Effect of Ultrasound with Acetic Acid on Natural Contaminant Microbiota and Physicochemical Characteristics of Cherry Tomatoes

Lam, Jia Xin (2018) Effect of Ultrasound with Acetic Acid on Natural Contaminant Microbiota and Physicochemical Characteristics of Cherry Tomatoes. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Sanitization is a significant step for food industry to inactivate the spoilage microorganism and pathogenic microbe. Sanitization using the chemical compound like chlorine to inactivate the microbe will affect the consumer health. Therefore, recently there is new method develop which using ultrasound to remove natural contaminant and inactivate microbe on vegetables and fruit in a more safety way. The present study used cherry tomatoes and involved three treatments which are no sanitizer (NS, control treatment), acetic acid (AA) and acetic acid with ultrasound (AA+US). The ultrasound treatment used 25kHz on frequency and 650W of power. All of the treatments will occur for 10 minutes and the quality of cherry tomatoes over 9 days of storage at 8℃ was studied. This study had analyzed the natural contaminant microbiota (mesophilic aerobic bacteria, mold and yeasts) and physicochemical quality (pH, total soluble solid, color and vitamin C) on cherry tomatoes. The objective of this study were to determine which treatment have the most decimal reduction on mesophilic aerobic bacteria, and mold and yeast compared to control treatment, and also to determine whether three of the treatment will cause the changes on physicochemical characteristic of cherry tomatoes. After this study had conducted, the best treatment was acetic acid with ultrasound (AA+US) and this treatment had more reduction on natural contaminant microbiota compared to acetic acid treatment. Synergistic effect could be observed between acetic acid solution and ultrasound treatment. Besides, there were no distinct changes on the physicochemical characteristics of cherry tomatoes during the 9 days of storage. Therefore, ultrasound is a better method to decrease the natural contaminant microbiota without having major changes on cherry tomatoes quality.