Identification and contamination level of osmophilic yeast in domestic and imported honey

Abstract

ObjectiveOsmophilic yeast in honey at home and abroad was identified ， and the contamination levels of honey was understood.MethodsA total of 916 batches of domestic and imported honey were selected， and osmophilic yeast was counted according to GB 14963—2011 “National Standard Food Safety -Honey” and GB 4789.2—2022 “National Standard Food Safety -Determination of the total number of colonies for microbial Inspection”， and the detection rate of osmophilic yeast was calculated. The species of isolated strains were identyfied by 26S rDNA PCR. The ability of some yeast strains to tolerate high sugar and produce alcohol were tested by absorbance and potassium bichromate colorimetry.ResultsIn 916 batches of honey， 36 batches of osmophilic yeast were detected， the detection rate was 3.93%， and the over-standard rate was 3.49%. Among 786 batches of domestic honey， 33 batches of osmophilic yeast were detected， the detection rate was 4.20%， with osmophilic yeast from 2.5×102 to 7×104 CFU/g. Three osmophilic yeasts were detected in 130 batches of imported honey， the detection rate was 2.31%， with osmophilic yeasts from 1×101 to 7×101 CFU/g. Five osmophilic yeast strains were isolated， one was Moesziomyces aphidis/Pseudozyma sp.， and three were Zygosaccharomyces mellis. One was Candida magnoliae， and all of the tested strains were well tolerant to high glucose concentrations and had some capacity to produce alcohol.ConclusionHoney may be contaminated by osmophilic yeast， so it is necessary to strengthen its control and management. Honey can be used as a source for screening osmolal-resistant strains， and the selection of osmophilic yeast is helpful to the development of honey food fermentation industry and the research and development of excellent products.

Keywords

• honey
• osmophilic yeast
• strain identification
• high glucose tolerance
• contaminate