Causes
of Food Contamination

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 basic prin­ci­ples of the Euro­pean Union concerning food cont­a­m­i­nants are laid down in Council Regu­la­tion 315/93/EEC. Maximum levels for certain cont­a­m­i­nants are set in Commis­sion Regu­la­tion (EC) 1881/2006.

Our focus on
food contamination analysis

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 (EC) No. 1881/2006, 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 (EC) No. 1881/2006, 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.

HACCP Concepts –
Self-monitoring system to avoid and reduce food contamination

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.

What foods
should be routinely tested for food contamination?

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.

Overview of
laboratories for the analysis of contamination of the Tentamus Group

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:

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