Modified Atmospheric Packaging(MAP)is a precise description of this shelf- life extension technique (Bennett 1995). In the UK, MAP mainly involves the use of three gases-carbon dioxide, nitrogen and oxygen although other gases are used elsewhere. Products are packed in various combinations of these three gases depending on the physical and chemical properties of the food

Modified atmosphere packaging(map) is widely used for many food products and is now a commercial and economic reality. MAP is common in markets that have a well established and controlled cold chain and that can sustain a high- priced quality product. However, MAP is a mild preservation method and a major concern is that MAP storage may not provide a sufficient level of safety for the extended storage of fresh chilled food products with regard to pathogenic

Package integrity is an essential requirement for maintaining the high quality of, for example, sterilised foods and modified atmosphere packaged foods. The increasing focus on quality assurance is putting demands on verification of food package integrity. The foremost noticeable package integrity problem is probably leaking seals, particularly with flexible plastic packages which are more prone to mechanical damage than traditional rigid metal packages. A non- destructive leak test device allowing evaluation of every container produced is. therefore, of interest to food manufacturers

Modified atmosphere packaged (MAP )prepared fresh produce provides substrates and environmental conditions conducive to the survival and growth of microorganisms. Minimal processing treatments such as peeling and slicing disrupt surface tissues, expose cytoplasm and provide a potentially richer source of nutrients than intact produce(Brackett 1994; Barry-Ryan and O'Beirne, 1998, 2000). This, combined with high Aw and either close to neutral (vegetables) or low acid (many fruits) tissue pH, facilitate microbial growth (Beuchat, 1996)

Modified atmosphere packaging (MAPmay be defined as the enclosure of food products in gas-barrier materials in which the gaseous environment has been changed'(Young et al., 1988 Because of its substantial shelf-life extending effect, MAP has been one of the most significant and innovative growth areas in retail food packaging. The potential advantages and disadvantages of MAP have been presented by Farber (1991), Parry(1993) and Davies (1995). Whilst there is considerable information available regarding suitable gas mixtures for different food products, there is still a lack of scientific detail regarding many aspects relating to MAP. These include:

During recent years there has been an explosive growth in the market for fresh prepared fruit and vegetable (i.e. produceproducts. The main driving force for this market growth is the increasing consumer demand for fresh, healthy, convenient and additive-free prepared product items. However, fresh prepared produce items are highly perishable and prone to the major spoilage mechanisms of enzymic discoloration, moisture loss and microbial growth. Good manufacturing and handling practices along with the appropriate use of modified atmosphere packaging(mp)are relatively effective at inhibiting

9.1 Introduction Drying is probably the oldest form of preservation Wrapping things that have been dried to protect them from moisture may well have been the earliest form of packaging. Even today a lot of technological development resources are expended to find new ways to package things to keep them dry. Some of the oldest materials used to control moisture are still used today: clay, salt, minerals and plant extracts that have a greater affinity for water than the material being protected. Clay has been used for centuries; moist clay to keep things moist and dried clay to keep things dry. Likewise the importance of salt is legendary

Interactions within a package system refer to the exchange of mass and energy between the packaged food, the packaging material and the external environment. Food-packaging interactions can be defined as an interplay between food, packaging, and the environment, which produces an effect on the food, and/or package (Hotchkiss, 1997). Mass transfer processes in packaging systems are normally referred to as permeation, migration and absorption(fig8.1). Permeation is the process resulting from two basic mechanisms

As we know from the definition, intelligent or smart packaging monitors and gives information about the quality of the packed food. According to Huis in't give Veld (1996) the changes taking place in the fresh food product can be categorised as (i) microbiological growth and metabolism resulting in pH- changes, formation of toxic compounds off-odours, gas and slime formation

6.1 Introduction The modern food industry is called on to deliver seemingly contradictory market demands. On the one hand consumers want improved safety and sensory quality, together with increased nutritional properties, extended shelf-life and convenience in preparation and use. On the other they want food with a traditional, wholesome image, with less processing and fewer additives