ENRICHMENT OF MILK WITH MAGNESIUM PROVIDES NOVEL MEAN TO IMPROVE DAIRY PRODUCTS QUALITY AND SAFETY

Microbial damages caused by biofilm-forming bacteria in the dairy industry are a fundamental threat to safety and quality of milk products. Biofilm is a structured multicellular community encased in a self-produced extracellular matrix, which allow bacteria to survive in hostile environments. Bacillus species, which are major contaminants of dairy products can form biofilms on contact surfaces as well as within the milk products themselves. Thus, biofilms of Bacillus species represent continuous and persistent microbiological problems in the dairy industry, which can lead to serious economic losses due to food spoilage and equipment impairment. The objective of this study is to investigate the effect of magnesium ions on biofilm formation by Bacillus species within milk towards improving dairy products quality and safety. Our initial observations indicate that Mg²⁺ ions could prevent biofilm bundles formation by B. subtilis during growth within milk in a concentration dependent manner. Notably, bacterial growth was not significantly affected in a response to Mg²⁺ ions; hence, the mode of action of Mg²⁺ ions is apparently specific to inhibition of biofilm formation. We also show that the mode of action of Mg²⁺ ions is specific to inhibition of transcription of the extracellular matrix genes in B. subtilis. Our further observations indicate about hypersensitivity of bacterial cells, in the presence of Mg²⁺, to heat pasteurization undertaken during milk processing. Moreover, we found an improvement in technological properties of milk products such as soft cheeses by enriching them with magnesium. Finally, we report about a notable increase in intestine availability of magnesium from supplemented milk. In conclusion, milk products fortified with magnesium may provide qualitative and safer food for human consumption.