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A horse in cow’s clothing

Control is good, dual control even better. Blind trust in the food industry is not always the best idea. Dioxin, EHEC and the horsemeat scandal show how vulnerable safety of the food chain is in a globalised world and also highlights the continuously changing challenges facing food inspectors. Food inspection aims to protect consumers from potential harm caused by food and against fraud committed by the industry. In 2011, nearly 50,000 food samples were examined in Baden-Württemberg using chemical, physical and microbiological methods.

The CVUA Freiburg tests ready-to-eat food like lasagne for the presence of beef and horsemeat. © Hans-Ulrich Waiblinger, CVUA Freiburg

Health is our most precious asset. However, this does not stop us from wanting to have all kinds of food available year-round from anywhere in the world. People in primary production, processing and the distribution of foods make compromises that might negatively affect products and the consumers will be left standing.

Of all samples inspected in Baden-Württemberg in 2011, almost 17 percent did not conform with food safety requirements. Some of the products differed from the norm with respect to material and composition; others violated labelling requirements. 0.2 percent of the samples tested were rated as harmful to human health, amongst other things due to the presence of pathogens, large amounts of histamine and sharp objects. In around one tenth of the products tested, inspectors criticised the way the product was presented or labelled as being misleading for consumers.*  

Hans-Ulrich Waiblinger, head of department in the Chemical and Veterinary Investigations Office (CVUA) in Freiburg, sees it as his department’s duty to identify violations of regulations in the food industry. “Generally speaking, we are tasked with investigating and assessing the samples which are brought to us by the food inspectors. We need to make sure that products are not harmful to human health.” The CVUA examines the samples specifically for the presence of unwanted compounds, dioxins, added substances and bacterial and other contaminations. “While pathogens like Pseudomonas are omnipresent and present virtually no danger to humans, faecal pathogens like E. coli must of course not be present in food,” the expert says.

Product labelling of GMOs and allergens

Was it really German asparagus for sale in German supermarkets at the end of March? © Hans-Ulrich Waiblinger, CVUA Freiburg

Waiblinger’s work is mainly focussed on the identification of genetically modified organisms and allergens in foods. He mainly uses molecular biology methods for these analyses. “We focus on the optimisation of methods before they are used in routine investigations. Sometimes, we also develop entirely new methods,” Waiblinger said. 

Investigating the causes of the serious EHEC outbreak in Germany in May 2011 was a major challenge for the German food-safety authorities involved in finding the cause of the serious foodborne illnesses and deaths. At the start of the EHEC outbreak, which caused a huge scandal, there was no routine method available to be able to identify the pathogen in the sprouts and salads that were thought to have caused it. Four weeks later, German reference laboratories in cooperation with scientific institutes issued methodological procedures for tracking suspicious foods and for the identification of EHEC. They also advised against eating certain vegetables and salads and published preventive hygiene measures. 

Overall, says Waiblinger, the legal situation regarding food safety has become more stringent as knowledge has increased and as the flow of goods in global trade has changed considerably in recent years. The European Union has the most stringent GMO regulations in the world. The threshold levels of approved GM ingredients such as the Roundup Ready® soybean (RRS) have been set to relatively low threshold levels, requiring manufacturers to label products that contain more than 0.9% of GM soybeans. Moreover, food or feed must be completely free from even trace amounts of GM crops that have not been approved. In the EU, foods containing even trace amounts of allergens must be labelled accordingly and from the end of 2014 onwards, food businesses will also be required to provide such information on food sold unpackaged, in catering outlets, bakeries and butchers, for example.

Stable isotope analysis: are Reichenau cucumbers really grown on the island of Reichenau on Lake Constance?

The issue of origin and authenticity of foods is becoming more important. In addition to assessing the safety of foods for human consumption, the CVUA Freiburg also applies techniques to assess the authenticity and origin of food. According to information published by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, one in two Baden-Württemberg citizens buys ‘regional’ food. However, the term ‘regional’ is not protected and is often also used for produce that is not grown in the region. Are the apples we buy in local supermarkets really Lake Constance apples, are the cucumbers from the island of Reichenau, or is asparagus that can be bought as early as March from a German field or is it really from faraway Greece? Am I really eating local strawberries when I know that the weather in recent weeks has barely been good enough for them to ripen?

It is difficult to assess the authenticity and origin of foods using conventional methods because the area where crops are grown does not normally have an effect on their material composition. Front-line controls are carried out on fields where crops are grown; inspectors check whether the strawberries are still green and whether the delivery documents are ready. In addition to visual inspection, stable isotope analyses can be used to remove remaining doubts.

All foods are composed of the same chemical elements, including carbon, oxygen, hydrogen and nitrogen. These elements are present in different isotopes, which means that one and the same element can be present in different isotopic signatures (i.e. ratio of stable or unstable isotopes of particular elements found in a product under investigation). “Some isotopes are stable and do not degrade or decay like radioactive ones,” Waiblinger says. “The ratio of stable and unstable isotopes can differ in relation to the area where crops are grown. This ratio therefore enables us to draw direct inferences regarding the area where the crops are grown.” Deception is a big issue and the strategies to detect fraud therefore need to become more and more sophisticated.

Cow’s milk in feta cheese

Real-time PCR is used to assess the authenticity of food products. © Hans-Ulrich Waiblinger, CVUA Freiburg

Feta is a protected designation of origin product; only cheeses produced in a traditional way in some areas of Greece, and made from sheep’s or goat’s milk can use the name ‘feta’. However, around ten percent of the popular cheese sold in German supermarkets is made from cow’s milk, which is a lot cheaper than sheep’s or goat’s milk.* 

And yet another example, horsemeat was found in products that should have been made entirely from beef. Waiblinger sees food adulteration as an important and challenging issue facing the food industry and attaches great importance to putting measures in place and using techniques to avoid consumers being deceived. Quantitative real-time PCR (polymerase chain reaction), which is extremely sensitive, has been found to offer the best probability of success in determining the presence of unwanted ingredients. Quantitative real-time PCR is an approach based on standard (qualitative PCR), a biochemical technology used to amplify characteristic gene fragments. While conventional PCR only provides information on whether a sample contains sought-after DNA fragments or not, real-time PCR can simultaneously quantify a targeted DNA fragment. 

“Information about the quantity of unwanted ingredients is especially helpful in cases where we are searching for the causes of health risks,” Waiblinger says. The quantitative detection of products using real-time PCR involves the use of fluorescent dyes. An increase in DNA products during the PCR reaction leads to an increase in fluorescence; this increase can be measured in real time. “The increase in fluorescence intensity is related to the quantity of the targeted DNA in the sample under investigation, and therefore allows the concentration to be quantified,” Waiblinger explains. The application of this method promises excellent results in situations like the recent horsemeat scandal. 

Waiblinger believes that the application of nonspecific screening strategies for contaminants and illicit substances in food will gain in importance and also envisages that more computer scientists will be needed to deal with the huge amount of data that will be generated. The idea behind these strategies is to identify potentially harmful food before huge quantities of it reaches the consumer. Despite the availability of sophisticated analysis methods, it can be safely assumed that consumers are best advised to rely on their senses. “Our sense of taste will always play a major role in discovering unwanted food ingredients. We know fairly well from our own experience how certain foods should taste and could therefore base our decision on whether we buy them or not on our own assessment,” Waiblinger concludes. 

Source:

2011 Annual Report - ÜBERWACHUNG LEBENSMITTEL · BEDARFSGEGENSTÄNDE · KOSMETIKA · TRINKWASSER · FUTTERMITTEL, Baden-Württemberg Ministry of Rural Areas and Consumer Protection

Further information:
Hans-Ulrich Waiblinger
Chemical and Veterinary Investigations Office Freiburg
Bissierstr. 5
79114 Freiburg
Tel.: +49 (0)761 / 8855-151
E-mail: hans-ulrich.waiblinger(at)cvuafr.bwl.de

Website address: https://www.gesundheitsindustrie-bw.de/en/article/news/a-horse-in-cow-s-clothing