Reduction of lactic acid bacteria and acetic acid bacteria from natural apple cider by UVC irradiation

Cider represents a habitat that allows the growth of different bacteria involved in the fermentation process. The process involves interactions between yeasts, lactic acid bacteria (LAB), and acetic acid bacteria (AAB). The activity of some bacteria is responsible for cider spoilage. This study examines the efficacy of UVC for reducing the microbial load in natural cider and characterizes the different LAB and AAB colonies. For this purpose, an inline UVC treatment has been designed and fabricated. Different flow rates have been tested. Moreover, the presence of the genes related to cider spoiling has been studied by PCR. The results have shown that UVC irradiation has been effective in all flow rates by reducing the bacterial load significantly, by 90%-99%. The presence of an enzyme related to bitterness has been found in some LAB. In conclusion, the developed UVC equipment has the potential effect of reducing the microbial load in the beverage. Novelty impact statement This article shows a significant reduction of the microbial load in beverages such as cider. The results show an important advance for the treatment of these beverages in the industry as it allows to control the microbial load present and increases the shelf life of the products. Furthermore, this research could increase the shelf life of the beverages in a market that is constantly growing.