EFFECT OF MICROWAVE EXPOSURE COMPARED WITH CONVENTIONAL HEAT TREATMENTS ON Escherichia coli O157:H7 AND Salmonella typhimurium IN CHICKEN BURGER AND MEAT SAUSAGE

       Escherichia coli O157:H7 and Salmonella typhimurium  are two of  the most important foodborne  pathogens causing  gastroenteritis all around the world . Two samples  were taken from chicken burger and meat sausage  samples ,which prepared in  a manner similar to commercial one . Then, samples  inoculated with approximately10⁶-10⁷cfu/gof E. coli O157:H7 and10⁷-10⁸cfu/g of S. typhimurium  then, cooked by microwaving , grilling , frying and boiling . Following exposures to heat treatments, viable counts and temperature measurements were immediately performed.
          Elimination of E. coliO157:H7 inoculated onto chicken burger was observed after microwaving, grilling, frying and boiling exposure for 40 sec., 7 min., 2.5 min. and 1.5min. , respectively and  after  35 sec., 8 min., 2 min., and 2 min., for meat sausage samples, respectively.
      S. typhimurium inoculated onto chicken burger was undetectable after  microwaving, grilling, frying and boiling for  35 sec., 7 min., 1.5 min.  and 1.2 min., respectively, and  after 30 sec., 6 min., 1.5 min., and 1min.,  for meat sausage samples, respectively . This study showed that the lowest temperature degree at which elimination of E. coli O157:H7 was realized  by microwave heating at 74°C for 40sec. and 66.6°C for 35sec. for both chicken burger and meat  sausage. As for
S. typhimurium, it was 65°C for 35 and 30 sec. for both chicken burger and meat  sausage samples, respectively.
This study also showed that E. coliO157:H7 was more heat resistant than S. typhimurium under the same conditions.