Control of meat spoilage with ozone nano-bubbles: Insights from laboratory model systems and commercial scale treatments
Zhaohui Xu, Janik Hettinger, Alex Athey, Xianqin Yang, Michael G. Gänzle
Abstract
Ozone nanobubbles represent an environmentally friendly sanitation agent. In this study, we compared the bactericidal effect of ozone nanobubbles on pork muscle and adipose tissue to peracetic acid treatments. Pork samples were surface-inoculated with a cocktail of common meat-spoilage-associated microorganisms composed of Brochothrix thermosphacta , Latilactobacillus sakei , Leuconostoc gelidum , Carnobacterium maltaromaticum , Hafnia paralvei and Yersinia rohdei at a viable cell count of 10 2 CFU/cm 2 or 10 4 CFU/cm 2 . Both freshly inoculated and stored pork samples were treated with the two sanitation agents, followed by differential enumeration of viable bacteria. Ozone nanobubbles were comparable to peracetic acid solution, achieving a reduction between 1 and 2 log (CFU/cm 2 ), regardless of the initial inoculum concentration and sample type. The efficacy of ozone nanobubble increased with increased solution volume and flow rate. Moreover, the sanitizing agents differentially impacted the members of the microbiota and shifted the composition of tested strains during storage. Gram-negative Y. rohdei and H. paralvei were more sensitive to peracetic acid than Gram-positive strains. Microbial profiling using 16S rRNA gene amplicon analysis of samples that were treated at a commercial processing scale revealed that Serratia , Carnobacterium , Yersinia , Vagococcus , Morganella , Dellaglioa were the dominant taxa (relative abundance >1 %) on stored pork samples. The use of ozone nanobubbles significantly reduced the relative abundance of Vagococcus and Clostridium when compared to control samples. In summary, ozone nanobubbles are an effective tool to reduce bacterial counts on meat and show promise to extend the shelf life of fresh meat. • Lethality of ozone nanobubbles against meat spoilers was compared to peracetic acid. • Ozone nanobubbles reduced cell counts on meat by 0.5–1 log(CFU/cm 2 ). • The effect of ozone was comparable to peracetic acid for most target microbes. • Increased flow of ozone nanobubbles increased their lethality. • Laboratory results were validated for commercial-scale pork production.