Abstract Meat is one of the most perishable food items, whose microbial spoilage, in addition to increasing the waste of this expensive food item, causes the death of many people every year. One of the ways to protect and increase the shelf life of food, including meat, is to use active packaging with antimicrobial properties. The purpose of this research was to investigate the effect of modifying the surface of meat packages by non-thermal plasma on inhibiting the growth of microorganisms. In this research, two indicator bacteria, Staphylococcus aureus and Escherichia coli, were used. For this purpose, at first, in order to find the optimal treatment, the polystyrene containers used in meat packaging were cut into dimensions of 3x3 cm and treated with plasma at voltages of 18 and 20 kV for 10, 15 and 30 minutes. They were treated for minutes. Then the surface treated with plasma was brought into contact with the desired bacteria, and after the incubation period, these bacteria were cultured and counted. The reduction of the microbial load over a period of 7 days was investigated and compared with the control sample. The results showed that the treated containers were able to reduce the microbial load by one logarithmic cycle compared to the control sample. In order to investigate the effect of plasma surface on the reduction of microbial load, the target bacteria were examined by scanning electron microscope and surface damage was clearly seen in them. Also, the eva‎luation of Fourier transform infrared spectroscopy showed that the functional groups on the surface of the polystyrene container changed under the influence of plasma. An increase in the hydrophilicity of the closed polymer surface and an increase in the crystalline structure were among the other changes observed in the characteristics of the container. Since the greatest decrease in microbial load was related to the sample treated with voltage 20 and duration 30 minutes, as a result, this treatment was selected as the optimal treatment. Next, the longissimus dorsi muscle of the calf was packed in plasma containers with optimal treatment and its microbial load was eva‎luated compared to the control sample during 7 days of storage in a refrigerator at 4 degrees Celsius. The results showed that the samples whose containers were treated with plasma were able to reduce the microbial load by more than one logarithmic cycle compared to the control sample. Color, pH and meat texture factors were measured in the treated samples and compared with the control sample. The results showed that the use of plasma-treated packages, in addition to increasing the shelf life of meat, were able to maintain its quality characteristics, including color, texture, and pH, for a longer period of time. According to what has been mentioned, it can be concluded that packaging with plasma treated containers can be used as an antimicrobial packaging to increase the shelf life of food such as meat.

صبيحه سليمانيان زاد , نفيسه سلطاني زاده

عباس پاكدل , مريم فنائي