Inhibition of Listeria monocytogenes and Escherichia coli O157:H7 in liquid broth medium and during processing of fermented sausage using autochthonous starter cultures

- Autochthonous starter cultures used in vitro and in situ assays.
- Inactivation of L. monocytogenes and E. coli O157:H7 occurred.
- The inactivation rate in vitro of E. coli O157:H7 was greater than L. monocytogenes.
- “Log-linear+tail” GInaFit model applied in situ assays.
- A 2.2-log reduction of E. coli O157:H7 occurred during sausage processing.

The antimicrobial effect of two autochthonous starter cultures of Lactobacillus sakei was evaluated in vitro (in liquid broth medium) and in situ assays. The inactivation of foodborne pathogens Listeria monocytogenes (serotype 4ab No 10) and Escherichia coli O157:H7 ATCC 43888 was investigated during the production of fermented sausage according to a typical Greek recipe using L. sakei strains as starter cultures. The inactivation kinetics were modeled using GInaFiT, a freeware tool to assess microbial survival curves. By the end of the ripening period, the inhibition of L. monocytogenes was significant in treatments with L. sakei 8416 and L. sakei 4413 compared to the control treatment. A 2.2-log reduction of the population of E. coli O157:H7 resulted from the autochthonous starter culture L. sakei 4413 during sausage processing. The use of the autochthonous starter cultures constitutes an additional improvement to the microbial safety by reducing foodborne pathogens.