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[Listeria monocytogenes in pasteurized milk]
Canadian Journal of Microbiology
|February 1, 1986
Summary
Pathogenic Listeria monocytogenes strains were found in 21.4% of pasteurized milk samples in Madrid. This highlights pasteurized milk as a potential source of human listeriosis outbreaks.
Area of Science:
- Food microbiology
- Bacteriology
- Public health
Context:
- Pasteurized milk is a widely consumed product.
- Listeria monocytogenes is a significant foodborne pathogen.
- Previous studies have indicated potential contamination of dairy products.
Purpose:
- To investigate the prevalence of Listeria species, including pathogenic strains, in pasteurized milk from a Madrid processing plant.
- To assess the risk of Listeria contamination in pasteurized milk.
Summary:
- A study isolated an haemolytic Listeria monocytogenes strain pathogenic to mice from 6 out of 28 (21.4%) pasteurized milk samples.
- Listeria grayi was the most frequently detected species (89.2%), followed by L. innocua (10.7%).
- Other Listeria species, including L. welshimeri, were also identified, but L. ivanovii, L. seeligeri, L. murrayi, and L. denitrificans were not found.
Impact:
- Demonstrates that pathogenic Listeria strains can survive pasteurization and be present in milk.
- Reinforces the hypothesis that pasteurized milk is a potential vehicle for human listeriosis transmission.
- Underscores the importance of stringent quality control in milk processing to ensure food safety.