Dynamic modelling of Listeria monocytogenes in milk: pH and LAB effects
Our collaborators have a new article in Foods on how initial milk pH and lactic acid bacteria (LAB) strains shape the growth of Listeria monocytogenes in a milk model medium.
Citation: Y. Loforte, M. Zanzan, V. Cadavez, U. Gonzales-Barron. 2025. “Dynamic Modelling of Listeria monocytogenes Growth in a Milk Model Medium as Affected by pH and Selected Lactic Acid Bacteria Strains.” Foods 14(23):3999. DOI: https://doi.org/10.3390/foods14233999.
Quick summary
- Tested three LAB strains (Leuconostoc mesenteroides, Lacticaseibacillus paracasei, Loigolactobacillus coryniformis) in monoculture and co-culture with L. monocytogenes.
- Milk was adjusted to three initial pH levels: 5.5, 6.0, and 6.5.
- Growth curves were modeled with a pH-driven approach and a Jameson-effect model; the pH-driven model gave more precise estimates.
Key findings
- pH matters: Higher starting pH led to higher maximum concentrations of L. monocytogenes in both mono- and co-culture.
- LAB control: All three LAB strains reduced the pathogen’s maximum concentration; in co-culture, L. mesenteroides was especially effective by slowing Listeria growth rates.
- Practical lever: Acidifying milk before fermentation adds a barrier against L. monocytogenes, complementing LAB inhibitory effects.
Why it matters
Better understanding of how pH and specific LAB strains interact with Listeria informs safer dairy fermentations and supports predictive microbiology for risk management—directly relevant to food safety in agro-pastoral systems.
Access
Read the paper: https://doi.org/10.3390/foods14233999
Affiliations: CIMO, LA SusTEC, Instituto Politécnico de Bragança; Instituto Superior Politécnico de Manica.