Overview
EN 15785:2009 - "Animal feeding stuffs - Isolation and enumeration of Bifidobacterium spp." (CEN) defines a validated, harmonised method to detect, isolate and enumerate probiotic Bifidobacterium in animal feed matrices (additives, premixtures and feeding stuffs). The standard supports official control and labelling verification by providing general rules for sample preparation, dilution, plating, incubation and colony verification. It excludes mineral feeds (≥40% crude ash).
Key topics and technical requirements
- Scope and sample categories: procedures apply to additives, premixtures and complete feeds; the standard lists typical target loads (given in the document as about 1010 CFU/g for additives, 108 CFU/g for premixtures and 106 CFU/g for feeds/meal/pellets).
- Sampling and sample prep: sampling per relevant product standards or agreed protocols; preparation of initial suspensions and decimal dilutions following EN ISO 6887-1 and ISO 6498 principles.
- Media and selective options: MRS agar is the baseline medium. Variants specified include MRS + TTC (differentiation), AMRS (acidified MRS) and a mupirocin-cysteine selective MRS for situations where bifidobacteria are outnumbered by other lactic bacteria. Exact media formulations and preparation steps are provided.
- Incubation and detection: anaerobic incubation at 37 °C ±1 °C for 36–48 h. Detection limit is defined according to EN ISO 7218.
- Phenotypic verification: colony morphology descriptions and phase-contrast microscopy are used to verify isolates as Bifidobacterium spp. Plate counting and expression of results (CFU per g or kg) are specified.
- Quality and precision: procedures, sterility checks, equipment needs (anaerobic jars/chambers, incubators, blender, 600–1 000× microscope) and interlaboratory precision data are included.
Applications and who uses it
- Quality control laboratories in animal feed and probiotic manufacturers - for routine enumeration and lot release testing.
- Regulatory bodies and official control laboratories - to verify labelling claims of probiotic content.
- Research and product development teams - to assess survival and formulation effects on bifidobacteria in feed matrices.
- Feed ingredient and premix producers - to validate production and storage practices that affect probiotic counts.
Related standards
- EN ISO 6887-1 - preparation of test samples and decimal dilutions
- EN ISO 7218 - general microbiology requirements and detection limits
- ISO 6498 / ISO 6497 - guidance on test sample preparation and sampling (referenced in EN 15785)
EN 15785:2009 is a practical, validated protocol for accurate enumeration of probiotic Bifidobacterium spp. in feeds, helping ensure compliance with labelling and quality requirements for animal feeding stuffs.