Microbiological Aspects of Modified-Atmosphere Packaging Technology - A Review

Abstract

Modified-atmosphere packaged (MAP) foods have become increasingly more common in North America, as food manufacturers have attempted to meet consumer demands for fresh, refrigerated foods with extended shelf life. Although much information exists in the general area of MAP technology, research on the microbiological safety of these foods is still lacking. The great vulnerability of MAP foods from a safety standpoint is that with many modified atmospheres containing moderate to high levels of carbon dioxide, the aerobic spoilage organisms which usually warn consumers of spoilage are inhibited, while the growth of pathogens may be allowed or even stimulated. In the past, the major concerns have been the anaerobic pathogens, especially the psychrotrophic, nonproteolytic clostridia. However, because of the emergence of psychrotrophic pathogens such as Listeria monocytogenes, Aeromonas hydrophila, and Yersinia enterocolitica, new safety issues have been raised. This stems mainly from the fact that the extended shelf life of many MAP products may allow extra time for these pathogens to reach dangerously high levels in a food. This review focuses on the effects of MAP on the growth and survival of foodborne pathogens. Considered are the major psychrotrophic pathogens, the mesophiles such as the salmonellae and staphylococci, as well as the microaerophilic Campylobacter jejuni. The use of MAP in various food commodities such as beef, chicken, fish, and sandwiches is also discussed. Examples of various foods currently being packaged under MAP in North America are given, along with the specific atmospheres employed for the various food groups. Major safety concerns that still need to be addressed include the potential for growth and toxin production of Clostridium botulinum type E in MAP fish products, the growth of L. monocytogenes and A. hydrophila under modified atmospheres in various food commodities, and the enhanced survival of anaerobic spores and C. jejuni under certain gas atmospheres. Additional research with MAP foods is needed to ensure the microbiological safety of the numerous MAP products that will be available to the consumer in the next decade and beyond.

Processamento mínimo em goiabas 'Paluma' e 'Pedro Sato': 2. Avaliação química, sensorial e microbiológica

“…Estes mesmos autores relatam que coliformes em meio seletivo representaram uma pequena porção dos contaminantes bacterianos, e que coliformes fecais não foram detectados na maioria das amostras estudadas. Segundo FARBER [7], o CO 2 solú-vel em água e os lipídeos, são os principais responsáveis pelo efeito bacteriostático a microrganismos que podem crescer em produtos minimamente processados. As combinações requeridas de temperatura, concentrações de O 2 e CO 2 variam com o tipo de vegetal, a variedade, a origem e a estação do ano [21].…”

Evaluating the effect of modified atmosphere packaging on cheese characteristics: a review

“…pH reduction, caused by CO 2 atmosphere, was reported in the literature (Farber 1991;Mannheim and Soffer 1996;Koskeli 1998) and was presumed as one of the mechanisms for microbial growth inhibition by CO 2 (King and Nagel 1967;Daniels et al 1985). Mannheim and Soffer (1996), in their study evaluating the shelf life extension of Cottage cheese by MAP (pure CO 2 at 8°C storage), observed a drop in the value.…”

Influence of modified atmosphere packaging and potassium sorbate on microbiological characteristics of sliced bread

“…Because of its insolubility in water, the presence of nitrogen in MAP food can prevent pack collapse that occurs when high concentrations of CO 2 are used ( Ponte et al 1993;Smith and Simpson 1995;Kotsianis et al 2002). The general recommendation for MAP of bakery products has been a mixture of 60% CO 2 :40% N 2 , but specific gas mixtures should be used for each type of product and mixtures have variations from 0 to 100% CO 2 balanced with N 2 (Farber 1991;Suhr and Nielsen 2005).…”