Background and Objective: Benzoate and sorbate are utilized to prevent the growth of microorganisms and to extend the shelf life of most food products. However, according to national hygienic regulations, the use of these two preservatives in kefir is not permitted. In this study, the concentration of these preservatives in kefir was determined using high-performance liquid chromatography. Additionally, due to the importance of this issue and compliance with national regulations—which specify a maximum ethanol limit of 0.5% in kefir—the ethanol content of this product was also determined using the gas chromatography method.
Materials and Methods: In this descriptive-cross-sectional study, 88 samples of industrially produced kefir from different brands were randomly collected from various regions of Iran and sent to the laboratory at 4 °C. Statistical analysis of the data was performed using SPSS software, and one-way ANOVA was applied to compare the mean values. In all tests, a significance level of 0.05 was considered.
Results: Sorbate was not detected in any of the samples, while benzoate was observed in only 11 samples, with an average concentration of 0.6763 mg/L. The average concentration of ethanol was 0.2997%, and in 10 samples, the ethanol content exceeded 0.5%, which is in violation of national regulations.
Conclusion: The presence of trace amounts of sorbate in the product may be attributed to the activity of lactic acid bacteria. The increase in alcohol percentage could also be due to insufficient control over the fermentation process during production. To improve nutritional quality and safeguard consumer health, it is recommended that limits be established for preservatives in this product.
