EN ISO 6888-2:2021 PDF

Overview

EN ISO 6888-2:2021 - "Microbiology of the food chain - Horizontal method for the enumeration of coagulase‑positive staphylococci - Part 2" specifies a horizontal enumeration method for coagulase‑positive staphylococci (notably Staphylococcus aureus) using rabbit plasma fibrinogen agar (RPFA). The method counts colonies on RPFA after aerobic incubation at 34 °C to 38 °C and is intended for testing materials across the food chain, including food and feed products, environmental samples in production/handling areas, and primary production samples.

Key topics and requirements

• Method principle: enumeration of coagulase‑positive staphylococci by colony counting on RPFA medium under aerobic incubation.
• Incubation conditions: aerobic incubation at 34–38 °C; standard incubation time referenced as 24 h ± 2 h where applicable.
• Culture medium: use of rabbit plasma fibrinogen agar (RPFA) with defined performance testing (see Annex B).
• Preparation and procedure: test portion, initial suspension, serial dilutions, inoculation, incubation and colony counting workflow (flow diagram in Annex A).
• Performance evaluation: interlaboratory study results, repeatability and reproducibility limits included for method validation.
• Quality and standards alignment: method aligned with ISO 7218 laboratory practice and requires consideration of ISO 11133 for culture media preparation/performance. References to sampling standards and updated bibliography are included.
• Scope limitations: designed as a horizontal method applicable across diverse food-chain matrices; some products (e.g., strong background microbiota or atypical colony formers) may require minimal, justified adaptations.
• Safety: warning that testing must be performed in properly equipped labs under skilled supervision with appropriate biosafety and waste disposal.

Applications and users

• Who uses it: food and feed microbiology laboratories, quality control teams in dairy, meat and fermented‑product industries, regulatory and surveillance labs, and academic or contract testing facilities.
• Practical applications:
  • Routine monitoring of Staphylococcus aureus counts in food and feed.
  • Environmental monitoring in processing and handling areas.
  • Examination of fermented products and raw‑milk cheeses or raw meat products where technological staphylococci (e.g., S. xylosus) and atypical colonies occur.
  • Cases where Baird‑Parker agar may not clearly differentiate target colonies due to background flora.

Related standards

• ISO 6888‑1 (detection/enumeration - equivalent status for many uses)
• ISO 6888‑3 (other methods in the series)
• ISO 7218 (general microbiological laboratory practice)
• ISO 11133 (media preparation and performance testing)
• Relevant national sampling standards and ISO sampling references

This standard is essential for reliable, standardized enumeration of coagulase‑positive staphylococci in the food chain and supports compliance, product safety assessment, and HACCP/environmental monitoring programs.