Evaluation of CHROMagar^TM Orientation with Egg-Yolk for Bacterial Cleanliness Test of Food Manufacturing Environment

Abstract

Culture on CHROMagar^TM Orientation medium supplemented with egg yolk emulsion (2.5% EY-CHROM) for 24 hr at 35℃ was comparable to the standard plate count for total bacteria counts, and the medium distinguished Staphylococcus aureus, Escherichia coli and coliforms from other bacteria. For culture of fungi and yeast on 2.5% EY-CHROM, incubation at 25℃ was suitable. It was difficult to test bacteria including S. aureus, E. coli and coliforms, fungi and yeast on a single culture medium under the same culture conditions. However, It claims to facilitate and expedite the differentiation of some bacteria and total bacteria counts on the basis of different contrasted colony colors and hallo produced by chromogenic substrates and egg-yolk.