Method optimization for quantitative determination of the food preservative nisin in dry preparations by bioanalysis with the test culture Heyndrickxia coagulans
Authors:
Lyudmila P. Minaeva, Alexander S. Skorodumov, Tatiana V. Chikhalina, Daria S. Martynova, Maria A. Staronenkova
Abstract:
Nisin, produced by Lactococcus lactis, is currently the only bacteriocin permitted and widely used as a food preservative (E234). To control commercial products present on the Russian market, it is important to develop a standardized method for the quantitative determination of nisin, taking into account modern international requirements. Bioassay based on well diffusion in agar is the most widely used method for determining nisin, characterized by sensitivity, simplicity and cost-effectiveness. The purpose of the study is to optimize the bioassay technique for quantitative determination of nisin A in dry commercial preparations and to test it on experimental samples. The agar diffusion technique was optimized with the Heyndrickxia coagulans test culture using the following parameters: bacterial load, structural model of nutrient agar, sensitivity, and analysis time. As a result, an analysis algorithm was substantiated that ensures high sensitivity, accuracy, and reproducibility of results in the range from 0.5 to 10 IU/ml; the total analysis time was reduced to 24 hours, which allows the method to be used also in routine studies in the technological process. The method was tested on samples of commercial nisin preparations from various manufacturers, stored for a long time at temperatures from –18 to –20 °C. It was shown that nisin activity can be preserved in commercial preparations at a level of 90–100%, including in Russian-made samples with a shelf life of 20 years. Testing the stability of nisin during heat treatment showed that in all the studied samples nisin retained activity in 0.02 N hydrochloric acid solutions (100 ± 9.7)% and was completely inactivated at pH = 11. The optimized bioassay algorithm with the test culture of H. coagulans (strain B-15356) can be used for the quantitative determination of nisin A; the method has been included in the draft of the new edition of the national standard.
Keywords:
food preservative nisin; bacteriocin; bioassay; agar diffusion; quantitative determination of nisin; Heyndrickxia coagulans
For citation:
Minaeva L.P., Skorodumov A.S., Chikhalina T.V., Martynova D.S., Staronenkova M.A. Method optimization for quantitative determination of the food preservative nisin in dry preparations by bioanalysis with the test culture Heyndrickxia coagulans. Индустрия питания|Food Industry. 2025. Vol. 10, No. 3. Pp. 5–19. DOI: 10.29141/2500-1922-2025-10-3-1. EDN: RXUMXI.
