Intervention Methods To Improve The Microbiological Safety And Quality Of Juices.
Juices and beverages have increased in production and consumption in the U.S. over the last several decades due to health benefits and convenience. However, Alicyclobacillus, a significant spoilage bacterium in the juice s and beverages, and patulin, a heat stable mycotoxin commonly associated with apple juice and cider, are critical concerns for juice and beverage industry. Non-thermal treatments and techniques have been investigated as potential methods to control patulin and Alicyclobacillus in juices. Ultraviolet radiation (UV) was used to control patulin in apple juice from concentrate (UV exposure from 14.2 to 99.4 mJ/cm2) and kinetic degradation models between apple cider and apple juice from concentrate were compared. UV radiation was shown to effectively reduce patulin with minimal cha nges in physicochemical properties and sensory characteristics of apple juice from concentrate. Patulin reduction by UV radiation in apple juice from concentrate followed first -order kinetics. Dimethyl dicarbonate (DMDC) with 0, 50, 125, and 250 ppm, and papain and bromelain (0, 100, and 1000 ppm) were used to investigate the inhibitory effect of vegetative cells and spores of Alicyclobacillus acidoterrestris strains VF, WAC, and SAC in potato dextrose broth (PDB), apple juice, and orange juice. DMDC showed a significant reduction in vegetative cells and spores of Alicyclobacillus in all samples, with no changes in juice quality, whereas, papain and bromelain showed antimicrobial activity only against vegetative cells of all strains with all samples, and minimal alterations in juice quality and sensory attributes. Various media and potential bacteriocin-producing lactic acid bacteria (LAB) were evaluated as alternative biopreservation methods to control Alicyclobacillus. Potato dextrose agar pH 3.5 (PDA) was the only medium that allowed the growth of Alicyclobacillus whereas sodium citrate and dipotassium phosphate (APT ingredients) inhibited Alicyclobacillus species. No potential bacteriocin-producing LAB were isolated from kimchi and fermented apple slurries. Non-thermal treatments including non-thermal processing and natural antimicrobial compounds were investigated as alternative treatments to enhance the microbiological safety and quality of juices. The physicochemical and sensory properties of these alternative methods need to be preserved which assists in promoting the juice and beverage market through enhancing consumer's trust by ensuring consistently wholesome and safe products.
Worobo, Randy W.
Padilla-Zakour, Olga I.; Smart, Christine Durbahn
Food Science and Technology
Ph. D., Food Science and Technology
Doctor of Philosophy
dissertation or thesis