Microwave technology as a new tool to improve microbiological control of oak barrels: A preliminary study

This study presents a novel microwave technology application which investigates the ability of a new equipment prototype, based on high frequency microwaves, to reduce microbial populations in oak wine barrels. American and French oak staves from highly contaminated barrels were treated. It was demonstrated that microwave treatment was able to significantly decrease the main wine associated microorganism populations from the first 8 mm of oak surfaces. However, the reduction in viable counts depended on the studied microorganism. Thus, counts were reduced by 36%–38% for total yeast, from 35% to 67% for Brettanomyces and around 91%–100% for lactic acid bacteria and acetic acid bacteria, using a very short treatment time (3 min). Nowadays, there is not a convenient method for decontaminating barrels and microwave technology may be a more efficient treatment than currently available methods. Findings from this research suggested that microwave would be beneficial for wine industry and environment by increasing barrel functionality, reducing frequency of replacement, improving microbiological control of oak wood, as well as minimizing of preservative use.