Effect of ultraviolet treatment (UV–C) combined with nisin on industrialized orange juice in Alicyclobacillus acidoterrestris spores

Abstract

Alicyclobacillus acidoterrestris is a bacteria capable of spoiling industrialized orange juice, making it a problem for the beverage industry. This study evaluated the effect of UV-C radiation in combination with nisin in the reduction of A. acidoterrestris spores using reconstituted orange juice. A. acidoterrestris spores were treated with nisin (7.81 and 15.62 μg/mL) in combination with different doses of UV-C (from 2.52 to 12.6 kJ/m2). The presence of vitamins in the juice after the treatments was investigated by UHPLC-HRMS using a ultra high performance liquid chromatography system. The combination of UV-C and nisin treatment showed counts below the detection limit of the method (<1.7 log CFU/mL) both at time 6 min (5.04 kJ/m2) with 7.81 μg/mL nisin and at time 3 min (2.52 kJ/m2) with 15.62 μg/mL nisin (p < 0.05). Ascorbic acid was found in control and 3-min UV-C samples, but with 15 min of treatment the vitamin was not detected. Thiamine was found in the three samples analyzed (T0, T3 and T15). Treatment with UV-C combined with low dose nisin (2.52 kJ/m2) eliminated spores without degrading the analyzed juice vitamins and is a promising alternative for the beverage industry.