Inhibition of Salmonella Typhimurium growth in coconut (Cocos nucifera L.) water by hurdle technology

The aim of this study was to evaluate a hurdle technology approach (ultraviolet-C light treatment, vanillin or cinnamaldehyde and storage temperature) for preventing the growth of Salmonella Typhimurium inoculated into coconut water. Inoculated coconut water was treated with UV-C light at different times (3.5, 7 and 10.5 min); immediately, selected natural antimicrobials (vanillin and cinnamaldehyde) were added at fixed concentrations and stored under refrigeration (5 °C) and room (22 °C) temperatures for 30 days. Beta model was used for describing either growth or death kinetics of S. Typhimurium. By themselves, antimicrobials significantly decreased S. Typhimurium counts achieving a maximum reduction of 1.4 ± 0.3 log CFU mL−1 with cinnamaldehyde (100 μg mL−1). Natural antimicrobials and low temperature significantly affected (p < 0.05) S. Typhimurium growth during storage. A 7-min UV-C light exposure allowed the inhibition of S. Typhimurium growth in coconut water containing natural antimicrobials over a 30-day storage at 5 °C. Moreover, a 10.5-min UV-C light treatment per se prevented S. Typhimurium growth in coconut water, regardless of any other hurdles applied. Beta model satisfactorily fits the experimental data. Results might be used for developing a low-cost preservation method for coconut water.