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Publication
Controlling Listeria monocytogenes contamination in fresh goat milk cheeses: Dynamic modelling during storage
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Advisor(s)
Abstract(s)
Predictive models applied for artisanal fresh goat cheeses are invaluable tools for rapid decision-making in
quality and safety management. Listeria monocytogenes is a common foodborne pathogen associated with recent
safety alerts in ready-to-eat (RTE) products in Andalucia. Managing artisanal production variables, such as
storage conditions and final product features (pH or water activity [aw]) might be crucial for controlling
L. monocytogenes in these traditional products. This study evaluated the time-temperature dependence of
L. monocytogenes during shelf-life of fresh goat milk cheese artisanally produced in Andalucía. The effect of
storage temperature (4–25 ◦C) over 5–20 days was tested in lab-scale fresh goat milk cheeses initially inoculated
with a three-strain cocktail of the pathogen (ca. 2–3 log cfu/g). The Huang (model A) and Baranyi (model B)
models coupled with Ratkowsky were fitted to the collected growth data to describe the relationship between
L. monocytogenes concentration, growth rate (μmax, log cfu/d), storage temperature, and time. The results
highlighted the higher variability of growth data at 4 ◦C, the linear relationship between μmax and temperature,
the inverse correlation between ymax (exceeding 5 log cfu/g at all the temperatures) and ΔY (with a maximum of
4.386 and minimum of 2.461, at 4 and 25 ◦C, respectively) and a faster decrease of pH at higher temperatures.
Model validity, assessed through goodness-of-fit and both internal and external validations (under both
isothermal temperatures and a dynamic temperature workflow simulating real production scenario), revealed
good model adjustment to L. monocytogenes growth in artisanal commercial cheeses, after determining a
correction factor of 1.806 and 1.856, for models A and B, respectively. Predictions indicated that an initially
contaminated artisanal fresh goat milk cheese would not meet regulatory limits after 4 days under refrigeration
conditions (4 ◦C), aerobic conditions, or opened packaging. These results highlight the potential public health
risk of artisanal fresh goat milk cheeses related to L. monocytogenes transmission if manufacturing and storage
conditions are not well controlled, emphasizing the need for stringent microbial control efforts and mitigation
measures.
Description
Keywords
Listeriosis Shelf-life Artisanal production Challenge test Model validation
Citation
Bonilla-Luque, Olga María; Possas, Arícia; Gonzales-Barron, Úrsula; Cadavez, Vasco; Ezzaky, Youssef; Hussein, Abdelraheem; Valero, Antonio (2025). Controlling Listeria monocytogenes contamination in fresh goat milk cheeses: dynamic modelling during storage. Food Control. ISSN 0956-7135. 174, p. 1-12
Publisher
Elsevier BV