Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2005
Publication Date: July 20, 2005
Citation: Fan, X., Sokorai, K.J., Sommers, C.H., Niemira, B.A., Mattheis, J.P. 2005. Effects of calcium ascorbate, an antioxidant and antibrowning agent, on radiation resistance of l. monocytogenes and quality of "gala" apple slices. Institute of Food Technologists Annual Meeting, July 16-20, 2004, New Orleans, LA. p. 36E-31. Technical Abstract: Ionizing radiation exerts its effect mainly through the free radicals generated from radiolysis of water. Antioxidants may scavenge the radicals, negating or reducing the impact of irradiation on pathogen inactivation and on product quality. This study was conducted to evaluate the impact of calcium ascorbate (CaA, an antioxidant and antibrowning agent) on the radiation resistance of L. monocytogenes inoculated into CaA solutions and on apple slices, and to investigate the effects of irradiation and CaA on quality of 'Gala' apple slices. The radiation resistance of L. monocytogenes artificially inoculated in 0, 3.5 and 7% CaA solutions and on apple slices that had been treated with the three levels of CaA were analyzed. Non-inoculated apple slices treated with 0, 3.5%, and 7.0% CaA were exposed to 1.6 kGy gamma radiation (a dose equivalent to at least 5-log reduction in L. monocytogenes). Quality was analyzed during 14 days of modified atmosphere storage at 4°C. Results showed that CaA significantly increased radiation resistance of the pathogen both in solution and on apple slices. CaA at levels of both 3.5 and 7.0% prevented the browning of the apple slices. The apple aroma intensity, however, decreased as the concentrations of CaA increased. Irradiation at 1.6 kGy did not significantly affect color, soluble solid content, titratable acidity, or apple aroma intensity. The only negative effect of irradiation on apple slices appeared to be a loss of firmness. However, firmness of irradiated samples treated with 3.5 or 7.0% CaA was always similar compared to the non-irradiated samples that were not treated with CaA. CaA protected L. monocytonenes from radiation both in solution and on apple slices, but radiation at doses sufficient to inactivate a 5-log of the bacterium did not have a significant influence on product quality attributes except the loss in firmness.