INFLUENCE OF TEMPERATURE AND MODIFIED ATMOSPHERE ON THE MICROBIAL PROFILE OF PACKED GEMLIK DRY‐SALTED OLIVES

Abstract

ABSTRACTThe effect of a chlorine wash on microbial growth in packed (vacuum and MAP), dry‐salted olives of the Gemlik variety stored at 4C and 20C was studied for 7 months. The study was based on microbiological changes occurring in dry‐salted olive samples during their shelf life. The microbiota were comprised of total viable bacteria, LAB and yeasts, mold, Enterobacteria and Pseudomonads. At 4 and 20C, the population of yeasts increased steadily in control samples during the shelf‐life period (with and without chlorine exposure). At 20C, neither of the packaging methods was effective in suppressing total viable and LAB growth. The count of TYM increased in the MAP samples after the third month at 20C; therefore, different combinations of chlorine and CO2 and N2 (or combinations of chlorine with only CO2 or N2) can be used to control yeast–mold growth. The combination of a 35% CO2 and 65% N2 (with a 10‐ppm chlorine wash) at 4C was the most effective at controlling the growth of total viable, LAB and TYM. No Enterobacteria and Pseudomonads were detected since the high salt content is not favorable for their growth.PRACTICAL APPLICATIONSMAP has been used for several years for preserving fresh fruits and vegetables. The use of MAP for the storage of fruits and vegetables at a low temperature is more effective than vacuum packaging alone for preventing the growth of microorganisms due to its bacteriostatic effects. Better results can be obtained if MAP is supported with a low‐concentration antimicrobial agent (chlorine). In future research, combinations of CO2 and N2 at various concentrations in the packaging should be evaluated to determine their ability to increase microbiological quality, especially to control yeast–mold growth in packaged olives.