Comparative efficacy of cold plasma and ozone treatments in mitigating Aspergillus flavus and Aflatoxin B1 in Byadagi chili

Abstract

This study evaluates and compares the efficacy of cold plasma (CP) and ozone treatments in reducing Aspergillus flavus contamination and mitigating aflatoxin B1 (AFB1) levels in Geographical Indication (GI)-tagged Byadagi chili. CP was applied at 10–20 kV for 10–20 min with a 5 cm electrode gap, while ozone treatment was performed at a flow rate of 5 LPM for 10–40 min. Post-treatment assessments were conducted on immediately, 7 and 15 days of storage to evaluate treatment's prolonged efficacy. The most effective CP treatment (20 kV, 20 min) achieved a 3.18 log reduction in A. flavus immediately, with reductions increasing to 3.78 logs on day 7 and 3.88 logs by day 15. Ozone treatment showed a 3.48 log reduction initially, with continued suppression up to 3.97 logs by day 15, while the control exhibited progressive microbial growth. Both CP and ozone inhibited AFB1 formation by 84.78 % and 86.42 %, respectively, and degraded spiked AFB1 by 65.64 % (CP) and 69.10 % (ozone). During post-treatment, no significant visual or structural alterations were detected, as confirmed by colorimetric, FTIR, and SEM analyses. These findings demonstrate that CP and ozone are effective, non-thermal, chemical-free strategies for reducing microbial and mycotoxin risks in dried spices. The study proposes a scalable dual-treatment approach, ozone pre-treatment followed by CP during packaging, offering an innovative solution for large-scale processing of high-value spices.