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 degrees C) and room (22 degrees 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 mu gmL(-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 degrees 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. (C) 2018 Elsevier Ltd. All rights reserved.