Formation of Benzoic Acid in Cheese

Abstract

Benzoic acid, one of the synthetic preservatives, was detected in cheese as a natural product, and identified using gas chromatograph and a combined gas chromatograph-mass spectrometer. A method for measuring benzoic acid content of cheese was investigated. This method is based on ether extract, cleaning up with acid-treated Florisil column chromatography and gas chromatographic analysis. The recovery was 96.4%.
The amounts of benzoic acid in 25 samples of cheese were determined. The values ranged from 1.6 to 40.6μg/g of cheese. Not so significant differences were found in benzoic acid content between cheese varieties, domestic and imported. From the viewpoint of food hygiene, these amounts might be acceptable, but benzoic acid produced in cheese may contribute to the antimicrobial activity of cheese.
The precursors of benzoic acid in cheese were investigated by manufacturing the yeastripened cheese, to which hippuric acid, phenylalanine, tyrosine, phenylalanine-U-¹⁴C, or tyrosine-U-¹⁴C was added. It was suggested that the greater amount of benzoic acid in cheese might be produced from hippuric acid in milk by bacteria in the early stage of ripening and a small part might be derived from phenylalanine. Tyrosine was not converted into benzoic acid.