Abstract:

The oily food additives are difficult to be exactly diluted using sterilized physiological saline or phosphate buffer solution according to GB 4789 methods to detect the microbial contaminations. And the inappropriately diluted manner affects the result accuracy directly. This research had established a proper dilution method through application of compound surfactants in the pretreatment processions. The emulsifying powers and microbial growth effects of Tween-80 compounded with Span-80 had been studied. The results showed that added compound surfactants of Tween-80 with Span-80 (1:1) in the concentrations from 1% to 5% had no effects on microbial growth. And the oily food additives (oil content >95%) had been relatively stable emulsificated by only 2% of compound surfactants in the dilution system. This research provided convenient and accurate sample pretreatment techniques which were especially useful for oily foods to detect the microbial contaminations.