Chronic Bovine Mastitis: A Food Safety Issue and Public Health Hazard

Milk is a nutrient dense liquid containing fats, proteins, carbohydrates and vitamins which provides an ideal matrix for the growth of many pathogenic microbial species. The presence of intramammary infections in bovine species has a significant impact on the dairy industry due to losses in the quantity and quality of milk. Causative agents of disease may gain entry into milk-based food items at any stage of food production and is typically an indicator of poor manufacture practices. Species such as S. aureus, S. uberis, S. agalactiae, E. coli and Pseudomonas have been known to induce sub-clinical or clinical mastitis which may persist chronically. In addition to possessing antimicrobial resistance mechanisms, these species are often adapted to the host immune system with virulence factors enabling them to colonize and thrive within the mammary gland. Therefore, while providing an invaluable food source to countless people globally, dairy produce may also act as a reservoir for disease and morbidity to consumers. The World Health Organization has listed Enterobacteriaceae and Pseudomonas as critically important on its watch list of priority pathogens challenging human safety. As such, the bacteriological safety of milk and dairy food represents a serious health hazard which producers must overcome. The association between food and nutrition impact on human and animal health related quality of life and economics is an important aim of the One Health approach. Efficient farm and milk management programs including optimal treatment of clinical mastitis cases, culling of non-responsive cows, cow teat and machine disinfection and maintenance is essential in controlling mastitis outbreaks within herds.