Microbiological testing includes methods for the detection of microorganisms such as bacteria, viruses, yeasts or molds. These detection methods can be applied to various sample types, such as food, drinking water, cosmetics, dietary supplements and pharmaceutical products.
Microbiological testing aims to determine the microbiological status of the tested sample. Thus, the presence of microbiological contaminations can be excluded and product safety can be guaranteed.
Service overview of our microbiological laboratories
The laboratory network of the Tentamus Group offers its customers the following services in the industry of microbiology:
- Microbiological testing in accordance with Regulation (EC) No. 2073
- Determination of the microbiological status of food, as well as detection of pathogenic germs such as Salmonella, Listeria monocytogenes and Campylobacter
- Rapid methods (Vidas) for Salmonella and Listeria monocytogenes
Performance of follow-up tests to determine or check compliance with the best-before date (BBD) or the use-by date
- Microbiological incoming goods inspections for animal or plant raw materials or semi-finished products
- Microbiological inspection of the cleaning and disinfection status of equipment and surfaces
- Sampling and testing of drinking water in accordance with the Drinking Water Ordinance for e.g. Legionella, Escherichia coli and Pseudomonas aeruginosa
- Microbiological examination of cooling tower water
- Pest infestation of dried fruits and nuts
- Verification of the designated trade classes for fresh and frozen poultry and eggs
- Testing of eggs for freshness by means of air chamber height, yolk index and Haugh units
- Microbiological cosmetic testing according to ISO methods and the European Pharmacopoeia
- Preservation stress tests
- Testing of non-sterile pharmaceuticals according to European Pharmacopoeia and GMP regulations
- Antibacterial activity of honey
- Testing of living biotherapeutics
- Pyrogen determinations
- Determination of genotoxicity
- Purity testing of bacterial cell banks
Microbiological testing of food and food supplements
Foodstuffs represent a focal point for microbiological investigations. With few exceptions, microorganisms in food are undesirable because they can cause food to spoil and sometimes lead to health hazards and illness for consumers. Food business operators must therefore take measures to prevent contamination of food with microorganisms during production and processing. This includes hygiene concepts according to the HACCP procedure (hazard analysis and critical control points) and the commissioning of a microbiological laboratory, as well as the deployment of well-trained personnel.
Please find further information about food safety in our blog articles:
Microbiological testing of drinking water
Strict regulatory requirements are set for drinking water not only with regard to substance-related limit values such as nitrate, nitrite, fluoride or lead, but also with regard to microorganisms. For example, the Infection Protection Act and the Drinking Water Ordinance stipulate that drinking water “must not contain any pathogens in concentrations that could endanger human health.”
In routine drinking water monitoring by microbiological laboratories, evidence is therefore provided by so-called “indicator organisms” for fecal contamination, such as Escherichia coli or enterococci, in the water sample.
If these numerically very common germs cannot be detected in a sample, it can be assumed that the less common but potentially more dangerous microorganisms are also not present in the sample.
Drinking water testing for legionella
In addition to microbiological testing for fecal contamination, testing for Legionella is another focus of drinking water analysis and monitoring. Legionella is a considerable health hazard, especially for immunocompromised persons. The disease caused (“Legionnaires’ disease”, legionellosis) can be fatal.
Legionella are transmitted by droplets. Infection occurs when they are inhaled in high numbers, e.g. through water vapor. Microbiological testing for Legionella is therefore required by law for the drinking water installations of many facilities. These include facilities that operate a large-scale system for heating drinking water, dispense drinking water as part of commercial or public activities, and where there are showers or other facilities for misting water. Such facilities include, but are not limited to, residences, hospitals, swimming pools, schools, and hotels.
However, operators of cooling towers, evaporative cooling systems and wet separators are also subject to extensive notification and monitoring obligations with regard to legionella in order to operate their facilities.
Microbiological testing of cosmetic products
Cosmetic products must be safe and harmless to health from the time they are placed on the market until they are used by the customer. The European Cosmetics Regulation VO (EG) 1223/2009 sets the legal framework for this. This health safety also includes the microbiological quality of a product. ISO 17516, the state of the art, specifies limit values for this.
In order to maintain sufficient microbiological product quality, it is necessary to establish a so-called microbiological quality management (MQM) in the plants. Components of a MQM are the industries research & development, industrial hygiene as well as quality control (QC).
Microbiological tests are required in all industries. These include:
- Control of the microbiological status
- Examinations according to ISO standards
- Examination by rapid method: results aerobic microorganisms and yeasts/molds within 3 days
- Total number of aerobic microorganisms/ g
- total number of yeasts and molds/ g
- specified microorganisms (P. aeruginosa, E. coli, S. aureus, C. albicans) in 1 g
- non-specified microorganisms such as Pluralibacter gergoviae, Burkholderia cepacia etc.
- Identifications by MALDI-TOF within 24 h
- Preservation load tests DIN EN ISO 11930
- Method of the European Pharmacopoeia (Ph.Eur.5.1.3)
- Method of the American Pharmacopoeia (USP)
- Customized specifications and microorganisms
- Repetitive exposure tests (multiple inoculations)
- Industrial hygiene
- Examination of swab samples and swab samples
- Testing of microbiological quality of air
- Testing of water quality
Some Tentamus Group laboratories also offer special rapid methods to provide customers with test results after 3 days. This includes:
- Testing for Salmonella, STEC/VTEC/EHEC using “real-time PCR”.
- Testing for Listeria monocytogenes using a rapid cultural method
- Germ identification by mass spectrometry (MALDI-TOF)
For further information on the safety of cosmetics, please see our blog article:
Microbiological testing of pharmaceuticals
Pharmaceuticals are subject to strict national and international regulations. Through our highly specialized pharmaceutical laboratories and scientists, we can optimally support you in the analysis of your pharmaceuticals.
Microbiology for pharmaceuticals includes the detection of microorganisms that may be present in raw materials, the production environment as well as in formulated products. Our pharmaceutical laboratories offer the full range of services, including testing of non-sterile products and substances:
- Microbial limit testing
- Microbial contamination (bioburden analysis)
- Sterility testing
- Determination of biological load (Ph. Eur. 2.6.12, ISO 11737-1)
- Pyrogen determination: bacterial endotoxin test (Ph. Eur. 2.6.14) and monocyte activation test (Ph. Eur. 2.6.30)
- Microbiological testing of live biotherapeutics (Ph. Eur. 2.6.36, Ph. Eur. 2.6.38)
- Purity testing of bacterial cell banks
- Bacteriophage analysis
- Determination of genotoxicity (AMES test, OECD TG 471)
- Microbiological testing of cosmetics according to CTFA or ISO standards
Further information about Testing of pharmaceuticals can be find here: Pharmaceutical Testing
How are samples taken for microbiological testing?
Sampling is an essential and critical step that has a decisive influence on the significance of the results of the microbiological examination. Errors in sampling can seriously reduce the significance of the microbiological examination, so that the purpose of the examination cannot be fulfilled. Therefore, sampling should only be performed by trained personnel. Another critical point is the controlled and timely transport of the collected sample for analysis to the contracted laboratory.
The microbiological laboratories of Tentamus offer you a convenient service for sample collection and pick-up.
Overview of detectable germs and pathogens
In addition to the examination of the total bacterial count, the range of services offered by our laboratories includes microbiological examinations and detection methods for the following germs and pathogens:
- Aerobic mesophilic spore formers
- Bacillus cereus
- Candida albicans
- Clostridium perfringens
- Coliform germs
- Bile salt tolerating gram-negative bacteria
- Yeasts and molds
- Coagulase-postitve staphylococci
- Listeria monocytogenes
- Lactic acid bacteria
- Pseudomonas spp.
- Salmonella spp.
- Shigella spp.
- Sulfite-reducing Clostridia and their spores
- Staphylococci, enterotoxin, enterococci
- Staphylococcus aureus
Determination of the total bacterial count
Aerobic mesophilic germs include many different microorganisms of various origins. A small number of aerobic mesophilic germs is normal on almost all foods. However, if the total plate count is elevated in the tested sample, this may indicate a hygiene deficiency in the production or processing process or may be considered a spoilage indicator. Thus, the total plate count determined in the microbiology laboratory allows conclusions to be drawn about the quality and safety of the tested product.
Detection of yeasts and molds
Yeasts and molds are typical spoilage pathogens whose demands on your environment differ from those of most microbes. Yeasts and molds also grow under lower temperatures or in environments with a lower water activity value (aW value), a measure of the available water in a food. Molds are of particular health concern because of the mycotoxins they produce, which can cause allergies and some of which are carcinogenic.
Detection of coliforms
Coliform germs, which include the genera Escherichia, Citrobacter and Klebsiella, are an important hygiene indicator for drinking water and food. The presence of coliform germs in a sample is a typical indicator of poor hygiene.
Pathogens of food poisoning and foodborne illnesses
Clostridium perfrigens, Bacillus cereus, Staphylococcus aureus and Shigella can cause severe food poisoning (also known as food intoxication) through the toxins they produce, which are usually manifested by the symptoms of vomiting and diarrhea within a few hours of ingestion.
In contrast, Salmonella spp. or Listeria monocytogenes, for example, can cause food infections, whereby the bacteria ingested through contaminated food multiply in the intestine and, after a specific incubation period of usually a few days, trigger symptoms such as abdominal pain, diarrhea, and vomiting, often in conjunction with fever, which can lead to severe courses of illness in certain patient groups (including the elderly and patients with weakened immune systems).
Inoculation tests, so-called challenge tests, can be used to simulate the growth behavior of Listeria monocytogenes in a product and thus determine the growth potential of this highly pathogenic germ in the product under investigation. These tests are necessary to meet regulatory requirements for product safety with respect to Listeria monocytogenes.
More information can be found here: Listeria Challenge Test