Determination of the protective effects of carvacrol, thymol and cuminaldehyde when used individually and in combination as natural antimicrobials in ground meat samples contaminated wi̇th E. coli ATCC 25922

In the current study, the antimicrobial effects of nanoemulsions of thymol, carvacrol and cuminaldehyde, which have the potential to be used as natural antimicrobials on foods, were examined on fresh red meat (minced meat) contaminated with Escherichia coli ATCC 25922 microorganism. For this purpose, an experimental plan was made using the Response Surface Method Box-Behnken Design and five central points for four factors (carvacrol, thymol, cuminaldehyde concentrations and storage day). Antimicrobials at the doses determined in the experimental design were added to raw ground meat previously inoculated with Escherichia coli ATCC 25922 and tested to determine the number of live microorganisms on the 1st, 15th and 29th days under refrigerator conditions (+4 °C). As a result of the experiment, it was determined that carvacrol and Thymol were effective against the E. coli ATCC 25922 strain found in ground meat, while cuminaldehyde was ineffective. Additionally, storage time was found to be effective on the activity of E. coli ATCC:25922. It was determined that the data conformed to the linear model. When we look at the antimicrobials (carvacrol, thymol) that showed maximum reduction in the analysis results, it was concluded that the total of these antimicrobials should be 3750 ppm in order to achieve a 3 log or more reduction on the target microorganism (E. coli ATCC 25922). In addition, in the optimization, the optimum conditions for the targeted microbial reduction (5 logs) were found to be 2158.2 ppm for carvacrol concentration, 2227.95 ppm for thymol, negligible for cumin aldehyde, and 22 storage days. While a theoretical decrease of 4.97 was predicted under these conditions, verification experiments showed that this value was a decrease of 5.22±1.32 log level. At the same time, the compatibility result of the model under optimum conditions resulted in an error of 5%, and it was determined that the model and experimental results were compatible. The target was achieved on the 22nd day (37 °C), proving the validity of the model.