Application of Ultrasound Technology in Food Processing with emphasis on bacterial spores

Ultrasound technology is an emerging food processing technology that helps food processing/preservation shifting away from conventional thermal technologies due to their detrimental effects on food quality, composition, and sensory attributes. This review highlights the applications of ultrasound technology in food processing, and its prospects for eliminating microbial spores, important agents of food spoilage and foodborne intoxication/infection. Ultrasound (sound waves between 20–100 kHz and 2–10 MHz), when applied to foods, inhibits the proliferation of micro-organisms, extends shelf-life, and sustain food quality/sensory attributes. The generated sound waves induce intermolecular forces within the food medium and microbial cells, leading to cell wall rupture and cell lysis, and consequently inactivation. It has found application in the processing of various food items, including beef muscles, juices, oils, etc. The mode of microbial or bacterial spores’ inactivation includes cell wall and membrane disruption, inhibiting enzymatic activities and damaging DNA materials. As a tool for eliminating spores in foods, the technology is commonly used in combination with other treatments such as high temperature (thermosonication), high pressure (manosonication), and UV radiations. These combinations have been shown to improve foods’ physicochemical attributes while increasing spore permeability and sensitivity to other treatments, although through unclear mechanisms.