Organic acids decontamination

Different organic acids, primarily lactic acid, have been successfully used for decontamination of whole livestock carcasses, and the application of different organic acids used for decontamination has also been tested in the fruit and vegetable industry. Organic acids other than lactic acid that are known to have bactericidal effects are acetic, benzoic, citric, malic, propanoic, sorbic, succinic and tartaric acids (Betts and Everis 2005). The antimicrobial action is due to a reduction in the pH in the bacterial environment, disruption of membrane transport, anion accumulation or a reduction in the internal pH in the cell (Busta et al., 2001). Many fruits contain naturally occurring organic acids. Nevertheless, some strains, for example E. coli 0157, are adapted to an acidic environment. Its survival, in combination with its low infective dose, makes it a health hazard for humans. 

Samelis, J., Sofos, J.N., Kendall, P.A., and Smith, G.C. 2002. Effect of acid adaptation on survival of Escherichia coli 0157 H7 in meat decontamination washing fluids and potential effects of organic acid interventions on the microbial ecology of the meat plant environment. Journal of Food Protection 65 33M0. 

Smulders, F.J. and Greer, G.G. 1998. Integrating microbial decontamination with organic acids in HACCP programmes for muscle foods Prospects and controversies. International Journal of Food Microbiology 44 149-169. 

In Table 3.1 some factors are stipulated that should be considered in the decontamination of meat (European Union, 1996). Spraying with 1.5-2.5% organic acids such as acetic or lactic acid is effectively applied on red meat carcasses (Canadian Food Inspection Agency, 2004). Lactic and acetic acid solutions are commonly used by the red meat slaughtering industry as an antimicrobial spray wash on freshly slaughtered beef carcasses. These spray washes are used in the early steps of beef carcass processing, usually applied to carcasses after hide removal, before and after evisceration, but before chilling (Berry and Cutter, 2000). 

In decontamination of red meat carcasses the use of 1.5-25% of the following organic acids is permitted Acetic acid Lactic acid Citric acid Application/description... 

Table 3.3 Factors That Determine the Selection of Organic Acids in Meat Decontamination...

In carcass decontamination dilute solutions of organic acids (1-3%) normally do not have any effect on the sensory properties of meat. However, it is known that lactic and acetic acid can produce unfavorable sensory changes if applied directly to meat cuts, which may be irreversible. Salts of organic acids are approved for use as food ingredients such as emulsifiers, color and flavor enhancers, and humectants. They are also used to enhance the quality of cooked or cured meat products and to control the pH (Smulders and Greer, 1998). Sodium lactate is approved for use as (1) a flavor enhancer, (2) humectant, and (3) pH control agent (Lemay et al., 2002). 

Feed with formic and propionic acids has been found to reduce Salmonella colonization in broilers (Thomson and Hinton, 1997), whereas decontamination of chicken carcasses with acetic or lactic acid reduced Campylobacter on carcasses or meat (Van Netten et al., 1994 Chaveerach et al., 2002). Organic acids, when added to feeds, should be protected to avoid dissociation in the crop and in the intestine that are known to possess higher pH and to reach far into the GIT, where the targeted bacterial population is situated (Gauthier, 2005). 

Treated carcasses are known to possess pH values ranging from 3.3-5.8 (Kanellos and Burriel, 2005 Mehyar et al., 2005 Del Rfo et al., 2007). The pH may be influenced by different factors, such as (1) the type of organic acid, (2) treatment time, (3) organic acid concentration, and (4) combinations with other decontamination techniques (Del Rfo et al., 2007 Alvarez-Ordonez et al., 2009). 

Smulders, F. 1987. Prospectives for microbial decontamination of meat and poultry by organic acids with special reference to lactic acid. In F.J.M. Smulders (Ed.), Elimination of Pathogenic Organisms from Meat and Poultry, pp. 319-344, London Elsevier Science, Biomedical Division. 

Findings from a study done on acid-adapted Salmonella to lactic acid rinses from artificially inoculated beef muscle slices showed that acid-adapted strains were not any more resistant to acid decontamination than parental strains (Dickson and Kunduru, 1995). In a study done by Steiner and Sauer (2003), the overexpression of the ATP-dependent heli-case RecG was found to increase resistance to weak organic acids in E. coli. This was achieved by reduction of the toxic effects of the organic acids, reduction of the effects of the synthetic uncouplers (CCCP and DNP), and a reduction of the ATPase and cytochrome c inhibitor azide as a result of a decrease in pH or available ATP. In LAB, resistance mechanisms to... 

Safety concerns have intensified with regard to the potential implications of pathogen behavior and the microbial ecology of carcass decontamination with organic acid spray washes of meat. On beef decontaminated with lactic acid increases of nearly 3 logs within five days of storage at 10°C under air or vacuum have been recorded, whereas increases were only 1 log and virtually nonexistent on untreated beef. Meat-packing... 

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