Food contaminated with pathogenic bacteria may pose a serious health risk to the consumer. Thus the control of pathogens throughout the whole production chain is crucial to ensure consumer protection.
Pathogenic bacteria can trigger dangerous cases of food poisoning and must therefore not be present in food at all or at least a specific number per gram of food must not be exceeded. Particularly untreated fruits, vegetables, raw meat products, raw milk products as well as water are often sources for possible bacterial infections. Food safety is therefore a demanding challenge for all parties involved, especially in the area of quality assurance at primary production sites, food retailing and also for governmental authorities.
Together with Salmonellosis, Campylobacteriosis is one of the most significant diarrhoeal diseases worldwide. The strong increase of Campylobacter-enteritis is encouraged by the broad spread of the bacterium in different species of wild or farm animals as well as pets (birds and mammalians). As a commensal in the gut of poultry, Campylobacter reaches the food chain of humans via these animals. Additionally, other foodstuffs as milk, ground meat and drinking water can act as transmission pathways for the pathogens. Campylobacter is released by numerous hosts in high quantities to the environment and reaches the human body via contaminated foods. The infective dose to get to a Campylobacter enteritis is relatively low. It does not need more than 500 germs to get to an infection. From approximately 15 known Campylobacter species, mainly C. jejuni and C. coli are known to be causes for human gastroenteritis.
Clostridium species are gram-positive, spore-forming bacteria and are present almost everywhere in the environment. Some Clostridium species are of importance as pathogens, including Clostridium botulinum, Clostridium perfringens and Clostridium estertheticum. If food is not cooled sufficiently, it can result in a contamination, which can cause serious illnesses. The bacteria are heat-resistant and thus, can also be contained in thoroughly heated food products.
Legionella are a genus of gram-negative, rod-shaped bacteria that live in the water. They are considered as potential human pathogens. The Legionella species that is mostly responsible for illnesses in humans is Legionella pneumophila; it triggers the so-called legionnaire’s disease (legionellosis). The disease is usually transmitted through contaminated drinking water.
Listeria can be found in almost all areas of life. It is possible to assess the risk of contamination via quantitative detection to ensure that, if necessary, preventive measures can be taken. Listeria monocytogenes, in particular, is considered a major cause of food poisoning, possibly resulting in the development of sepsis, meningitis and encephalitis.
Salmonella is ranked among the most important initiators of cases of food poisoning. The WHO estimates more than 16 million global infections per year, and more than half a million cases are fatal. Salmonella are found in raw food such as eggs, meat and milk. The hazard potential is high, particularly in food that should only be slightly heated or not at all heated (e.g. raw milk cheese, raw sausage, chocolate, ice cream). In today’s mass animal farming industry, contaminations with Salmonella can hardly be avoided. Therefore, effective quality control with reliable test methods is important. For this purpose, we offer a series of different test systems, for the hygienic control of surfaces as well as for the analysis of food.
Staphylococcus aureus is a ball-shaped bacterium which can be observed as a grape-like clustered organism under the microscope. Cells are sized between 0.8 and 1.2 µm, Gram-positive and non-motile. S. aureus is a natural commensal of humans which lives on skin and upper airways and doesn’t cause diseases in general. In case of infections with pathogenic strains or in immunodeficient persons, S. aureus is able to cause skin infections and abscesses but also life-threatening diseases as pneumonia, meningitis, endocarditis, or toxic shock syndrome (TSS).
One reason for the facultative pathogenicity of S. aureus is its ability to form enterotoxins (SET), which can accumulate in contaminated food and cannot be inactivated totally by heat treatment. Contamination of foodstuffs with S. aureus is almost always caused by humans (hands, sneezing, coughing). S. aureus is therefore considered as indicator for poor personal hygiene.
Beside its relevance for food hygiene, S. aureus also plays a significant role in hospital hygiene. Especially strains of S. aureus which have acquired resistances against common antibiotics the so-called „methicillin resistant Staphylococcus aureus” (MRSA) might pose a non-assessable danger as they are difficult-to-treat.
The bacteria Escherichia coli (abbreviated E. coli) is a natural component of the intestinal flora in humans and animals and it is usually harmless. However, there are pathogenic strains that can cause serious infections. One of these pathogenic strains is known as enterohemorrhagic Escherichia E. coli (“EHEC”). These bacteria build the toxic substances verotoxin or shiga toxin and are also known as verotoxin-producing E. coli (“VTEC”) or shiga toxin-producing E. coli (“STEC”). Infections with STEC/VTEC are ranked as one of the most common food-related bacterial diseases that can even result in death. Sources of contamination mainly include raw meat and unpasteurized dairy products.
The group of Vibrio spp. includes pathogenic microorganisms which can cause serious infections after consumption of contaminated food. In diseases correlated to seafood, Vibrio spp. is one of the major causes of gastroenteritis, wound infection and sepsis. Additionally, in serious infections with the potential for epidemics such as Cholera, Vibrio spp. is causative.
The bacterium Vibrio parahaemolyticus naturally inhabits coastal waters and is present in higher concentrations during summer. The organism is halophilic or salt-requiring. Therefore, Vibrio parahaemolyticus is found in marine environments, seafood and the feces of patients with acute enteritis. Vibrio parahaemolyticus-associated gastroenteritis is the infection caused by this organism.
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