🦠 Feedingstuffs — microbiological requirements and tests: presence of anaerobic spore-forming bacilli and Clostridium perfringens, count of fungi (yeasts and moulds), PN-R-64791

Microbiology PN-R-64791

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card, in full (our translation): "Requirements and the range of microbiological tests are given for all kinds of feedingstuffs (excluding the requirements for feed meals of animal origin). Seven terms relating to the subject of the standard have been introduced. The method of sampling and sample preparation is described. Requirements, tests and their detailed description as well as the method of reading and interpreting the results are given. The standard contains 4 annexes, 2 tables, 2 formulae for calculating the number of microorganisms in the feed sample tested" (on the card without a full stop at the end). The card does not name the microorganisms or the media; which tests of this standard the laboratories perform we know only from the accreditation scopes. We did not have the text of the standard (17 pages).

STATUS (state of the cards on 30 September 2026). The card of PN-R-64791:1994 (Polish version) has no "Withdrawn" header — the standard is CURRENT: published 30-12-1994, 17 pages, price group J, Food, Agriculture and Forestry Sector, KT 40 for Feedingstuffs, ICS 07.100.30 and 65.120; a national standard, without an "Introduces" field; "Replaces: PN-R-64791:1976 - Polish version, PN-R-64799:1975 - Polish version". The PKN search for "PN-R-64791" (30 September 2026) shows two items: this standard and PN-R-64791:1976 "Pasze sypkie — Wymagania i badania mikrobiologiczne z zakresu obecności drobnoustrojów czynnych i grzybów toksynotwórczych" (Loose feedingstuffs — Microbiological requirements and tests for the presence of active microorganisms and toxinogenic fungi) with the label "Withdrawn and replaced by PN-R-64791:1994" (label from the list of results; we did not read the card of the 1976 edition).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation-scope database, data loaded up to 17 September 2026, read on 30 September 2026). All notations of number 64791: 16 records at 10 laboratories; in the current PCA documents the number appears 14 times — at AB 819 one cell of reference documents covers two tests (anaerobic spore-forming bacteria and Clostridium perfringens), which the copy splits into separate records. Notations: with the year 1994 — 9 laboratories (AB 606 with a space: "PN-R-64791: 1994"), including those with clauses: "p. 3.3.4.1" (AB 485, AB 1009) and "pkt 3.3.4.1" (AB 924) for anaerobic spore-forming bacilli or bacteria, "pkt 3.3.4.1" for Clostridium perfringens (AB 606) and "p. 3.3.7" for fungi (AB 485, AB 510); without a year — AB 400. The "Laboratories" tab looks for notations that BEGIN with "PN-R-64791" and will show all 10 laboratories — checked with the tab's query on the production server labcoda.pl on 30 September 2026: 10. Current scopes on the PCA website (read on 30 September 2026, issues from 22.12.2025 to 16.09.2026): all entries are in the issues in force and none is suspended.

TESTS AND MATERIALS. Presence of anaerobic spore-forming bacilli (bacteria) — 7 laboratories (AB 400, AB 429, AB 465, AB 485, AB 819, AB 924, AB 1009), by a culture method with biochemical confirmation (AB 924 — without mention of confirmation), at AB 429 and AB 1009 also microscopic. Presence of Clostridium perfringens — 4 laboratories (AB 400, AB 465, AB 606, AB 819), by a culture method with biochemical confirmation; AB 606 cites PN-EN ISO 7937:2005 alongside. Count of fungi or of yeasts and moulds — 3 laboratories (AB 485, AB 510, AB 1738), by the pour plate method. Materials: feedingstuffs — all (at AB 510 "feedingstuffs and pet food"); AB 400 has the Clostridium perfringens entry for "food, feedingstuffs and meals" (flexible scope), and AB 819 — entries for meat and meat products, fruit and vegetable products, herbs and spices and food concentrates, i.e. outside the subject of the standard described on the card. The entries have no numerical ranges.

ALONGSIDE THIS STANDARD. The same determinations in feedingstuffs according to other documents: yeasts and moulds according to PN-ISO 21527-2 (10 laboratories) and PN-ISO 21527-1 (7) as well as the older PN-ISO 7954 (3); the count of Clostridium perfringens according to PN-EN ISO 15213-2 (6 laboratories) and PN-EN ISO 7937 (AB 606, AB 1738), and the count of sulfite-reducing Clostridium spp. according to PN-EN ISO 15213-1 (AB 313, AB 1415). PN-ISO 21527-1 and 21527-2, PN-EN ISO 7937 and PN-EN ISO 15213-2 have separate Knowledge Base entries. In the scopes of feed laboratories this standard also stands next to, among others, Salmonella according to PN-EN ISO 6579-1, aerobic microorganisms according to PN-EN ISO 4833-1 and Enterobacteriaceae according to PN-EN ISO 21528-2 (separate entries).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — which part of the standard: the standard covers several tests, and the accreditation scope and the report should indicate which — five laboratories give the clause (3.3.4.1 or 3.3.7), the others cite the standard as a whole; the same clause 3.3.4.1 appears once for anaerobic spore-forming bacilli and once for Clostridium perfringens. Second — presence versus count: the tests of this standard in the scopes are mostly qualitative ("presence"), while Clostridium perfringens is determined quantitatively in other documents (PN-EN ISO 15213-2, PN-EN ISO 7937) — the results are not interchangeable. Third — materials: the standard concerns feedingstuffs and excludes the requirements for feed meals of animal origin; applying it to food (AB 819, AB 400) or meals (AB 400) goes beyond the scope described on the card. Fourth — age: this is a national standard of 1994; for yeasts and moulds and for Clostridium perfringens there are international standards used by many laboratories — when comparing results, check which method they were obtained by.

WHAT WE DO NOT GIVE. We did not have the text of the standard — PKN sells it (17 pages). We do not give the seven terms, the method of sampling and sample preparation, the microbiological requirements for feedingstuffs, the media, the incubation conditions, the way of confirmation, the reading and interpretation of results or the formulae of this standard; we know the clause numbers 3.3.4.1 and 3.3.7 only from the accreditation scopes.

Method principle

According to the PKN card, the standard gives microbiological requirements for feedingstuffs and a description of the tests, sampling and sample preparation, reading and interpretation of results, with two formulae for calculating the number of microorganisms. In accreditation scopes it is used for detecting anaerobic spore-forming bacilli and Clostridium perfringens by a culture method with biochemical (also microscopic) confirmation and for counting fungi by the pour plate method. We DO NOT GIVE the media, incubation conditions or criteria — we did not have the text of the standard.

Applications

• Feedingstuffs and pet food — presence of anaerobic spore-forming bacilli and Clostridium perfringens, count of fungi — in the scopes of 10 laboratories
• Food (meat and meat products, fruit and vegetable products, herbs and spices, concentrates) — AB 819; food, feedingstuffs and meals — AB 400 (flexible scope)

Key parameters

Standard

Standard number

PN-R-64791:1994 (wersja polska)

Title (PL)

Pasze — Wymagania i badania mikrobiologiczne

Title (EN)

Feedingstuffs — Microbiological requirements and tests

Step-by-step procedure

1. Status and part of the standard

   PKN card: PN-R-64791:1994 current (state of the card on 30 September 2026); indicate the test (e.g. clause 3.3.4.1 or 3.3.7 — numbering according to the accreditation scopes).

2. Sample

   Sampling and preparation according to the standard; we DO NOT GIVE the details.

3. Test

   Anaerobic culture with confirmation (spore-forming bacilli, Clostridium perfringens) or pour plate (fungi); we DO NOT GIVE the media and incubation.

4. Result

   Presence or number of microorganisms in the feed (formulae of the standard — we DO NOT GIVE them) and assessment against the requirements of the standard.

Required equipment and apparatus

Health and safety (OHS)

• Work with cultures of anaerobic bacteria, including Clostridium perfringens, and of fungi — biosafety rules of a microbiological laboratory
• TECHNICAL NOTE: the standard concerns feedingstuffs; results for food and animal meals go beyond its scope as described on the card

Frequently asked questions