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Isolation of yeasts from bovine milk in Belgium
P E Lagneau1, K Lebtahi, D Swinne
1Fédération du Hainaut de Lutte contre les Maladies du Bétail, Mons.
Abstract:
A total of 436 milk samples from non-infected and 80 from infected quarters were investigated: 24.5% of the samples collected from non-infected and 55% of those collected from infected quarters were positive. Normal milk yielded not less than 16 different species and among them many potentially pathogenic yeast species such as C. parapsilosis, C. guilliermondii, C. tropicalis, C. glabrata and T. asahii, all five able to grow at 40 degrees C. In contrast, the yeasts isolated from infected quarters were from 3 species: C. kefyr, C. catenulata and C. lambica, which were also among the yeasts species recovered from normal milk. Among the three species, only one i.e. Candida kefyr is able to grow above 40 degrees C and from there can be considered as potentially pathogenic, even if bacterial association is necessary to cause mastitis.
Insights
Yeast species were identified in milk samples from both healthy and infected udders. Candida kefyr, found in infected milk and capable of growing at high temperatures, is considered potentially pathogenic for bovine mastitis.
Area of Science:
- Veterinary Mycology
- Dairy Science
- Animal Health
Background:
- Yeast contamination in milk can impact udder health.
- Identifying yeast species and their thermal tolerance is crucial for understanding mastitis etiology.
Purpose of the Study:
- To investigate and compare yeast species found in non-infected and infected bovine milk samples.
- To assess the pathogenic potential of isolated yeast species based on their thermal growth characteristics.
Main Methods:
- Analysis of 436 milk samples from non-infected quarters and 80 from infected quarters.
- Isolation and identification of yeast species from milk samples.
- Evaluation of yeast growth at elevated temperatures (40°C).
Main Results:
- Positive yeast detection rates were 24.5% in non-infected and 55% in infected samples.
- Non-infected milk yielded at least 16 yeast species, including potentially pathogenic ones like Candida parapsilosis and Candida tropicalis.
- Infected quarters yielded three species: Candida kefyr, Candida catenulata, and Candida lambica, with only Candida kefyr showing growth above 40°C.
Conclusions:
- Candida kefyr, isolated from infected milk and thermotolerant, is a potential pathogen for bovine mastitis.
- Bacterial co-infection may be necessary for Candida kefyr to cause clinical mastitis.