Considerations for establishing safety-based consume-by date labels for refrigerated ready-to-eat foods

Abstract

The National Advisory Committee on Microbiological Criteria for Foods (NACMCF, or the Committee) was asked to provide advice on the requisite scientific parameters for establishing safety-based use-by dates for refrigerated ready-to-eat (RTE) foods to help reduce the incidence of foodborne illness. To address this request, the Committee reviewed the history of the use of date labels, conducted a hazard analysis of refrigerated RTE foods, provided examples of how safety-based "use-by" date labels (SBDLs) can be formatted and applied, and answered the specific questions posed to the Committee. The Committee determined that if the SBDL concept is pursued, Listeria monocytogenes is the appropriate target organism for refrigerated RTE foods that support its growth. It is important to note that an SBDL will not prevent illness if the food is heavily contaminated, held at high temperatures, or otherwise abused. Given the morbidity and high mortality of L. monocytogenes infection and the association of L. monocytogenes with refrigerated foods, the Committee believes the use of an appropriate SBDL, developed according to the scientific criteria defined herein, could have a beneficial public health impact. Improved epidemiological links between listeriosis and the implicated food could further support this belief. The application of an SBDL for products that support rapid growth of L. monocytogenes at the consumer and food handler level, e.g., "use within x days" of opening/purchase, may have a positive impact on public health if combined with an effective educational program for temperature control at the consumer level. Research is needed to determine consumers' knowledge, attitudes, and practices in relation to SBDLs (refrigeration times and temperatures) and effective formats for presenting the information to maximize the benefits of such labeling. It is necessary to demonstrate that behavioral changes can occur by application of an SBDL. However, application of a specific SBDL (month/day/year) at the manufacturer's level is a concept that has many practical limitations. The magnitude in number, diversity, and complexity of products that exist in the marketplace make practical implementation on a large scale of the food safety objective (FSO)-based SBDL difficult. Accurate information on initial levels and growth rates of L. monocytogenes for many formulations are lacking, and an FSO tied to a public health goal has yet to be established. Scientific parameters identified as important by the Committee include the following: A. The pathogen of concern must be able to grow at refrigerated temperature in the food in question to a level that will be likely to cause illness in the host. B. Scientific evidence that an SBDL will reduce the risk of foodborne illness for that food must be available. C. Identification of safety-based end points is necessary for establishing an SBDL. D. Determination of temperature to use for establishment of an SBDL. The Committee determined that the following items need to be considered in the establishment of SBDLs: • Strain differences • Food matrices • Competing microflora and packaging • Production, distribution, and handling practices • Consumer susceptibility • Initial level • Growth kinetics Verification and validation data necessary to demonstrate the effectiveness of an SBDL will differ depending on where the SBDL is applied. For example, at retail, a validated safe harbor may be used for an SBDL and verification could consist of assuring that the date is clearly visible, legible, and correctly applied. For manufacturers, use of an appropriate safe harbor value based on the literature, regulatory or industry guidelines, or other authoritative source or generation of scientific data using modeling programs or laboratory experiments could be used for validation. The Committee developed guidance for conducting validation studies. The Committee's hazard analysis led to the conclusion that the duration of refrigerated storage is not a major factor in foodborne illness caused by Yersinia enterocolitica, Bacillus cereus, or psychrotrophic Clostridium botulinum. Therefore, the Committee believes that an SBDL to limit the potential for growth of L. monocytogenes would have little or no impact on diseases related to these pathogens. Educational efforts that focus on SBDLs should be combined with an educational effort that focuses on the importance of refrigeration temperature control. As consumers and food handlers increasingly appreciate the importance of adequate refrigeration, this should lead to a reduction in foodborne illness due to pathogen growth.