Staphylococcus aureus

What Is Staphylococcus aureus?

Staphylococcus aureus is a bacteria commonly found on human skin and nasal flora. It produces a heat-stable enterotoxin when it multiplies in food; Since this toxin is not destroyed by cooking, it can cause poisoning even if the bacteria dies. ISO 6888 defines the enumeration of coagulase-positive staphylococci.

Purpose of Staphylococcus aureus

The aim is to determine whether the product has been exposed to contamination caused by hand contact during production and whether conditions that would allow toxin formation have been experienced.

Which Products Is Staphylococcus aureus Applied To?

Hand-prepared ready meals and pastry products
Cheese and dairy products
delicatessen products
Ice cream and cream products
Personnel hand and surface swabs

In Which Sectors Is Staphylococcus aureus Used?

FoodDrinkAgricultureRetailYem

Standards Related to Staphylococcus aureus

ISO 6888-1 (Baird-Parker agar)
ISO 6888-2 (rabbit plasma fibrinogen agar)
ISO 6888-3 (EMS technique at low numbers)
EN ISO 19020 (stafilokokal enterotoksin tespiti)

Staphylococcus aureus Conditions

Method: Colony counting technique; EMS for samples with low numbers expected
Culture medium: Baird-Parker agar (egg yolk-potassium tellurite added)
Verification: Coagulase assay on typical colonies
Toksin: Enterotoxin detection by immunoenzymatic method on request

Equipment for Staphylococcus aureus

Class II biosafety cabinet
Temperature-controlled incubators
Stomacher (peristaltic homogenizer) and sterile bags
Autoclave and dry air sterilizer
Colony counting apparatus and microscope

Sample Requirements for Staphylococcus aureus

The sample must be sent in its original, unopened packaging.
Products that require a cold chain must be delivered with a cooler and without breaking the chain.
Aseptic sampling rules must be followed; The container must be sterile.
Batch, production date and expiration date information must be reported with the sample.
The amount required for analysis varies depending on the product type; Confirmation must be received before shipping.

Duration of Staphylococcus aureus

Count and coagulase verification takes several days. Enterotoxin analysis is a separate study and adds to the time.

Staphylococcus aureus Procedure

1The sample is weighed and homogenized and diluted.
2Broadcasting is done on Baird-Parker agar.
3Plates are incubated at the defined temperature and duration.
4Typical colonies (black, shiny, with clear zones) are counted.
5Coagulase test is applied to selected colonies.
6The result is calculated based on the confirmed colony rate.

Staphylococcus aureus Acceptance Criteria

The legislation, not the method, determines whether the result will be considered appropriate or not. The relevant communiqué of the Turkish Food Codex, EU 2073/2005 and 1881/2006 and the specification of the buyer company define different limits depending on the product group; The report gives the measured value and takes the limit from the applicable legislation.

Evaluation of Results

The result is compared with the process hygiene criterion of the product group. Toxin analysis may also be ordered when high counts are found; The presence of toxin means that the product is unfit for consumption.

Staphylococcus aureus Report

Sample description, batch/lot information and arrival conditions
Sampling method (if taken by the laboratory)
Applied analysis method and reference standard
Analysis date and incubation conditions, if any
Result and its unit
Measurement uncertainty (if requested)
A statement that the result applies only to the specimen submitted for testing

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Turkish Food Codex Microbiological Criteria Regulation
EU 2073/2005 — microbiological criteria for foodstuffs
Law No. 5996 on Veterinary Services, Plant Health, Food and Feed

Food Testing — What Does This Testing Field Cover?

The section below describes the field that the Staphylococcus aureus test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Food testing shows that a product is safe for consumption and contains what its label states. The family works along three axes: microbiological safety, chemical safety and nutritional composition. All three require different laboratory infrastructure, a different body of methods and a different turnaround time.

The most distinctive feature of the field is TIME PRESSURE. A steel specimen can wait on a shelf; a raw milk or fresh meat sample cannot. The time the sample was taken, the transport temperature and how long it takes to reach the laboratory directly determine the validity of the result. In food microbiology the cold chain record is therefore an inseparable part of the test report.

On the microbiological side there are two different questions and they must not be confused. DETECTION of a pathogen is a qualitative question: is Salmonella present in the sample or not? ENUMERATION of indicator organisms is a quantitative question and an indicator of production hygiene. The absence of a pathogen in a product does not show that hygiene is good; if the total mesophilic aerobic count is high, there is a problem in the process.

On the chemical side, pesticide residues, mycotoxins, heavy metals, additives, veterinary drug residues and process contaminants (acrylamide, furan, PAH) are measured. Multi-residue methods in this area (QuEChERS-based LC-MS/MS and GC-MS/MS) can screen hundreds of active substances in a single analysis; limits are defined separately for each product–substance pair.

On the composition side, protein, fat, moisture, ash, fibre, sugar profile, fatty acid composition, vitamin and mineral content are determined. These values are the basis of the nutrition declaration on the label and the tolerance ranges are defined in legislation — the difference between the declared value and the measured value must stay within that tolerance.

There is NO CE marking on food, and this shapes how the field works. Conformity is demonstrated through operating a HACCP-based food safety system, complying with labelling rules and not exceeding contaminant, residue and microbiological limits. A test result produces evidence not for a certificate but for a functioning system.

Allergen management carries particular weight. The presence of an undeclared allergen in a product is one of the most frequent causes of food recalls. Analysis here runs together with cleaning validation: it is shown that the line has been cleaned adequately after a production run containing an allergen and that the risk of cross-contamination is under control.

Voluntary schemes have become effectively mandatory in this field. Retail chains require their suppliers to hold a certificate under a GFSI-recognised scheme (BRCGS, IFS, FSSC 22000); without it, getting onto the shelf is practically impossible.

Method groups in this field

Pathogen detection
Detection of Salmonella, Listeria monocytogenes, Campylobacter, Cronobacter and Shiga toxin-producing E. coli; culture-based and molecular methods.
Indicator counts
Total mesophilic aerobic count, Enterobacteriaceae, coliforms and E. coli, coagulase-positive staphylococci, yeasts and moulds, lactic acid bacteria, sulphite-reducing Clostridia.
Pesticide and veterinary residues
Multi-residue screening by LC-MS/MS and GC-MS/MS with QuEChERS extraction.
Mycotoxins and contaminants
Aflatoxins, ochratoxin A, deoxynivalenol, patulin; heavy metals (ICP-MS), acrylamide and PAH compounds.
Nutritional composition
Kjeldahl protein, fat and fatty acid profile, moisture, ash, dietary fibre, sugar profile, vitamin and mineral analyses.
Allergens and authenticity
Gluten, milk, egg, nut and soy allergen analyses; molecular methods for species identification and adulteration detection.

Commonly confused in this field

Sampling is half the result. A sample transported at the wrong temperature or delayed gives an invalid result even if it is analysed correctly in the laboratory.
The absence of a pathogen does not show that hygiene is good; indicator counts give separate information and the two are read together.
A result from a sample taken from a lot can be generalised to the whole lot only if the sampling plan was set up statistically.
Limits are defined in separate regulations by product group and are updated regularly; a conformity decision based on an outdated limit table may be wrong.
For exports, the limits of the destination country may differ from EU limits; the same product may be compliant in one market and non-compliant in another.

Which decisions these results support

Verification of the HACCP plan and process monitoring
The basis for the nutrition declaration and allergen information on the label
Health certificates before export and compliance with destination market limits
Supplier and lot-based acceptance control
Shelf-life studies and determining storage conditions
Producing evidence for audits under GFSI-recognised schemes

Related Tests

Frequently Asked Questions About Staphylococcus aureus

Does cooking destroy the toxin?

It kills the bacteria, but staphylococcal enterotoxin is heat stable and does not break down at normal cooking temperatures. Therefore, it is essential to maintain the cold chain before the toxin is formed.

What is usually the source?

They are mostly the hands, nasal flora or injured skin areas of people working in production. Therefore, personnel hygiene and glove use directly affect this parameter.