22 - Fresh meat spoilage and modified atmosphere packaging (MAP)

Abstract

Meat microbiology began to attract scientific attention almost immediately following the founding of bacteriology as a science in its own right. This attention started to increase when large amounts of meat were being shipped long distances and continued in the 1950s with the growth of supermarkets. To meet this need, a “new” concept (packaging system) had to be developed that had these attributes: (i) extension of shelf-life by suppressing microbial growth; (ii) protection of meat from external microbial contamination; and (iii) selection of little known microbial associations. This packaging system called Modified-Atmosphere Packaging (MAP) can indeed extend the shelf-life and sustain the visual appearance of refrigerated meats with almost any combination of carbon dioxide, nitrogen, and oxygen. Much work has been focused on the prevention of spoilage of meat and meat products by organisms, such as pseudomonads. However, concerns have been expressed by regulatory authorities, food industry groups, and others that the practice may lead to unpredictable hazards. Indeed, despite the increasing commercial interest in the use of MAP to extend the shelf-life of perishable products such as meat and poultry, the concern about the potential growth of pathogenic bacteria that could survive and grow even at refrigeration temperatures, remains a limiting factor to further expansion of the method. It is evident in this chapter that only a few studies have examined the effect of MAP on the growth/survival of foodborne pathogens, particularly psychrotrophic strains. The chapter discusses the importance of studying microbial interactions and physicochemical attributes during storage under MAP conditions to understand the mechanisms of spoilage and better evaluate the potential risks of this technology. This will facilitate the application of such technology with long-term economic benefits.