Evaluation of the effectiveness of essential oil tea tree (Melaleuca alternifolia) against three bacterial genera isolated from bovine mastitis

Bovine mastitis, a disease with a global negative impact on the dairy industry, is responsible for the spread of multidrug-resistant bacteria. This study evaluated the antimicrobial effectiveness of tea tree essential oil (Melaleuca alternifolia) against Escherichia coli, Klebsiella spp., and Staphylococcus aureus, pathogens previously isolated from bovine mastitis. The essential oil was obtained through steam distillation, revealing a yield of 2.12% of oil in relation to the volume of plant material. The evaluated concentrations (75%, 50%, 30%, 20%, and 10%) showed highly significant statistical differences (p 0.05) in the inhibition zones. Volatile compounds were identified through gas chromatography and mass spectrometry, with L-terpinen-4-ol standing out as predominant (34.02% area). It was concluded that a minimum concentration of 50% of the essential oil is needed to completely inhibit the bacteria causing bovine mastitis, emphasizing the relevance of L-terpinen-4-ol in the antimicrobial activity. These findings highlight the potential of tea tree essential oil as an antimicrobial agent in the fight against bovine mastitis, with significant implications for health and productivity in the global dairy industry.