Effect of Glycine on Production of Staphylococcal Enterotoxin A in Cooked Rice, and Limitation of Its Organoleptic Detection

• Published in: Journal of Home Economics of Japan Vol. 69; no. 12; pp. 799 - 810
• Main Authors: TSUTSUURA, Satomi, HAYASHIDA, Naoko, MURATA, Masatsune
• Format: Journal Article
• Language: Japanese
• Published: The Japan Society of Home Economics 2018
• Subjects: cooked rice; food poisoning; glycine; staphylococcal enterotoxin A (SEA); Staphylococcus aureus; western blot analysis
• ISSN: 0913-5227; 1882-0352
• DOI: 10.11428/jhej.69.799

  The aim of this study was to clarify the effect of glycine on the growth of Staphylococcus aureus and the production of staphylococcal enterotoxin A (SEA) in cooked rice. We inoculated eleven strains of SEA-producing S. aureus at inoculum size of 106 CFU/g into cooked rice to which 0-5% glycine was added, and then quantified the bacterial number and SEA after incubating them at 37℃. The maximal concentrations of SEA were 2.1-40.8 ng/g, 1.9-53.9 ng/g, 0.9-35.0 ng/g, and 0 (not detected) －3.7 ng/g in cooked rice to which 0.5, 1, 2, and 5% glycine was added, respectively. Most strains of S. aureus produced less SEA in cooked rice to which 2 and 5% glycine was added than in the non-added control during the early phase of growth. However, the amount of SEA in contaminated cooked rice with S. aureus will reach a sufficient level to cause food poisoning regardless of the addition or non-addition of glycine, before its growth is perceived organoleptically.