Investigating the antimicrobial properties of edible film of polylactic acid-Iranian tragacanth gum along with the essential oil of Zygophyllum eichwaldi on the microbial spoilage of ostrich thigh meat at refrigerator temperature

The present study was conducted with the aim of investigating the effects of PLA- Iranian tragacanth gum composite film with Zygophyllum eichwaldi essential oil on the microbial characteristics of ostrich thigh meat stored at 4°C. For this purpose, first, 5 film treatments including: PLA, PLA+ gum and PLA+ gum with concentrations of 0.5%, 1.5% and 1.5% essential oil to determine the microbial properties of the film and then the effect of the mentioned films along with the control treatment (without film) was evaluated on the microbial factor (total bacterial count, psychrophilic bacteria, Enterobacteriaceae and lactic acid) in the ostrich fillet samples tested on days 0, 4, 8, 12 and 16 and the resulting data were SPSS software was analyzed. According to the results, adding essential oil to the film increased the antimicrobial activity of the films, and with increasing concentration, better results were observed (P<0.05) and the antimicrobial activity against gram-positive bacteria was higher than gram-negative bacteria. The results of the second part of this study showed that the samples packed with composite films containing essential oil showed lower (P<0.05) microbial changes than the control samples without essential oil during the study, and the film containing 0.5 and 1% of essential oil had the best effects compared to other groups (P<0.05). Therefore, the use of PLA- Iranian tragacanth gum film containing Zygophyllum eichwaldi essential oil in the packaging of ostrich meat has a very favorable effect in controlling the microbial characteristics effective in meat spoilage and increases its shelf life.