Services in the field of microbiology
Microbiology in food and fodder
The microbiology laboratory at the SYNLAB Food Institute assists customers from the food and fodder industries in the quality control of their products. Our services cover a broad range of food-related product groups. We also perform microbial analyses on:
- raw materials in food production,
- drinking water,
- packing materials,
- drinking water for animals and fodder.
The second focus of our analyses is, among others:
- the detection of pathogenic microorganisms, indicator germs and food spoilers
- analysis for technically desired microorganisms
- provocation tests to check the shelf life of preserves
- inhibitor tests on food and fodder (screening for antibiotically active substances)
The analyses are performed according to recognised methods (ASU §64 LFGB, DIN/EN/ISO, European Pharmacopoeia). Besides the traditional (cultural) methods, we are also able to apply modern techniques such as ELISA and PCR.
Any self-monitoring system by a food manufacturer to ensure food safety must always place a significant focus on the elimination of pathogens, i.e. adherence to the relevant limit values specified by European and national food legislation.
Among other things, we offer analyses for the detection and/or counting of the following germs with pathogenic properties in order to assist in this area of consumer protection:
- Bacillus cereus
- Thermophile campylobacter (C. jejuni, C. coli)
- Clostridium perfringens
- Enterohaemorrhagic (EHEC) and shiga toxin-producing (STEC) Escherichia coli
- Listeria monocytogenes
- Staphylococcus aureus
- Salmonella enteritidis
- Yersinia enterocolitica
In this context, it is also possible to determine an elevated resistance to antibiotics among certain microorganisms. MRSA (methicillin-resistant Staphylococcus aureus) and ESBL (extended-spectrum-ß-lactamase positive bacteria).
The detection or exclusion of other pathogens may be possible on request.
Consumers may suffer foodborne infections or food poisoning after consuming products contaminated with the bacteria listed above:
in foodborne infections, pathogenic microorganisms are carried by food into the gastrointestinal tract, where they cling to the walls, proliferate and then penetrate the cells. Following a varying incubation period they will then produce symptoms due to damage caused by the pathogen itself or the defensive reactions of the human body.
Health impairment precipitated by the toxins that the bacteria produce is called poisoning. Bacterial toxins are often proteins or their constituents that take effect in the intestinal tract. They are known as enterotoxins. These toxins usually form as the bacteria proliferate in the food. All it then takes is for a person to consume the food contaminated with toxins. It is not even necessary for any live pathogen cells to be present.
A 24-hour express analysis service is available on request to detect salmonella, EHEC/STEC and Listeria monocytogenes. An extremely elaborate procedure, this analysis uses a biomolecular method (PCR) to detect the pathogen’s DNA.
Food is described as having spoiled when adverse changes have made it unfit for human consumption. The proliferation of microorganisms and their metabolic activity are among these adverse changes. Often, although not always, these processes are accompanied by sensory changes like discolouration, gas formation and swelling, putrescence, acidification or fermentation.
Microorganisms arranged in groups, which we gladly analyse on your behalf, are frequently responsible for this spoilage:
- lactic and acetic acid bacteria
- yeasts and moulds
- aerobic (bacilli) and anaerobic (Clostridia) sporulators
Indicator germs (‘indicator microorganisms) are used in food analysis to critically assess process hygiene, i.e. to detect contamination, and to locate its possible source. In this area, the following are considered indicative of:
- insufficient product heating: Enterobacteria
- insufficient packaging hygiene: lactic acid bacteria
- insufficient personal hygiene: staphylococci and/or lactic acid bacteria
- fecal contamination: Escherichia coli and fecal coliforms (thermo-tolerant coliform bacteria), enterococci, i.e. Enterobacteria (predominantly in animal foods)
- soiling with earth, environmental contact: Clostridia and/or Enterobacteria (predominantly vegetable foods)
The detection of indicator germs as evidence of hygiene deficiencies in the manufacturing process, i.e. any increase in the number of these microorganisms in the product beyond a certain limit, may necessitate additional analyses and/or countermeasures under food law.
Technically desired microorganisms should also be mentioned in the production of foods. They are present as natural flora, i.e. are added in the form of starter cultures or technical additives, and are needed for certain ripening and refining stages in specific products. Examples include
- lactic acid producers that promote fermentation (lactobacilli, micrococcae)
in dairy products like yogurt and cheese, raw sausage or raw ham, in sauerkraut and in probiotic products to supplement the diets of humans and animals.
Other applications are
- Mould cultures on certain types of sausage and cheese.
In some cases yeast will also be added as desirable microorganisms, for instance to mature air-dried, raw cured products. The use of
can be considered one of the oldest forms of biotechnology.
In individual cases by request, we are able to determine the precise species of a bacterial or fungal isolate obtained during food analysis. This species is determined using downstream biochemical or biomolecular analysis or by mass spectrometry.
Hygiene requirements are indispensable in food production. There are various ways to investigate production hygiene.
1. Environmental monitoring
Environmental monitoring involves determining the surface germ content of work surfaces and tools (cleaned and/or disinfected, i.e. during production), as well as the airborne germ content. The following methods are available to perform the analysis:
- adhesive film testing, usually on larger, even, solid surfaces.
- swabs of all surfaces and tools with quantitative (germs per cm²) or semi-quantitative analysis (0.1-10; 11-100; >100 germs per sampled surface)
- traps (bowls with a nutrient medium left standing in the production site for a certain period to measure the airborne germ content)
- airborne germ content using special collectors
We provide all materials needed for sampling. Our qualified employees can also handle sampling itself.
2. Personal hygiene
Besides regular staff hygiene training, it is also advisable to monitor personal hygiene in sensitive production areas in order to prevent one of the main germ pathways into the food production process. The following analyses are suitable:
- adhesive film test on hands and/or work clothes to ensure adequate cleaning
- stool analysis to exclude diseases, i.e. to identify persons with clinically relevant carriers
We also provide all the materials needed for sampling.
1. Fodder microbiology
The following aspects are important to livestock fodder:
- detection of salmonella,
- exclusion of antibiotic performance enhancers (inhibitor test) or
- assessment of contamination with yeast, mould and Clostridia
(among others within the framework of QA fodder monitoring).
The analysis can be expanded to include Enterobacteri, as well as E. coli and other bacteria in order to evaluate the general hygiene status of the fodder, especially if it is intended for pets.
2. Assessment of stable hygiene
Our experience has shown that special analyses are urgently advisable to monitor hygiene management in livestock production, as it represents the primary production area for food. This includes:
- inspection of cleaning and disinfection in stables before animals are placed in/returned to the stable,
- sampling of purchased animals to exclude contagions and
- direct pathogen detection as required under law, e.g. before slaughtering poultry (droppings, sock swabs).
Quick, purposeful and effective countermeasures can be taken on this basis in the event of any positive findings.