Abstract:

reference material of Staphylococcus aureus was prepared by freeze-drying Staphylococcus aureus cells in the
presence of a composite cryoprotectant. The efficacy of the cryoprotectant was verified by comparing the numbers of viable
bacterial cells before and after the freeze-drying, and the homogeneity and stability of the standard substance were studied.
The results showed that the composite protective agent could protect 51.74% of the viable bacterial cells. The homogeneity
and stability after six months of storage of the reference material of Staphylococcus aureus were good. The reference
material can be used for quality control in food testing laboratories and evaluation of food test results.

Key words: Staphylococcus aureus, freeze-drying, protectant, reference material