Complying with Microbiological Criteria

By Phil Voysey - 21 July 2014

The production of safe foods is a priority for all manufacturers. The adoption of systems such as Good Manufacturing Practices (GMP) and Hazard Analysis and Critical Control Point (HACCP) is key to achieving this. One way to verify that these control systems are working correctly is to carry out microbiological testing of the foods being produced. The results of the testing can then be compared to pre–agreed levels (criteria), which will determine if all is well. These criteria can be self–imposed ('microbiological guidelines'), or arrived at by agreement between seller and buyer ('microbiological specifications'); or set in law ('microbiological standards'). Advice on how to set these microbiological criteria is given in Campden BRI Guideline 52.

As far as microbiological standards in the EU are concerned, 'EC Regulation 2073/2005 on Microbiological Criteria for Foodstuffs' is the most important document. This Regulation sets microbiological criteria defining the acceptability of the process used to make the foodstuff, and it also lists food safety criteria, which set a limit above which a foodstuff should be considered "unacceptably contaminated" with the microorganism.

The Regulation does not set microbiological criteria for all food types. It focuses on those where microbiological issues have been experienced in the past. For example, Listeria monocytogenes in ready–to–eat foods, Salmonella in meats and dairy foods; Cronobacter in dried infant formulae, and Shiga toxin–producing E. coli (STEC) in 'sprouts' are all covered.

The Regulation harmonises microbiological criteria across the EU Member States. One of the important things it does not do, however, is specify minimum requirements for testing (except for carcases, some meats and 'sprouts'). It also does not specifically require Food Business Operators (FBOs) to carry out routine microbiological testing or operate a positive release system. However, FBOs do need to show that process hygiene criteria and food safety criteria are met throughout the shelf life of the products, which may involve carrying out durability or challenge test studies. Campden BRI Guidelines 46 and 63 illustrate how these studies can be carried out.

One of the more difficult areas (as far as interpretation is concerned) is to determine if a foodstuff is compliant with criteria for L. monocytogenes in ready–to–eat foods. Broadly speaking, if it can be shown that L. monocytogenes cannot grow to levels above 100 cfu/g during the shelf life of the food, a level of up to 100 cfu/g L. monocytogenes is permitted in the foodstuff. If this cannot (or has not) be(en) shown, then the criterion 'Not Detected in 25g' is applicable. We were involved in drawing up Chilled Foods Association (CFA) / British Retail Consortium (BRC) / Food Standards Agency (FSA) guidance on this.

For EC Regulation 2073/2005, breaching the criteria is not in itself an offence; however, not taking action specified in the Regulation is. If this should happen, or if other microbiological criteria are not met, we are here to help you.

In addition to setting appropriate microbiological criteria for products, factory environment, and process intermediates, we can assist you with advice relating to what to do if criteria are not met. Also, we can help you set an appropriate shelf life for your product and give advice on how the shelf life can be extended if necessary. We are members of both European and ISO groups that establish methods used for challenge testing and can design specific microbiological shelf life evaluation protocols for any product type.

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