Changes in Revised ISO 16140

The revised version of the standard ISO 16140 was published in June 2016 as ISO 16140 Part 2, Protocol for the validation of alternative (proprietary) methods against a reference method. This standard is describing the validation of alternative (proprietary) methods compared to a reference method, in the field of microbiology of the food chain. This field is covering the whole chain of food production, from primary production, feed, environment of food processing and handling, storage to end-products. ISO 16140:2003 has been used successfully over the years resulting in more than 100 validated alternative methods that are commonly used by routine testing laboratories. This standard is a common European and International Standard, developed in the framework of CEN (European Committee for standardization) and ISO (International Organization for Standardization) cooperation agreement and it is referenced in European legislation (Commission regulation No. 2073/2005 on microbiological criteria for foodstuffs) as the procedure to validate alternative methods.

The revision of this standard was conducted under the responsibility of Subcommittee ISO technical committee 34/Subcommittee 9 (ISO/TC 34/SC 9), Food Products—Microbiology, and by its Working Group WG 3, Method validation, in cooperation with CEN/TC 275/WG 6, Microbiology of the food chain, to deliver a common standard. WG 3 has not only been responsible for drafting the new ISO 16140-2, but is also drafting other standards that are relevant for validation and verification of methods in microbiology of the food chain.

Why a Standard for Validation of Alternative Methods?

Testing of food for the presence or level of pathogenic microorganisms and hygiene indicators (mostly bacteria, but also yeasts and molds, viruses, and parasites) is crucial for ensuring food safety. Food producers are testing their products based on legal requirements, client specifications and/or as a way to control/check their production process. There is a strong need for analytical methods that will give a result in a very short time but also whose performances are assessed. The standardized methods developed by ISO/TC 34/SC 9 and CEN/TC 275/WG 6 are mainly based on culturing techniques that might take a long time before providing the end result of the test method. This is (partly) due to the fact that the standards cannot use proprietary components in their methods and, in general, prefer methodologies that can culture the target organism so further typing can be done, e.g. for traceability. This is why the methods are regarded as reference methods. In practice, many alternative methods are developed on a commercial (proprietary) basis and are widely used for several reasons. These reasons are, for example, the time to provide the result, easiness of use, and total cost per sample, including human resources. However, it is not known whether the alternative method will give similar results to the reference method. This issue was already noticed in the early 1990s. This lead to a EU funded project, named MicroVal, which started in 1993 and was the basis for the publication of the first version of ISO 16140, which was developed under CEN lead.

Most Important Changes

ISO 16140-2:2016 is the successor of ISO 16140:2003 and the work for the revision started in 2006 as the existing standard lacked, amongst others, objective criteria to validate the methods as fit for purpose.

The principle for both versions is still the same; a protocol describing the validation of qualitative methods and quantitative methods, which require different performance parameters. Both types of studies consist of a method comparison study, carried out in one “expert” laboratory, and an inter-laboratory study led by this expert laboratory. Performance parameters are selected, each with a definition, an experimental design, calculations, and interpretation. The details for conducting the studies and the interpretation of the results have been substantially changed for certain aspects.