Microbiological quality of chicken breast meat after application of thyme and caraway essential oils

The aim of the present study was to evaluate the effect of selected types of antimicrobial essential oils to the various groups of microorganisms during storage of chicken meat. The samples of chicken breast meat were used in the experiment. The number of lactobacilli, Pseudomonas spp., anaerobic plate count and Enterobacteriaceae after application of caraway and thyme essential oils (EO) at concentration 1% v/w in a combination with the ethylenediaminetetraacetate (EDTA) solution 1.5% w/w and vacuum packaging were evaluated. The samples were analyzed at 0, 4th, 8th, 12th and 16th day of storage of chicken meat at temperature 4 °C. Another aim was to determine the species of isolated microorganisms from samples of chicken meat by MALDI-TOF MS Biotyper (matrix assisted laser desorption ionization-time of flight mass spectrometry). The number of Lactobalillus spp. ranged from 1.35 log CFU.g-1 in all groups to 3.04 log CFU.g-1 on 0th day to 3.04 log CFU.g-1 on 4th day in control group stored in air. The Pseudomonas spp. was not found in all tested samples at the start of the experiment, the highest number of Pseudomonas spp. was in the control group on 16th day (2.68 log CFU.g-1). Presence of Pseudomonas spp. were not found during storage in groups after treatment with caraway and thyme EO. The values of anaerobic plate count ranged from 2.81 log CFU.g-1 on 4th day in control group with vacuum packaging to 5.19 log CFU.g-1 on 16th day in control group in air condition. The Enterobacteriaceae was not found in all tested samples on 0th day and ranged to 4.46 log CFU.g-1 on 12th day in control group in air condition. From Lactobacillus spp., the most often identified species was Lactobacillus paracasei, from genus Pseudomonas, there were identified Pseudomonas fluorescens in two cases. From anaerobic plate count, there were isolated Staphylococcus warneri from control goup stored in air condition, Kocuria rhizophila from control group with vacuum packaging, Staphylococcus warneri, Aeromonas salmonicida and Aeromonas popoffii from control group treated with EDTA, Staphylococcus hominis and Staphylococcus epidermidis from group treated with caraway essential oil.  From Enterobacteriaceae, the most bacteria were isolated from control group in air condition and from control group treated with EDTA.