EN ISO 4833-1:2013 PDF

Overview

EN ISO 4833-1:2013 - "Microbiology of the food chain - Horizontal method for the enumeration of microorganisms - Part 1: Colony count at 30 °C by the pour plate technique" - defines a standardized, horizontal method for enumerating culturable bacteria, yeasts and moulds able to form colonies after aerobic incubation at 30 °C. The method uses the pour plate (poured plate) technique with Plate Count Agar (PCA) and is intended for food and animal feed products and for environmental samples taken in food/feed production and handling areas.

Key topics and technical requirements

• Principle: Mix a measured aliquot of sample or dilution with molten PCA in a Petri dish (poured plate), incubate aerobically at 30 ±1 °C for 72 h, then count colonies on plates with fewer than 300 colonies and calculate CFU per g or mL.
• Applicability: Suited to samples requiring low detection limits (e.g., below 10^2/g or 10^2/mL for liquids, or below 10^3/g for solids) and matrices prone to spreading colonies (e.g., milk likely to contain spreading Bacillus spp.).
• Culture media: Specifies use of Plate Count Agar (PCA) with defined components (enzymatic casein digestion, yeast extract, glucose, agar); dairy samples may require added skimmed milk powder. Media preparation, storage and performance testing follow ISO 11133.
• Diluents and sample prep: Uses diluents and procedures referenced in ISO 6887 for preparation of initial suspensions and dilutions.
• Quality and interpretation: Guidance on counting, calculation of results, precision, and interpretation (including critical difference). The method may yield different results than the surface plating method in ISO 4833-2.
• Limitations: Limited applicability for certain fermented foods and some animal feeds where predominant organisms may not be detected effectively; alternative media/incubation conditions may be preferable.

Applications and users

Who uses EN ISO 4833-1:2013:

• Food and animal feed quality assurance / QC laboratories
• Regulatory and inspection bodies for microbiological compliance
• Dairy, meat, produce, beverage producers for microbial load, shelf-life and hygiene testing
• Environmental monitoring teams in food production and processing plants
• Contract testing laboratories offering standardized colony counts

Practical uses:

• Routine total viable count (TVC) testing
• Raw material screening (e.g., milk)
• Hygiene and environmental surface monitoring
• Supporting shelf-life and spoilage assessments

Related standards

• ISO 4833-2 - Surface plating technique (may give different results)
• ISO 6887 - Sample preparation and diluents
• ISO 11133 - Culture media preparation and performance testing
• ISO 7218 - General requirements for microbiological examinations

EN ISO 4833-1:2013 is a core reference for standardized, reproducible colony count testing using the pour plate technique in food microbiology and environmental monitoring.