Reduction in peroxide values and monocarbonyls of oxidized methyl oleate by several microbial cultures

Abstract

With oxidized methyl oleate as the substrate, a rapid method for the determination of microbial destruction of peroxides and monocarbonyls has been developed. Staphylococcus aureus showed extensive destruction of peroxides by both cells and supernatant fluid, while Bacillus cereus, Micrococcus cryophilus, Serratia marcescens, and Sarcina lutea had activity only in the cells. Escherichia coli was inactive. Destruction of 2,4-dienals, 2-enals, and n-alkanals followed a similar pattern except that E. coli cells also were active against the monocarbonyl classes. Paper chromatography did not reveal any selective action against specific monocarbonyls within the classes.

Relationship of Microbial Activity to Changes in Lipids of Foods

“…Aspergillus jiavus, for example, destroyed peroxides and produced large increases in monocarbonyls, whereas C. lipolytica decomposed peroxides but showed a decrease in the monocarbonyl content. The experiments of Lilly, Smith & Alford (1970) indicate that the peroxide and monocarbonyl destruction by microorganisms is an enzymic process. There was no activity when the microbial fraction was boiled and the activity was found to be dependent on pH, temperature and enzyme-substrate ratio.…”

Physiological and Metabolic Attributes of Microbial Groups Associated with Foods

“…The oxidation of acetic acid by Acetobacter spp. (Divies & Dupuy, 1969), the breakdown of benzoic acid and its derivatives by moulds or bacteria (Laxa, 1930;Ingram, 1960;Stevenson, 1967), the assimilation of nitrite by yeasts (Wickerham, 1957), the reduction of peroxides by various bacteria (Lilly et al, 1970) and the dissimilation of sorbic acid by certain moulds (Rehm et al, 1963;Marth, 1966) may eventually clear the way for micro-organisms, previously inhibited, to spoil foods preserved by the addition of these preservatives. Another example is the breakdown of phenols by certain bacteria (Kramer & Doetsch, 1950;Ribbons, 1966) which enables the development of microorganisms normally inhibited by the smoking process; in this way contaminants of smoked foods not previously thought to be able to participate may be found in the spoilage association.…”