Antimicrobial Effects of Hydroalcoholic Extract of Malva sylvestris as a Food Preservative

Due to the resistance of microorganisms to antibacterial agents, efforts are being made by researchers to replace the plant natural substances with antimicrobial properties and lower side effects. The aim of this study was hydro alcoholic extract of malva sylvestris as a food preservative with some microorganisms, which further cause contamination of food products

The present experimental laboratory study was conducted in 2016. Several experiments, such as gel diffusion and MIC and MLC measurements were performed to evaluate the storage properties of nutrients by a number of microorganisms that are more likely to contaminate food with malva sylvestris extract. After preparing the hydro alcoholic extract, it was applied to the culture medium containing tomato juice, grapefruit juice, pineapple juice and wheat flour, which were infected with Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus Niger. Correspondingly, the minimum growth inhibitory concentration and the minimum lethal concentration of extract as well as sodium benzoate were measured on above microorganisms and then the diameter of the growth inhibition zone of extract was compared with standard antibiotics. The collected data were analyzed using descriptive statistical tests, i.e. the average of tables and graphs.

The present study indicated that at concentrations of 1, 2, 4, 8, and 16 mg/mm of the extract, the diameter of the growth inhibition zone for S. aureus is equal to; 6, 12, 15, 18, and 20 respectively but growth aura was observed for E. coli. On the hand  the MIC and MBC  of extract  at concentrations of  1, 2, 4, 8, and 16 against Aspergillus Niger and Candida Albicans was 25, 31, and 125 mg/ml. however, the growth of all microorganisms against sodium benzoate at a concentration of 2 mg / mm was stopped and the diameter of the growth inhibition zone was observed from 20 to 28 mm..

The results indicated that this extract in combination with chemical additives contaminated with S. areus revealed a high retention effect, but substances contaminated with E. coli had no effect on them. Also, this extract had a good effect on foods contaminated with fungi, but compared to sodium benzoate, this extract had less effect on all microorganisms. However, we hope that in the future, with more work being done on this plant can be used as a suitable alternative to food storage instead of chemical additives.