Decontamination of alfalfa and mung bean sprouts by ultrasound and aqueous chlorine dioxide

- Similar levels of bacteria reduction on the sprouts were found after US or ClO2 treatment.
- ClO2 treatment was more effective than US in total bacteria inactivation.
- Additive effect on bacteria reduction of sprouts was found when both treatments were combined.

The antimicrobial effect of ultrasound, aqueous chlorine dioxide (ClO2) and the combination of both treatments was assessed on Escherchia coli and Salmonella enteritidis inoculated on alfalfa and mung bean sprouts were performed for 5 min. This work presents the first approach regarding the using of the previously mentioned technologies on the decontamination of inoculated sprouts. Ultrasound (26 kHz, 90 μm, 200 W) process was able to reduce by 1.40 ± 0.40 and 1.89 ± 0.51 log CFU/g Salmonella and by 1.06 ± 0.32 and 1.23 ± 0.40 log CFU/g of E. coli on alfalfa and mung bean sprouts, respectively. ClO2 (3 ppm) reduced the population of the studied bacteria in similar levels (≈1.5 log CFU/g) both in alfalfa and mung bean sprouts. However, ClO2 treatment was more effective than the ultrasound process in terms of E. coli and Salmonella total inactivation (i.e., water and sprouts) both in alfalfa and mung bean sprouts. Additionally, an additive effect was observed in the reduction of both E. coli and Salmonella and the total inactivation when ultrasound was combined with ClO2 in all tested food products.