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Study finds climate change could worsen microbial contamination of raw milk

Study finds climate change could worsen microbial contamination of raw milk

Climate change could have a big impact on the microbiological quality of raw milk in Europe, according to a study.

While many organisms suffer from the increased temperatures of climate change, some E. coli strains seem to be thriving. The danger is they have the potential to adapt to withstand the pasteurization process.

Unpasteurized, raw milk is consumed in several European countries including France. A model was developed to quantify the concentration of E. coli in raw milk and see what may happen in France under changing weather conditions. It included initial contamination, packaging, retailing, and consumer refrigeration.

Initial microbial counts were from a dairy in Saudi Arabia in 2019 to reflect the impact of hot weather and show what could happen in Europe in the future because of climate change.

At the farm, it was assumed that temperature of the milk cooling tank complied with French legislation of below 4 degrees C (39.2 degrees F). Data are E. coli counts from bulk milk tanks, collected and analyzed as part of routine quality control monitoring. They were used to assess contamination just after the milking step.

Microbial growth was determined through various scenarios of time and temperature storage reflecting the raw milk supply chain in France, according to the study published in Food Research International.

Consumer storage impact
The average initial concentration of E. coli in raw milk was estimated to be 1.31 log colony forming units (CFU) per milliliter and this has been shown to increase at the end of the supply chain depending on public storage times and temperatures.

In France some predictions of initial contamination were already above the 2 log limit for E. coli. Presence of high amounts of E. coli signifies fecal contamination, which is an indicator of hygiene at dairies.


Climate change could have a big impact on the microbiological quality of raw milk in Europe, according to a study. While many organisms suffer from the
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