Organic acids Feed preservative effects

Several factors can alter the effective concentration of a preservative in food products or feed (Ricke, 2003). The spectrum of activity of some organic acids, in particular sodium lactate, is relatively narrow or may be specific to a certain group of organisms. This may pose a problem, as other mechanisms may take over after time (Lemay et al., 2002). Sodium benzoate or potassium sorbate are both chemical preservatives, approved for use in a wide range of foodstuffs, but have been shown to have only limited effect on E. coli 0157 H7 (Comes and Beelman, 2002). This observation is augmented by the fact that various microbiota can utilize organic acids as both carbon and energy sources (Van Immerseel et al., 2006). 

Organic acids, such as propionic acid, have been used for more than 30 years to reduce bacterial growth and mould in feedstufifs and thus preserve hygienic quality. In feed legislation they are registered as preservatives, but their positive effects on animal health and performance, if they are added to feed in sufficient amounts, are also well documented. Acids used as feed additives are predominantly compounds that naturally occur in cell metabolism, thus they are natural products with low toxicity (Kirchgessner and Roth, 1988). 

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