Microbial safety and quality indicators of UV-treated tropical fruit beverages.

Abstract

The inactivation of Escherichia coli ATCC 25922, using a commercial UV light processing unit, in tropical fruit beverages (pineapple, blackberry, star fruit, soursop, mango, passion fruit, naranjilla, tamarind, hibiscus, and sour guava) was evaluated. Also, the effect on carotenoid content and microbial spoilage indicators (aerobic mesophilic bacteria and molds and yeasts counts) of UV light exposure (delivered UV dose: 14 mJ/cm² at 25 °C automatically adjusted by measuring the UV transmittance through the liquid) compared to thermal pasteurization (71.1 °C for 3 s) in a mango beverage was analyzed. A > 5 log reduction of E. coli was achieved in the pineapple, star fruit, soursop, mango, passion fruit, naranjilla, and tamarind beverages. The treatments did not significantly influence (p > 0.05) microbial spoilage indicators nor the carotenoid content in the mango beverage. Thus, the commercially used UV processing conditions evaluated are not suitable for the safety assurance of all tropical fruit beverages and, based on the spoilage and bioactive compound tested, both thermal and nonthermal approaches may be equally used in a mango beverage.