Abstract
Spore-forming bacteria are a great concern for fruit juice processors as they can resist the thermal pasteurization and the high hydrostatic pressure treatments that fruit juices receive during their processing, thus reducing their microbiological quality and safety. In this context, our objective was to evaluate the efficacy of Ultraviolet-C (UV-C) light at 254 nm on reducing bacterial spores of Alicyclobacillus acidoterrestris, Bacillus coagulans and Bacillus cereus at two stages of orange juice production. To simulate fruit disinfection before processing, the orange peel was artificially inoculated with each of the bacterial spores and submitted to UV-C light (97.8–100.1 W/m2) with treatment times between 3 s and 10 min. The obtained product, the orange juice, was also tested by exposing the artificially inoculated juice to UV-C light (100.9–107.9 W/m2) between 5 and 60 min. A three-minute treatment (18.0 kJ/m2) reduced spore numbers on orange peel around 2 log units, while more than 45 min (278.8 kJ/m2) were needed to achieve the same reduction in orange juice for all evaluated bacterial spores. As raw fruits are the main source of bacterial spores in fruit juices, reducing bacterial spores on fruit peels could help fruit juice processors to enhance the microbiological quality and safety of fruit juices.
Highlights
The microbial population of fruit and vegetable juices depends on the agricultural practices used to obtain the raw materials, the employees’ health and hygiene and the source of agricultural water, as well as on the production practices and the hygienic conditions of the processing plant
The initial population of A. acidoterrestris CECT 7094T, A. acidoterrestris titratable acidity (TA)-1.183, B. cereus and B. coagulans spores on orange peel was 5.07 ± 0.11, 4.92 ± 0.03, 4.80 ± 0.10 and 5.01 ± 0.09 log CFU/cm2, respectively
CECT 7094T, A. acidoterrestris TA-1.183, B. cereus and B. coagulans spores were reduced by 2.28 ± 0.21, 2.08 ± 0.23, 2.27 ± 0.30 and 2.05 ± 0.23 log, respectively
Summary
The microbial population of fruit and vegetable juices depends on the agricultural practices used to obtain the raw materials, the employees’ health and hygiene and the source of agricultural water, as well as on the production practices and the hygienic conditions of the processing plant. Thermal pasteurization is widely used during fruit and vegetable juice processing to ensure its microbial safety and quality, thermal treatments are detrimental for juice organoleptic and nutritional quality. HPP is widely used to pasteurize juices of superior quality as it does not produce heat-related deterioration like loss of vitamins and nutrients, discoloration and textural and organoleptic changes [5]. Both thermal pasteurization and HPP treatments of fruit and vegetable juices are able to inactivate bacterial vegetative forms. They have been reported to withstand at least 1000 MPa, which is 400 MPa higher than the maximum pressure currently achievable in commercial food processing [6]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call