Irradiation inactivation of four Salmonella serotypes in orange juices with various turbidities

Reconstituted orange juice inoculated with Salmonella Anatum, Salmonella In fantis, Salmonella Newport, or Salmonella Stanley was treated with gamma ra diation at 2 degreesC. To determine the relationship between juice antioxid ant power and D gamma (dose required to achieve 90% mortality), juice solid s were removed prior to inoculation by centrifugation and/or filtration to create juice preparations of varying turbidity. Ln unadulterated orange jui ce, Salmonella Anatum (D-gamma = 0.71 kGy) was significantly more resistant than the other species tested. Salmonella Newport (D gamma = 0.48 kGy) and Salmonella Infantis (D gamma = 0.35 kGy) were significantly different, whi le Salmonella Stanley (D gamma = 0.38 kCy) was intermediate between the two . Neither the resistance of each isolate nor the pattern of relative resist ance among isolates was altered in reduced turbidity juice preparations. Al though total antioxidant power was associated with the level of juice solid s resuspended in phosphate buffer, antioxidant power was not significantly associated with turbidity in the juice preparations or with D, of any speci es. The variable resistance to irradiation of the Salmonella isolates sugge sts this as a more significant factor than turbidity or antioxidant power i n designing antimicrobial juice irradiation protocols.