ISO/TC 34/SC 9/WG 8 - Preparation of test samples, initial suspension and decimal dilutions

This document specifies rules for the preparation of samples of milk and milk products and their suspensions for microbiological examination when the samples require a different preparation from the general methods specified in ISO 6887-1. This document excludes the preparation of samples for both enumeration and detection test methods where preparation details are specified in the relevant International Standards. This document is intended to be used in conjunction with ISO 6887-1. This document is applicable to: a) milk and liquid milk products; b) dehydrated milk products; c) cheese and cheese products; d) casein and caseinates; e) butter; f) milk-based ice-cream; g) milk-based custard, desserts and sweet cream; h) fermented milks, yogurt, probiotics milk products and sour cream; i) dehydrated milk-based infant foods, with or without probiotics.

ISO 6887-1:2017 defines general rules for the aerobic preparation of the initial suspension and of dilutions for microbiological examinations of products intended for human or animal consumption. ISO 6887-1:2017 is applicable to the general case and other parts apply to specific groups of products as mentioned in the foreword. Some aspects might also be applicable to molecular methods where matrices can be associated with inhibition of the PCR steps and consequently affect the test result. ISO 6887-1:2017 excludes preparation of samples for both enumeration and detection test methods where preparation instructions are detailed in specific International Standards.

ISO 6887-4:2017 specifies rules for the preparation of samples and dilutions for the microbiological examination of specific food products not covered in other parts of ISO 6887, which deal with more general categories. This document covers a wide range of miscellaneous products, but does not include new products brought on to the market after publication. ISO 6887‑1 defines the general rules for the preparation of the initial suspension and dilutions for microbiological examination. ISO 6887-4:2017 excludes preparation of samples for both enumeration and detection test methods when preparation details are specified in the relevant International Standards. ISO 6887-4:2017 is applicable to the following products: - acidic (low pH) products; - hard and dry products; - dehydrated, freeze-dried and other low aw products (including those with inhibitory properties); - flours, whole cereal grains, cereal by-products; - animal feed, cattle cake, kibbles and pet chews; - gelatine (powdered and leaf); - margarines, spreads and non-dairy products with added water; - eggs and egg products; - bakery goods, pastries and cakes; - fresh fruit and vegetables; - fermented products and other products containing viable microorganisms; - alcoholic and non-alcoholic beverages; - alternative protein products.

ISO 6887-2:2017 specifies rules for the preparation of meat and meat product samples and their suspension for microbiological examination when the samples require different preparation from the methods described in ISO 6887‑1. ISO 6887‑1 defines the general rules for the preparation of the initial suspension and dilutions for microbiological examination. ISO 6887-2:2017 excludes preparation of samples for both enumeration and detection test methods where preparation details are specified in the relevant International Standards. ISO 6887-2:2017 is applicable to the following fresh, raw and processed meats, poultry and game and their products: - refrigerated or frozen; - cured or fermented; - minced or comminuted; - meat preparations; - mechanically separated meat; - cooked meats; - dried and smoked meats at various degrees of dehydration; - concentrated meat extracts; - excision and swab samples from carcasses. ISO 6887-2:2017 excludes the sampling of carcasses (see ISO 17604) and preparation of samples from the primary production stage (see ISO 6887‑6).

ISO 6887-3:2017 specifies rules for the preparation of fish and fishery product samples and their suspension for microbiological examination when the samples require a different preparation from the methods described in ISO 6887‑1. ISO 6887‑1 defines the general rules for the preparation of the initial suspension and dilutions for microbiological examination. ISO 6887-3:2017 includes special procedures for sampling raw molluscs, tunicates and echinoderms from primary production areas. NOTE 1 Sampling of raw molluscs, tunicates and echinoderms from primary production areas is included in this document, rather than ISO 13307, which specifies rules for sampling from the terrestrial primary production stage. ISO 6887-3:2017 excludes preparation of samples for both enumeration and detection test methods where preparation details are specified in the relevant International Standards (e.g. ISO/TS 15216‑1 and ISO/TS 15216‑2 for determination of hepatitis A virus and norovirus in food using real-time RT-PCR). ISO 6887-3:2017 is intended to be used in conjunction with ISO 6887‑1. It is applicable to the following raw, processed or frozen fish and shellfish and their products (see Annex A for classification of major taxa): a) Raw fishery products, molluscs, tunicates and echinoderms including: - whole fish or fillets, with or without skin and heads, and gutted; - crustaceans, whole or shelled; - cephalopods; - bivalve molluscs; - gastropods; - tunicates and echinoderms. b) Processed products including: - smoked fish, whole or prepared fillets, with or without skin; - cooked or partially cooked, whole or shelled crustaceans, molluscs, tunicates and echinoderms; - cooked or partially cooked fish and fish-based multi-component products. c) Raw or cooked frozen fish, crustaceans, molluscs and others, in blocks or otherwise, including: - fish, fish fillets and pieces; - whole and shelled crustacean (e.g. flaked crab, prawns), molluscs, tunicates and echinoderms. NOTE 2 The purpose of examinations performed on these samples can be either hygiene testing or quality control. However, the sampling techniques described in this document relate mainly to hygiene testing (on muscle tissues).