EN ISO 4833-2:2013 PDF

Overview

EN ISO 4833-2:2013 - "Microbiology of the food chain - Horizontal method for the enumeration of microorganisms - Part 2: Colony count at 30 °C by the surface plating technique" specifies a horizontal laboratory method for enumerating microorganisms that grow and form colonies on the surface of a solid medium after aerobic incubation at 30 °C. The method is intended for foods, animal feeds and environmental samples from food/feed production and handling areas.

Key topics and technical requirements

• Principle: Surface plating of a defined test portion (or initial suspension) onto agar plates, incubation at 30 °C and colony counting to calculate cfu per g or mL. Plates with fewer than 300 colonies are used for calculation.
• Incubation: Aerobic, 30 °C for 72 h (± specified tolerances within the standard).
• Culture medium: Plate Count Agar (PCA) is specified as the non‑selective agar for surface counts; preparation, pH adjustment and quality/performance testing are covered.
• Sample preparation and diluents: Follow ISO 6887 and relevant specific product standards for test portion, initial suspension and decimal dilutions.
• Alternative plating: The standard includes an Annex A describing use of a spiral plater, a rapid surface plating option as an alternative to manual spread plating.
• Performance and limitations:
  • Applicable to heat‑sensitive organisms (e.g., psychrotrophs), obligately aerobic bacteria (e.g., Pseudomonas spp.), coloured or particle‑rich matrices where pour plating is problematic, and when colony differentiation on the surface is needed.
  • Limited applicability for some fermented foods and certain animal feeds - other media/incubation conditions may be more appropriate and predominant organisms in these matrices may not be detected effectively.
  • Results may differ from ISO 4833‑1 (pour plate technique) for some matrices.

Practical applications and users

This standard is used by:

• Food and feed microbiology laboratories for routine total viable count (TVC) by surface plating.
• Quality assurance / QC teams in food and feed manufacturing for product release, shelf‑life studies and hygiene monitoring.
• Regulatory agencies and inspection bodies for standardized enumeration methods.
• Environmental monitoring programs in food production and handling environments where surface counts are required.

Benefits include clearer colony morphology for differentiation, suitability for heat‑sensitive and particle‑containing products, and an option for faster processing via spiral plating.

Related standards

• ISO 4833‑1 (pour plate technique)
• ISO 6887 (sample preparation and dilutions)
• ISO 7218 (general microbiological guidance)
• ISO 11133 (culture media preparation and performance)

Keywords: EN ISO 4833-2:2013, colony count, surface plating, plate count agar, spiral plater, aerobic incubation 30 °C, food microbiology, enumeration of microorganisms.