Chemical Antimicrobials

The chemical agents in antimicrobial packaging can be incorporated into the packaging material or inserted into the headspace atmosphere by sachets or labels or closures. The most common chemical antimicrobials used by researchers are the various organic acids. The organic acids, including fatty acids, are naturally existing chemicals and widely used as chemical antimicrobial agents because their efficacy is generally well understood and cost effective (Han, 2005). Sorbic acid, p-aminobenzoic acid, lactic acid, and acetic acid have a long history and are generally recognized as safe (GRAS) food preservatives (Burt, 2004). LDPE (low-density polyethylene) is a polyolefin group of synthetic plastic packaging material that has been commonly used in antimicrobial packaging studies (Singh et al., 2011). Because of the yeast and mold spoilage in cheese and most dairy products, most of the studies in this area are related to the use of organic acids having antifungal property.

According to Weng and Hotchkiss (1993), anhydrides are more compatible with LDPE than their corresponding free acids or salts, due to the lower polarity and higher molecular weight. LDPE films incorporated with 0.5% to 2% benzoic anhydride exhibited antimycotic activity when in contact with cheese and delayed the mold growth on cheese, whereas incorporation of free acids or salts of antimycotic food additives, including propionic acid, benzoic acid, or sorbic acid, into LDPE films failed to inhibit mold growth when the films contacted inoculated media. Similarly, Dobias et al. (2000) reported that LDPE film with incorporated benzoic anhydride can provide significant inhibition of mold growth on the surface of vacuum-packaged cheese. Weng and Hotchkiss (1992) reported that LDPE film containing 1000 mg/kg imazalil (a fungicide) inhibited the growth of Penicillium sp. and Aspergillus toxicarius on cheddar cheese.

Muriel-Galet et al. (2012) showed the inhibitory effect of ethylene vinyl alcohol (EVOH) copolymers containing the lauramide arginine ethyl ester (LAE)—a novel antimicrobial that has been approved by the US Food and Drug Administration (FDA) as GRAS for certain food applications (Saini et al., 2013) by applying them to an infant formula milk inoculated with Listeria monocytogenes and Salmonella enterica. This study showed that infant formula milk stored with the active film had a significant inhibitory effect against both bacteria tested.

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