Effects of Microwave Radiation, Organic Acid and Salt Combination on Survival of Pseudomonas Aeruginosa Inoculated in Veal Meat Stored in Refrigerator

Introduction:various species of pseudomonas are abundantly found in the environment. although they are weak pathogens, these bacteria play a key role in food hygiene and human health as they are psychrotrophic bacteria and could grow and proliferate at refrigerated temperatures, producing proteolytic and lipolytic enzymes. the present study aimed to evaluate the effects of microwave radiation, organic acid, and salt combination on the survival of pseudomonas aeruginosa inoculated in veal meat in refrigerated storage. methods: the simultaneous effects of various doses of microwave radiation and various concentrations of salt and lactic acid on p.aeruginosa inoculated onto veal meat were assessed. in total, 108 samples were evaluated in nine treatments on days zero, three, six, nine, 12, and 15 during chilled storage at the temperature of -4⁰c. the control group was treated with distilled water. the bacterial count was determined in pseudomonas agar medium, which indicated that various concentrations of acid and salt, as well as different microwave exposure times and their interactions, had significant effects on the mean logarithm number of bacteria during the refrigeration period. data analysis was performed in spss version 21 using the mixed repeated measures anova. results: the interactions between microwave radiation, organic acid, and salt caused further reduction in the bacteria count compared to the control group. a significant difference was observed in the bacterial count in the acid and salt treatments with the control group (p<0.001). the effects of the salt concentration and microwave duration were controlled using 2.5% and 5% lactic acid, which reduce the bacterial logarithm during the refrigeration period compared to the acid-free samples (p<0.001). in addition, 5% acid significantly decreased the bacterial count logarithm during the refrigeration period compared to the samples treated with 2.5% acid (p<0.001). by controlling the effects of acid concentration and microwave duration, use of 4% and 6% salt significantly decreased the bacterial count logarithm during the refrigeration period compared to the non-salt samples (p<0.001). on the other hand, the samples containing 6% and 4% salt had no significant difference in terms of the bacterial count logarithm during the refrigeration period (p=0.89). the microwave duration of nine seconds (65°c) could significantly decrease the bacterial logarithm compared to seven (55°c), five (45°c), and three seconds (30°c) (p<0.001). moreover, use of lactic acid (5%) and salt (6%) caused the microwave duration to reduce from nine seconds (65°c) to five seconds (45°c) to complete the elimination of bacteria. conclusion: according to the results, use of organic acid, salt, and microwave irradiation for p. aeruginosa inoculated into meat during refrigerated storage reduced the bacterial count. furthermore, the combination of microwave radiation, organic acid, and salt concentration decreased the bacterial count more significantly compared to the control group, and a significant difference was observed between the bacterial counts when each factor was used compared to the control group.