Antibacterial activity of crude extract of Tabernaemontana catharinensis latex (A. DC) against Alicyclobacillus spp.

Alicyclobacillus spp. is composed of Gram-positive, aerobic, thermoacidophilic, endospore-forming bacteria that cause food and beverage spoilage. The presence of Alicyclobacillus spp. may result in the production of guaiacol, which leads to sensory changes in the odour and taste of citrus juices and acidic foods. Tabernaemontana catharinensis (A. DC) is a plant belonging to the family Apocynaceae that produces milky latex with several biological activities described as antioxidant, antiviral, antimicrobial, trypanocidal and anti-leishmanicidal. Therefore, this study aims to evaluate the antimicrobial activity of the crude latex of T. catharinensis (A. DC) against microorganisms of the genus Alicyclobacillus spp. The minimum inhibitory concentration of latex was 7.81 μg/ml for the five Alicyclobacillus species analysed. The minimum bactericidal concentration for the species Alicyclobacillus acidoterrestris 0244T, A. hesperidum 0298T, A. acidiphilus 0247T and A. cycloheptanicus 0297T was 250 μg/ml. Cytotoxicity analysis demonstrated that latex was toxic to Vero cells at concentrations greater than 84.67 μg/ml. Scanning electron microscopy revealed changes in the cell wall of A. acidoterrestris 0244T present in orange juice when treated with crude latex. The results obtained suggest that the crude latex of T. catharinensis (A. DC) displays an antimicrobial effect against Alicyclobacillus, with potential for application in the food industry.