Efficacy of ultraviolet light for reducing Escherichia coli 0157 : H7 in unpasteurized apple cider

This study examined the efficacy of UV light for reducing Escherichia coli O157:H7 in unpasteurized cider. Cider containing a mixture of acid-resistan t E. coli O157:H7 (6.3 log CFU/ml) was treated using a thin-film UV disinfe ction unit at 254 nm. Dosages ranged from 9,402 to 61,005 mu W-s/cm(2). Tre atment significantly reduced E. coli O157:H7 (P less than or equal to 0.000 1). Mean reduction for all treated samples was 3.81 log CFU/ml. Reduction w as also affected by the level of background microflora in cider. Results in dicate that UV light is effective for reducing this pathogen in cider. Howe ver, with the dosages used in this experiment, additional reduction measure s are necessary to achieve the required 5-log reduction.