Efficient Reduction of Pathogenic and Spoilage Microorganisms from Apple Cider by Combining Microfiltration with UV Treatment

Abstract

Thermal pasteurization can achieve the U. S. Food and Drug Administration-required 5-log reduction of pathogenic Escherichia coli O157:H7 and Cryptosporidium parvum in apple juice and cider, but it can also negatively affect the nutritional and organoleptic properties of the treated products. In addition, thermal pasteurization is only marginally effective against the acidophilic, thermophilic, and spore-forming bacteria Alicyclobacillus spp., which is known to cause off-flavors in juice products. In this study, the efficiency of a combined microfiltration (MF) and UV process as a nonthermal treatment for the reduction of pathogenic and nonpathogenic E. coli, C. parvum, and Alicyclobacillus acidoterrestris from apple cider was investigated. MF was used to physically remove suspended solids and microorganisms from apple cider, thus enhancing the effectiveness of UV and allowing a lower UV dose to be used. MF, with ceramic membranes (pore sizes, 0.8 and 1.4 μm), was performed at a temperature of 10 °C and a transmembrane pressure of 155 kPa. The subsequent UV treatment was conducted using at a low UV dose of 1.75 mJ/cm(2). The combined MF and UV achieved more than a 5-log reduction of E. coli, C. parvum, and A. acidoterrestris. MF with the 0.8-μm pore size performed better than the 1.4-μm pore size on removal of E. coli and A. acidoterrestris. The developed nonthermal hurdle treatment has the potential to significantly reduce pathogens, as well as spores, yeasts, molds, and protozoa in apple cider, and thus help juice processors improve the safety and quality of their products.

Nonthermal Technologies for Fruit and Vegetable Juices and Beverages: Overview and Advances

“…In this respect, the application of external fields such as US is expected to mitigate the concentration polarization resulting in higher flux rates (Chanukya and Rastogi, ). Zhao and others () combined MF and UV achieving more than a 5 log reduction of E. coli , Cryptosporidium parvum , and Al. acidoterrestris in apple cider.…”

Food Safety Modernization Act Produce Safety Rule Compliance for United States Hard Cider Producers Using Ground-harvested Apples

“…Membrane filtration is also a technique that may reduce microbial populations in juice. Zhao et al (2015) found that a 5-log reduction in E. coli O156:H7 was achievable using 0.8-mm membrane pore size and a 4.6-log reduction when using a 1.4-mm membrane pore size. For both membrane sizes, C. parvum oocysts also were completely removed.…”

“…For both membrane sizes, C. parvum oocysts also were completely removed. Furthermore, removal of suspended solids through the filtration process increased the efficacy of the ultraviolet radiation treatment (Zhao et al, 2015).…”

Fruit Juice Production Using Ultraviolet Pasteurization: A Review

“…Some combined treatments has the potential to significantly reduce a variety of pathogens, spores, yeasts, molds, and protozoa. The combined membrane filtration and UV achieved more than a 5-log reduction of E. coli, C. parvum, and A. acidoterrestris [83]. Gram-negative bacteria, E. coli O157:H7, S. typhimurium, and S. cerevisiae counts were significantly reduced after a combined treatment using TUVP and high pressure [84].…”