Stress response in bacteria originated from dairy products

In some bacteria, the stress adaptation response, a defence mechanism against low pH, can also induce a number of physiological and genetic resistance mechanisms that provide advantages for bacteria to resist other environmental factors. This phenomenon is called cross-protection, which can potentially have serious consequences for food safety. In some fermented, acidified foods, low pH can provide a favourable environment for the growth of bacteria. Bacteria can adapt to acidic environments and become able to survive various factors that occur during storage and processing such as salt, antibiotics, or technological effects.

The microbiota of dairy products includes beneficial microorganisms, spoilage bacteria, and foodborne pathogens. The most common bacteria on various dairy products are Escherichia coli, Enterococcus sp., Staphylococcus sp., and Bacillus sp.

The aim of this research is to determine the resistance of the identified bacteria (16S rDNA-based bacterial identification) to antibiotics and osmotic pressure as a consequence of their possible defence mechanisms adapted to the acidic environment.