Mitigating Listeria Risk in Mung bean Sprouts Using Aerated Nanobubble Water

Mung bean sprouts are a widely consumed ready-to-eat product but are highly susceptible to contamination by Listeria monocytogenes (LM), a pathogen associated with severe illness. Existing decontamination strategies often fall short under commercial conditions. Thus, we evaluated the antimicrobial efficacy of aerated nanobubble water (AW) alone and in combination with peracetic acid (AP) as a multi-hurdle, user-friendly intervention to reduce LM contamination during sprout production. Mung bean seeds were inoculated with a five-strain LM cocktail (~4 log CFU/mL) and treated with one of four interventions: tap water (TW), aerated water (AW; ~30 mg/L O₂), TW + PAA (TP; 80 ppm), or AW + PAA (AP). Treated seeds were dried, stored for one month, and sampled periodically to quantify LM. In addition, at each sampling, seeds from each group were set up for sprouting, with aerated (AW/AP group) and tap water (TW/TP group) used as irrigation sources. Sprouts and spent irrigation water were sampled regularly for microbial and sprout quality analysis. Data were analyzed using R with significance tested at p≤0.05. AW and AP treatments significantly reduced LM on both seeds and sprouts compared to TW and TP. By day 21, LM was undetectable on AW- and AP-treated seeds, whereas TW- and TP-treated seeds retained ~2.8 and ~1.6 log CFU/mL, respectively. During sprouting, irrigation with AW or AP resulted in >3-4 log CFU/mL reduction in LM on sprouts. In contrast, TW and TP irrigations sustained high LM loads (~6-7 log CFU/mL). AW also reduced LM in spent irrigation water to undetectable levels. Importantly, AW significantly enhanced germination (by 18%), shoot length (by 22%), and sprout biomass (by 15%) relative to TW. Aerated nanobubble water, particularly in combination with PAA, is a promising antimicrobial and quality-enhancing intervention for improving microbial safety and production outcomes in mung bean sprouts.