Harnessing the Natural Acidity of Raw Passion Fruit Juice for Pathogen Inactivation in Developing Countries

Unpasteurized fruit juices in developing countries pose significant public health risks due to potential contamination with foodborne pathogens, particularly in rural areas where reliable energy for thermal processing is lacking. This study evaluates the natural acidity of passion fruit juice as a non-thermal strategy to inactivate Salmonella ser. Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes. Pathogens were inoculated into passion fruit juice at pH 2.9, 3.4, and 3.9, and their survival was monitored at 25 °C (room temperature) and 5 °C (refrigerated). Log-linear and Weibull models were used to predict inactivation kinetics, targeting a 5-log reduction in accordance with FDA requirements. At pH 2.9 and 5 °C, S. Typhimurium and E. coli achieved a 5-log reduction within 8 h, while L. monocytogenes required 24 h to achieve the same reduction level. The Weibull model provided a superior fit (R2 > 0.94) at pH 2.9 and 3.4, accurately capturing the nonlinear inactivation dynamics. Increasing pH to 3.9 significantly slowed inactivation, underscoring the critical role of low pH. These findings suggest that the inherent acidity of passion fruit juice provides a practical, energy-independent method for controlling pathogenic bacteria in developing regions, preserving nutritional quality without thermal processing.