Microbiology testing is critical to guarantee food safety and quality. Laboratories performing these tests are required to deliver accurate and reliable results, according to regulatory requirements. Many tests and procedures depend upon culture media being capable of providing consistent and reproducible results. The International Standard ISO 11133 for the preparation, production, storage and performance testing of culture media has been published in 2014 and superseded all previous ISO publications and information on culture media. It’s a mandatory standard for all accredited laboratories that perform microbiological testing of food, animal feed or water using culture media. It defined terms related to quality assurance of culture media and specifies the requirements for the preparation and performance testing of culture media intended for the microbiological analysis of food for human consumption, animal feed, and samples from the manufacturing environment of such products, as well as of all kinds of water intended for consumption or used in food production. Amendment 1 (published in 2018) provides corrections and explanations whilst Amendment 2 (published in 2020) describes the performance testing of confirmation media and reagents.

EN ISO 11133:2014 applies to producers such as commercial bodies producing and/or distributing ready-to-use or semi-finished reconstituted or dehydrated media, non-commercial bodies supplying media to third parties, and microbiological laboratories preparing culture media for their own use.  An ever-increasing number of laboratories source their culture media from suppliers to simplify their workflows and ensure high quality and batch-to-batch consistency of the media they use. This standard takes account of this development by stipulating requirements not only for laboratories that prepare their media in-house but also for manufacturers. With a clear line drawn between the quality assurance responsibilities of users and suppliers, lab managers can now reliably assess which duties and responsibilities no longer apply when they decide to procure culture media. For laboratories that produce their own culture media, two guiding principles are described in this regulation: media preparation and performance testing. Step-by-step instructions, complemented by flow charts, are provided. The standard contains comprehensive tables for the specifications for most culture media, not only for food but now for water microbiology as well.