In New Product Development there are many stages that need to be considered. It is not possible to simply produce a great quality food from the finest ingredients in a home kitchen and up scale to full production without considering issues such as:

• Formulation
• Ingredient supply
• Product processing
• Packaging
• Storage temperatures (chilled/frozen)
• Shelf life
• Nutritional content (fat/salt/sugar)
• Quality

Often many of the above factors are interlinked, such as packaging and shelf-life (for example: modified atmosphere packaging can be used to keep the product fresher for longer). Often one key consideration which is excluded from list is how the product will be cooked or re-heated. The selection of re-heating instructions using appropriate appliances can have a huge impact on the nutritional content and organoleptic quality of the food. Furthermore, the intended mode of reheating needs to be carefully considered during the design stages of the product. For example, a product heated in a microwave will heat in a different manner compared to heating in a conventional oven. The microwave product may need different formulation and packaging to the conventionally heated product. Considering the re-heating of products during the design stages is far simpler than having to re-formulate and re-package a product after full scale production.

Key drivers in New Product Development are health issues, quality and green issues including energy use. The careful consideration of re-heating can have positive benefits for all three. Careful design of the product with the re-heating instructions in mind can lead to shorter heating times, giving less time for nutrient destruction, less energy required during the re-heating process and a better quality product, as overheated areas will be less likely. Re-heating is an area often overlooked, but is a key element in the delivery of safe, high quality foods.

What is re-heating?

A very good question and one that is only answered by an in-depth understanding of the specific food products in question. One simple definition might be that re-heating is the act of warming up a ready cooked or processed food. However, the requirements of re-heating in terms of the temperature required to give both an assurance of food safety and palatability in the food depend very much on the food itself, the storage conditions and any previous processing the food has undergone, together with the packaging used to hold and protect the food.

The target temperature aimed for at the end of the re-heating process depends on whether the food can be classed as safe to eat without further thermal treatment (such as some bakery goods, or canned foods) or whether the food requires reheating to kill any possible food poisoning bacteria that may have re-contaminated or grown on the food prior to the re-heating process. With the former two types of product, reheating is purely a matter of supplying sufficient heat energy to the product to make it palatable and taste sufficiently hot. Therefore the temperature to which the product is re-heated depends on several factors, such as personal taste (some people like their food hotter than others!) and the ability of the food to hold and conduct heat (for example soup is best served hotter than Christmas pudding). This article focuses on foods falling into the latter category, where the re-heating process is a necessary step to safeguard the food from possible food poisoning issues. It is difficult to produce a food where once it has been cooked, cooled and stored there is no doubt that bacterial recontamination or growth has not occurred. For example, almost all retailers require that raw food and food that has been pre-cooked prior to sellingto customers (lasagne for example) achieve sufficient temperature on re-heating to kill any pathogenic (foodpoisoning) bacteria that may have contaminated or grown on the food during the production and chilledstorage (by the retailer or consumer) process. Foods that require chilling to maintain their microbiological