Preparation, physicochemical characterisation, storage stability and in vitro disinfectant activity of Tagetes minuta (L.) essential oil-loaded polycaprolactone nanocapsules against mastitis pathogens

This study focuses on the development of nanocapsules loaded with Tagetes minuta essential oil (TEO-NC) for milking management in sustainable dairy systems. The nanocapsules were prepared by nanoprecipitation, and their physicochemical properties were evaluated for 60 days at 4°C and 25°C. Antimicrobial and disinfectant activities were evaluated in the presence and absence of organic matter and on contaminated surfaces, such as rubber, stainless steel and ceramics. TEO-NCs had an average particle size of 266.67 ± 18.28 nm, polydispersity index (PdI) <0.12, zeta potential of 42.70 ± 1.08 and pH of 4.09 ± 0.08. Moreover, TEO-NCs showed no visual changes, and the physicochemical changes were minimal at the two temperatures tested. The minimum inhibitory concentration of TEO-NCs against Staphylococcus aureus was 50% (v/v). The disinfectant activity of TEO-NCs (100 and 50%, v/v) was demonstrated against Pseudomonas aeruginosa in the absence of organic matter after 5, 15 and 30 min. Disinfectant activity against S. aureus was demonstrated after 15 and 30 min (100%, v/v). In the presence of organic matter, the disinfectant activity of TEO-NCs (100%, v/v) was effective only against P. aeruginosa . Similarly, disinfectant activity of TEO-NCs against P. aeruginosa was demonstrated after 15 and 30 min on the three surfaces tested. Our results highlight the potential of T. minuta essential oils, a natural product, which, when combined with nanocapsules, results in a potential alternative for teat disinfection in milking management, especially in the control of environmental mastitis.