Modified Atmosphere Packaging of Ready Meals and Other Cook-Chill Products

Extending the shelf-life of Ready Meals and Cook-Chill products

MAP modified atmosphere packaging for prepared foods, or ready meals and other cook-chill products, including Casseroles, ready meals containing fish, ready meals containing game-bird, goulash, ready meals containing meat, ready meals containing offal, ready meals containing pasta, ready meals containing poultry, sauces, ready meals containing seafood, soups* and ready meals containing vegetables, etc.

Cook-chill is a catering or food processing system whereby food is hygienically prepared, pasteurized, and rapidly chilled to between 0°C and 3°C. The food is then stored at 0°C to 3°C before being reheated to 70°C for two minutes (or the thermal equivalent) prior to consumption.

Under UK Department of Health (1989) guidelines for cook-chill, the maximum recommended shelf-life for such products is five days. However, these guidelines only refer to cook-chill products intended for the catering market, and the possibility exists for such products to have longer permitted shelf-lives if packed under MAP or cooked under vacuum (sous vide) by food manufacturers for the retail market.

The Advisory Committee for the Microbiological Safety of Foods (1992: ‘Report on Vacuum Packaging and Associated Processes’) has concluded that chilled foods with a shelf-life shorter than 10 days should if kept at chilled temperatures, present a minimal risk of the growth and toxin production by Clostridium botulinum.

The principal spoilage mechanism for ready meals and other cook-chill products is microbial growth, which is primarily due to post-cooking contamination and/or poor temperature control. The pasteurization cooking process should kill vegetative bacterial cells, inactivate degradative enzymes, and also fix the color. However, heat-resistant spores, such as those from Clostridium species and Bacillus species, will survive the cooking process and may germinate if recommended chilled temperatures are not maintained.

The other possible food poisoning hazards can arise from post-cooking contamination as a result of poor hygiene and handling practices and faulty seal integrity. Poor temperature control will exacerbate the problem of microbial growth. Therefore, it is recommended that strict control over temperature, hygiene, and handling be maintained throughout. The use of additional barriers to microbial growth (such as acidification, use of preservatives, and/or reduction in aw), wherever appropriate, is strongly recommended. MAP can significantly extend the shelf-life of ready meals and other cook-chill products. Apart from delaying microbial spoilage, the use of CO2/N2 gas mixtures has also been found to delay
the development of oxidative warmed-over flavor. A gas/product ratio of 2:1 is recommended

General Information for Modified Atmosphere Packaging of Ready Meals and Cook-Chill Products