3. Results and discussion
3.1. Chemical and physical properties of frankfurters
The cooking yield of the two replicates of frankfurters was 91.5±
1.2%. Thewater activity and pH of the frankfurters after inoculationwas0.980±0.002 and 6.06±0.12, respectively. The pH values of frankfurters
were significantly (Pb0.05) affected by immersing in salad
dressings due to the acid ingredients (data not shown in tabular
form). On day-0, without prior microwave heating, immersion in oils
with lemon juice or vinegar for 5 min reduced the pH of samples,
compared to the control (pH6.06), by 0.17–0.18 (P≥0.05) and 0.25–0.27
(Pb0.05), respectively, while greater reductions (Pb0.05) of 0.29–0.43
were obtained for samples dipped in the four commercial salad
dressings. Similarly, reduced pH values were found in samples treated
by most salad dressings for 20 min, and the lowest (Pb0.05) pH (5.46)
was observed in frankfurters treated with Vinaigrette. The pH values of
the samples did not show large variation (P≥0.05) when exposed to
microwave heating and between storage times. Beuchat et al. (2006)
reported that the main factor in salad dressings causing death to
pathogenic bacteria is the low pH.