Quality assurance:
trade classes,
vitamin content and preservatives

In order to classify food, especially fruit and vegetables, into trade classes, sensory tests are carried out. When determining the sensory properties of fruits and vegetables, there are three different commercial classes. These classes are as follows:

  • Extra class (H. Extra): fruits and vegetables are of perfect quality, without defects in their texture, shape, coloration and size
  • Commercial class I (H. I): the fruit or vegetable has slight deviations in shape, color or firmness. The product may have some bruises or scratches
  • Commercial class II (H. II): the fruit or vegetable has slight deviations in shape, color or firmness: the fruit or vegetable has obvious defects. Almost all organic products fall into this category

Tentamus Group laboratories also perform tests to determine the vitamin content of a food product. This is done with an HPLC device or by LC-MS/MS. According to the recommendations of the German Chemical Society (GDCh), vitamins A, D, E, B12, biotin and folic acid can deviate by 30% of the stated content. The tolerance for vitamins B1, B2, B66, C, pantothenic acid and niacin may deviate by 20% of the stated content.

LC-MS/MS can also be used to check for preservatives in foods and agricultural commodities. Preservatives include, but are not limited to, benzoates, nitrites, sulfites, and sorbates. Preservatives are used to extend shelf life or increase the sensory desirability of a product.


Origin verification food

Isotope analysis for
origin verification

Verification of origin by the method of isotope analysis is carried out on products whose origin is frequently misrepresented. Since foodstuffs consist largely of biological elements such as oxygen, carbon, hydrogen, nitrogen and sulfur, their stable isotopes can be compared with those of known reference samples.

In an isotopic analysis, the isotopic ratios of the biological elements are measured and compared with the ratios of samples of known origin. This results in detectable and specific isotopic patterns that allow verification of origin, thus reducing consumer deception due to erroneous origin labeling.

Article 26 (2) of Regulation (EU) No. 1169/2011 specifies the labeling requirements related to the declaration of origin or country of origin of a product.

Foods that are frequently adulterated have their own guidelines, such as honey. The declaration of origin information for honey are regulated in Directive 2001/110/EC.

Other food products frequently affected by adulteration and false origin declarations are:

  • Coffee
  • Tea
  • Edible oils
  • Herbs/spices
  • Tree nuts
  • Fruits
  • Vegetables
  • Fish
  • Meat
  • Wine

Isotope analysis also helps to ensure product traceability and develop appropriate traceability systems to provide consumers with high quality food.

What is an isotopic analysis and how is it used to verify origin?

Isotopes are atoms whose nuclei contain the same number of protons but differ in neutron number. Isotopes of an element behave chemically the same, but can differ in their mass number, which in turn leads to molecular variations. Almost every element has more than one isotope.

Example: Carbon-12, for example, would contain 6 protons and 6 neutrons, while carbon-13 contains 6 protons and 7 neutrons. Although carbon-12 is the lighter of the two isotopes, both are still considered carbon.

Because these variations occur due to product provenance, the product of a particular origin has a unique “isotopic fingerprint.” The patterns of product origin can be identified using isotope ratio mass spectrometry (IR-MS).

The isotopes analyzed in this process come from ecological ecosystems that form the basis of food webs. The most commonly analyzed isotopes in foods are carbon-13 (δ13C), sulfur-34 (δ 34S), and nitrogen-15 (δ15N), as well as deuterium (δ2H) and oxygen (δ18O).

Isotope ratios refer to the ratio of neutron imbalances within an element, i.e., the ratio between, for example, oxygen-18 and oxygen-16 (δ18O value) against international references (for oxygen, this is VSMOW). First, the sample is burned or pyrolyzed to convert the elements to the gas phase, e.g., sulfur becomes SO2 with the isotopic ratio of the sample. This ratio is analyzed using a mass spectrometer, which shoots a beam of electrons at the gas molecules, ionizing them. The mass spectrometer then uses electric and magnetic fields to direct the ions onto the detectors. Thus, the atoms of the bioelements can give the tester an indication of the product’s origin.

Food products with
protected geographical origin

The European Union has quality regulations to protect the reputation of regional products in order to promote traditional and agricultural activities.

For example, one food product that requires origin verification is Scotch whisky, as whisky cannot be sold as “Scotch” if it is not produced in Scotland. Another example is Noord-Hollandse Gouda cheese, which also has protected geographical indication status because its production is limited to Gouda in the Netherlands. Beelitz asparagus is also a protected product in the EU.

These and other products are tested in an isotope laboratory using mass spectrometry to ensure that the isotopes in the sample match isotopes in reference samples from the correct region.

Correct indication of origin on a food product’s label builds consumer confidence in the brand. Geographical indications of products are listed in Annex III of Regulation (EC) No. 110/2008.

What does the consumer associate with regionality?

A region has both spatial and socio-cultural boundaries. These can be geographically smaller than a nation state but larger than a municipality. In most cases, natural areas such as “the Alte Land,” Lake Constance and “the Spreewald” give a region its name.

Origin verification product quality food

How does Tentamus contribute to
ensuring the product quality of food?

The Tentamus Group has specialized laboratories around the world that perform isotopic analysis for origin verification. This reduces consumer deception by offering organic and origin verification.

The following analyses are performed within the Tentamus network to verify and ensure the quality of your food:

  • Determination of origin by isotopic analysis
  • Pollen analysis of honey (determination of origin)
  • Verification of the designated classes of table potatoes and fruits and vegetables
  • Determination of vitamin content (with LC-MS/MS)
  • Qualitative & quantitative determination of preservatives
  • Determination of morpholine and the other 7 amino alcohols
  • Pre-market Testing (6-24h)
  • Quality assurance in relation to honey and tobacco products

Food Fraud –
False Indications of Origin

Tentamus has also launched the Tentamus Center for Food Fraud (TCF²), which provides consulting services and analytical support in the detection of fraudulent activities in the food sector. The TCF² has state-of-the-art equipment that provides the most accurate test results and methods. This equipment consists of:

  • R-MS (isotope ratio mass spectrometry): determining the origin of a product by identifying its isotopic fingerprint.
  • LC-IRMS (liquid chromatography coupled with isotope ratio mass spectrometry): analyzes individual ingredients found in a food product to determine its unique origin.
  • LC-HRMS (liquid chromatography coupled with high-resolution mass spectrometry): often used to analyze honey for adulterants and other means of food fraud.
  • NMR (nuclear magnetic resonance spectroscopy): used to determine the structures of e.g. proteins, amino acids, lipid fractions and the mobility of water in food.
  • LC-MS/MS (liquid chromatography coupled with mass spectrometry): modern analytical method for identifying trace substances in food, e.g. allergens or pesticide residues.
  • NGS (next generation sequencing): examines the DNA and RNA structure of foods to determine genetic alterations.
    ICP-MS (Inductively Coupled Plasma Mass Spectrometry): Identifies contaminants and toxic elements in food, e.g. heavy metals.

Worldwide network for
product quality assurance

Tentamus has a large number of sites with isotope laboratories that have a proven track record of accurate traceability. These laboratories are part of the industry of instrumental analysis, testing potentially harmful substances in food for compliance.

An example of one of these toxins is pyrrolizide alkaloids, the content of which is often too high in dried and frozen herbs.

Overview of
Laboratories for the Food Verification of Origin of the Tentamus Group

The following laboratories of the Tentamus Group offer isotope analysis:

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