coli O157:H7, Salmonella Typhimurium, and L. (2014) reported combined simultaneous application of ozone and heat at 25☌, 45☌, 50☌, and 55☌ for inactivation of E. HHP, high hydrostatic pressure PEF, pulsed electric fields PL, pulsed light TUVP, UV-TiO 2-photocatalytic oxidation. Gram-negative bacteria with a thin peptidoglycan layer inside of the outer cell membrane are likely more susceptible to pressure than Gram-positive bacteria that have a thick superficial peptidoglycan layer that can cause resistance to HHP ( Patterson, 2005 Shahbaz et al., 2016a). Gram-positive and Gram-negative bacteria have different structural characteristics that result in different responses to HHP treatment. Gram-negative Salmonella Typhimurium was most sensitive to a separate UV-TiO 2 photocatalysis treatment ( Shahbaz et al., 2016a). The sensitivity order of bacteria to HHP at 600 MPa for 1 min in apple juice was Salmonella Typhimurium> L. HHP treatment at pressure levels of 200 and 300 MPa showed nonsignificant effects against Gram-positive bacteria inoculated into apple juice. Bacterial pathogens have shown variable degrees of sensitivity to HHP treatment ( Hiremath and Ramaswamy, 2012 Patterson, 2005). monocytogenes to achieve complete disinfection of apple juice ( Shahbaz et al., 2016a). Combined sequential treatments of TUVP followed by HHP effectively inactivated E. A synergistic effect was observed using combined sequential treatments for inactivation of different microorganisms. (2016a) investigated the effects of HHP and UV-TiO 2 alone, and for combined treatments, on microbial inactivation in commercial apple juice used as model liquid food. Table 18.1 summarizes inactivation of pathogens in apple juice subjected to different processing treatments. Apple juice has been widely used as a medium for evaluation of microbial inactivation. rhamnosus, respectively.Īpple juice is a popular fruit juice due to pleasant organoleptic qualities and outstanding nutritional properties ( Muñoz et al., 2012 Choi et al., 2012).
(2002) measured the inactivation of different microorganisms in apple juice (pH 3.4) after PEF with 34 kV/cm and an initial temperature of 55 ☌, with specific energy input 40 kJ/kg as 6.2, 6.5, 4.3, and 4.9 log reductions for E. cerevisiae in apple juice with 20 kV/cm and 10.4 square wave pulses. (2000) showed that PEF treatment at 35 kV/cm for 94 μs total treatment time significantly extended the shelf-life of apple juice and apple cider while no change was measured in ascorbic acid content. (1997) reported a shelf-life of PEF-treated apple juice (with 16 pulses) as long as eight weeks when stored at room temperature (22–25 ☌), without any apparent change in physicochemical and sensory properties. cerevisiae inoculated in apple juice by 3 log cycles. (1996) observed that a PEF treatment at 40 kV/cm reduced the number of S. coli O157:H7 and Salmonella food borne illness, associated with consumption of contaminated, unpasteurized apple juice, have caused much concern about the safety of the product as it is currently marketed ( Besser et al., 1993 Steele et al., 1982). More recently, preservatives such as potassium sorbate and sodium benzoate have been employed. Juice producers have traditionally relied upon the acidity of the juice and refrigerated storage for preservation of the product. Pasteurization is believed by many to adversely affect the flavor and aroma. Much of the appeal of apple juice is due to its fresh apple flavor and aroma as well as to its full-bodied texture. They are also often available in areas of the country where apples are not traditionally grown.
Recent advancement in production and marketing have made year-round consumption of these beverages possible. They are the traditional fall beverages in many parts of the country. Barbosa-Cánovas, in Food Preservation by Pulsed Electric Fields, 2007 Apple juiceĪpple juice and apple cider have been produced and consumed in most of the apple-producing regions of the United States for many years.
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