title: Microbial Safety and Shelf Life of UV-C Treated Freshly Squeezed White Grape Juice.
abstract: The effects of UV-C irradiation on the inactivation of Escherichia coli K-12 (ATCC 25253), a surrogate of E. coli O157:H7, and on the shelf life of freshly squeezed turbid white grape juice (FSWGJ) were investigated. FSWGJ samples were processed at 0.90 mL/s for 32 min by circulating 8 times in an annular flow UV system. The UV exposure time was 244 s per cycle. The population of E. coli K-12 was reduced by 5.34 log cycles after exposure to a total UV dosage of 9.92 J/cm(2) (1.24 J/cm(2) per cycle) at 0.90 mL/s flow rate. The microbial shelf life of UV-C treated FSWGJ was extended up to 14 d at 4 °C. UV exposure was not found to alter pH, total soluble solid, and titratable acidity of juice. There was a significant effect (P < 0.05) on turbidity, absorbance coefficient, color, and ascorbic acid content. Furthermore, all physicochemical properties were altered during refrigerated storage. The microbial shelf life of FSWGJ was doubled after UV-C treatment, whereas the quality of juice was adversely affected similarly observed in the control samples.
authors.affiliation: Dept. of Food Engineering, Izmir Inst. of Technology, Urla, Izmir, 35430, Turkey.
authors.forename: Sevcan
authors.initials: S
authors.lastname: Unluturk
authors.affiliation: Dept. of Food Engineering, Izmir Inst. of Technology, Urla, Izmir, 35430, Turkey.
authors.forename: Mehmet R
authors.initials: MR
authors.lastname: Atilgan
mesh_terms: D055598:Chemical Phenomena; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling; D005514:Food Irradiation / Q000379:methods*; D005516:Food Microbiology; D000067030:Fruit and Vegetable Juices / Q000382:microbiology* / Q000528:radiation effects; D014466:Ultraviolet Rays; D027843:Vitis / Q000737:chemistry / Q000382:microbiology*
keywords: food quality; food safety; juice; non-thermal processing; shelf life