause food contamination:

• During food production, microorganisms can survive the thermal preservation process. Contamination is also possible during processing, e.g. when animals are slaughtered and pathogenic bacteria of the intestinal tract contaminate the meat carcass. Pre-cut salads can also become contaminated during processing if the wash water is not constantly renewed.
• Food is contaminated with heavy metals and impurities from the atmosphere that find their way into water and soil. For example, rocks naturally contain heavy metals that plants can absorb through the soil.
• Food becomes contaminated with allergen residues through unintentional or accidental transfer. For example, nuts often end up in chocolate through cross-contamination when nut chocolate was previously made.
• Food can be contaminated with mycotoxins at various stages. Mycotoxins are metabolites of molds that can have a toxic effect when consumed. Primary mycotoxin contamination occurs when crops are infested with molds. Secondary contamination occurs when raw materials become moldy during storage or transport.

The Tentamus Group has a global laboratory network with a wide range of analytical methods for food safety, which include contamination analyses. These are based on the advice and regulations of food safety organizations such as the BfR (Federal Institute for Risk Assessment).

Using analytical methods and experienced staff, the Tentamus Group performs testing services for common food contaminants:

1. Process-related Contamination of Processed Foods

Determination of process-related contamination of 3-MCPD, 2-MCPD and glycidyl fatty acid esters in foods containing refined vegetable oils (by GC-MS).

• 3-MCPD are formed during the refining of edible oils and fats and are therefore mainly found in fried foods, bakery products, margarine, hazelnut spreads or infant and follow-on formula.
• 2-MCPD is a contaminant of soy sauce and acid hydrolyzed vegetable proteins. Humans are usually exposed through consumption of palm oils and fats.
• Glycidyl fatty acid esters are one of the main contaminants in processed oils. They are typically formed in the deodorizing stage of refining. These residues are therefore present in most refined edible oils.
• Other process contaminants include: Chlorate, THP, antraquinones, trimesium.

Determination of acrylamide in food (by LC-MS/MS)

• Acrylamide is commonly found in coffee, processed potato products, and grain products during the Maillard reaction or “browning” process (when a product is cooked at >120°C).
• The Maillard reaction is a chemical reaction that occurs between amino acids and reducing sugars. When heat is applied to a food containing amino acids and sugars, the heat acts as a catalyst that causes the sugars and amino acids to react, resulting in non-enzymatic browning of the food. The reaction causes acrylamide, or the “browning effect.”

2. Food Contamination with Heavy Metals & Pollutants

Heavy metals are all metals with a density greater than 5g/cm³. Common heavy metals include lead, copper, iron, zinc, tin and nickel. These pollutants are found in the air and enter the food chain through water and soil, where they are used as animal feed and as plant fertilizers.

• Not all heavy metals are harmful. For example, zinc and copper are essential for a functioning ecosystem. However, in high doses, all heavy metals are toxic to humans.
• In Regulation (EU) No. 2023/915, the EU lays down the legal maximum levels for heavy metals in foodstuffs.
• Heavy metals also pollute honey in a natural way. Heavy metal levels in honey give a general indication of the degree of environmental contamination.
• Traces of heavy metals remain in the hairs of the bees, or heavy metals in the nectar of a flower are absorbed directly by the bees and thus enter the honey.

Other pollutants include:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that are deposited in animal fats and are found primarily in fish, shellfish, and dairy products. PCBs can be released into the environment through spills and leaks from electronic machinery. Once in the environment, PCBs enter our food chain by binding to soil, air and water. The Tentamus Group uses gas chromatography (GC) to detect PCBs in food.
• Foods may also contain MOSH/MOAH (petroleum saturated/aromatic hydrocarbons) as a result of the migration lubricants used in the packaging of a food product. Mineral oil hydrocarbons (MOH) are generally extracted from crude oil during the refining process. Since MOH contain mutagens and carcinogens, Recommendation (EU) 2017/84 provides guidance on the minimum performance requirements for analytical methods used in monitoring contamination with MOSH/MOAH.
• ITX (isopropylthioxanthone) levels in foods are also repeatedly detected. This organic chemical compound can enter food in a variety of ways: It is contained in printing ink and can be transferred from the outside of a carton to the inside, which comes into contact with the food when the printing carton is rolled up. The BfR has evaluated ITX in food as a genotoxic substance due to its mutagenic properties. ITX frequently occurs in milk and cloudy fruit juices, e.g. apple and orange juice.
• Dioxins are POPs that are found everywhere in the environment. They are emitted into the atmosphere by burning wood, coal, or oil. Dioxins then settle in soil and water consumed by animals. Dioxins are stored in animal fats, which are then consumed by humans. Dioxins are highly radioactive and are not digested, although their radioactivity subsides within 7-11 years after ingestion.
• Furans are POPs formed during the processing of heated foods. They are commonly found in ready-to-eat foods or in jars/cans. They are formed in the environment by accumulating in soils and sediments of water bodies. They enter the food chain through remobilization.

3. Food Contamination with Allergens

Allergens and intolerance-triggering substances pose a health risk to certain consumers. Food often contains allergens such as peanuts or egg residues.

According to the FIC, there are 14 main allergens:

1. Celery
2. Cereals containing gluten
3. Crustaceans
4. Egg
5. Fish
6. Lupine
7. Milk
8. Molluscs
9. Mustard
10. Nuts
11. Peanuts
12. Sesame
13. Soy
14. Sulfites

There are currently nine major allergens listed in the US.

Cross-contamination can occur when a small amount of a food allergen accidentally gets into another food. Even trace amounts of allergens can trigger an allergic reaction and therefore need to be tested.

ELISA tests are used to test antibodies in the blood for allergen sensitivity. ELISA tests are performed using highly specific antibodies that react with antigens that are allergenic substances. This is often done as a precautionary measure to protect against possible allergic reactions.

PCR (polymerase chain reaction) is a microbiological method that makes millions to billions of copies of a DNA sample, allowing scientists to study it in detail. PCR testing allows the determination of the presence of a specific animal or plant DNA strand in a food and is therefore used to detect germs, viruses and GMOs in a food. PCR is often used as a complement to ELISA testing because it is very sensitive in picking up trace amounts of celery and fish. However, it has problems with cross-contamination with other foods such as milk and eggs, as these allergens would register as cow or chicken DNA.

4. Food Contamination with Mycotoxins

Mycotoxin contamination occurs at various stages of crop production. Mycotoxins are metabolites of molds that can have a toxic effect when consumed. Primary mycotoxin contamination occurs when plant raw materials are infested with molds. Secondary contamination occurs when raw materials become moldy during storage or transport.

In Regulation (EU) No. 2023/915, the EU sets the legal maximum levels for mycotoxins in food.

5. Food Contamination with Microorganisms

Food contains a variety of microorganisms that can be transferred from one source to another in the absence of food hygiene. An example of this is the transfer of germs from a raw food to a cooked food through cross-contamination. The types of microorganisms that can contaminate food include:

• Staphylococcus Aureus
• Salmonella
• E.coli
• Clostridium Perfringens
• Campylobacter

The above bacteria and other microorganisms are examined in microbiological tests within the Tentamus Group. Since there is an abundance of harmful microbes that can make their way into food, microbiological testing can prove the harmlessness and marketability of a product.

How can food contamination be prevented with HACCP concepts?

HACCP (Hazard Analysis Critical Control Point), also known as hazard analysis and critical control points, is a preventive system designed to increase food safety and ensure food hygiene. HACCP guidelines protect food from biological, chemical and physical influences.

Within the EU, HACCP was introduced in 2004 and has been mandatory since 2006 under the following regulation (Regulation (EC) No. 852/2004 on food hygiene).

HACCP aims to identify and then prevent hazards in food. Hazards may include microorganisms, chemicals or allergens that enter the food. Storing food at undesirable temperatures or touching products with hands can also trigger dangerous pathogen growth in food (see >> Our shear points in contamination analysis<<).

HACCP concepts are implemented using 12 steps and 7 principles. The 7 principles are:

1. Conduct a hazard analysis in which all potential hazards are identified
2. Determination of critical control points
3. Establish critical limits
4. Establish a system to monitor the control points
5. Taking corrective action if the limits are exceeded
6. Review of the HACCP concept and revision of the concept if necessary
7. Documentation of all HACCP measures

Implementing a HACCP system can be a challenge for food companies. For this reason, the experts of the Tentamus Group are available to advise you, support you in creating an HACCP concept and optimize it in the future.

The following foods can cause food poisoning and should be tested frequently:

• Meat and sausage products
• Eggs
• Meat
• Fruits and vegetables
• Fish
• Dietetic food

These products receive special attention within Tentamus, as products containing impurities pose an increased risk to the consumer. Product recalls are avoided through regular inspections. This helps you as a manufacturer to save costs and avoid damage to your image.

Two methods are used to investigate food contamination, the sampling method and the continuous method:

• In the random sampling method, food is randomly selected from a batch and tested for quality and safety.
• In the continuous method, food is inspected on a regular basis. This is usually done on vegetables to measure mycotoxins or heavy metals, for example.

How are samples selected for testing?

When selecting products to be tested in Tentamus laboratories, some food samples are randomly selected from a population. If a 1 kg vegetable sample is needed for testing, they are selected from different locations or containers to increase the accuracy of the results.

The customer can decide whether to send the samples themselves or have them collected by one of Tentamus’ sample pickers. If the customer chooses to send in the products themselves, they are responsible for ensuring that the samples are selected as randomly as possible.

To maintain the freshness of the products during the transportation process, Tentamus uses airtight plastic bags to prevent drying out and contamination of the products. A cold chain is also used for goods that need to be refrigerated, using ice packs or dry ice.

Tentamus has a global network that analyzes food for contaminants and pollutants. Although the Tentamus Group is now a global company, it prides itself on supporting customers locally by offering to pick up samples that are tested in a short time using state-of-the-art equipment.

The following laboratories of the Tentamus Group offer isotope analysis: