Spoilage microflora

Identification of Spoilage Microflora Table I lists the bacteria recovered from decomposed skipjack tuna after incubation for 24 h at 38°C. Eighteen of the 134 bacteria isolated were histamine formers, and these strains consisted of obligate and facultative anaerobes. 

Radin, D., Niebuhr, S.E., and Dickson, J.S. 2006. Impact of the population of spoilage microflora on the growth of Listeria monocytogenes on frankfurters. Journal of Food Protection 69 679-681. 

Lakshmanan, R. and Dalgaard, P. 2004. Effects of high-pressure processing on Listeria monocytogenes, spoilage microflora and multiple compound quality indices in chilled cold-smoked salmon. Journal of Applied Microbiology 96 398 08. 

Tahiri et al. (2006) evaluated the effect of DHP technology to inactivate pathogenic and spoilage microflora in orange juice. The inactivation efficacy of DHP depended on the pressure applied and the number of passes. 

Paekaging material has a dual role and aets both to eontain the produet and to prevent the entry of microot nisms or moisture wMeh may resrrlt in spoilage, and it is therefore important that the sotrrce of contamination is not the packaging itself. The microflora of packaging materials is dependent upon both its eomposition and storage eonditions. This, and a consideration of the type of pharmaeeutioal product to be packed, determine whether a sterilization treatment is required. 

The types of spoilage caused by bacteria in fruits and vegetables are diverse they include sensory changes, degradation of compounds, and formation of new substances such as acids, volatile compounds, and polymers. For example, the bacteria produce a set of enzymes such as pectinases, cellulases, proteases, and others that causes maceration and softening of tissue. Off-flavor development is common in contaminated tissues, caused by volatile compounds produced by microflora (Jay 1992). 

Okuzumi et al. (1990) investigated the relationship between microflora on horse mackerel (Trachurus japonicus) and the dominant spoilage bacteria. The results of their study showed that Pseudomonas I/II, Pseudomonas III/IV-NH, Vibrio, and Photobacterium were dominant when high levels of putrescine, cadaverine, and histamine were detected. 

The existence of potentiators could dramatically influence the threshold toxic dose for histamine in foods. Since different fish might be expected to vary in the type and amount of the various potentiators, the threshold toxic dose for histamine would be expected to vary from fish to fish also. The differences in type and amount of the potentiators would be predicted from expected differences in the types of microflora, the metabolic capabilities of the microflora, and conditions of spoilage. Even greater differences would be expected in the comparisons of different species of fish or in comparisons of fish and cheese. Consequently, although the health hazard associated with ingestion of tuna containing 50 mg histamine per 100 g is established, the hazard associated with 50 mg histamine/100 g in other fish and cheese remains to be determined. 

Fernandez A, Picouet P, Lloret E (2010) Reduction of the spoilage-related microflora in absorbent pads by silver nanotechnology during modified atmosphere packaging of beef meat. J Eood Prot 73(12) 2263-2269... 

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