The antibacterial effect of aqueous garlic and cinnamon extract at five different temperatures (40O C, 60O C, 80O C, 100O C, 120O C) against five multidrug resistant bacterial isolates (2 gram negative and 3 gram positive), including Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, E. Coli and Proteus mirabilis were studied by well diffusion method. The maximum antibacterial effect of aqueous garlic and cinnamon extract of different temperature obtained in Enterococcus faecalis and E. Coli at 60O C (1.041) and in Enterococcus faecalis at 60O C (0.87) respectively. This antibacterial property was applied on preservation of fish. A time dependent antibacterial study was done using the gum acacia coating with garlic and cinnamon paste. It is observed that the microbial load present on the fish was totally reduced on second day. In short, the aqueous garlic and cinnamon extract and pastes show a wide range of antibacterial activity at 40O C to 60O C and satisfy all the criteria for antibacterial agent as compared to antibiotic Gentamicin. These results suggests that garlic and cinnamon can be used as food preservative and thus the use of other chemical preservatives can be minimized, which would be beneficial for environment and consumer health; or a plastic for food preservation can be invented using the antibacterial activity of garlic and cinnamon, the inner wall of the plastic coated with garlic and cinnamon paste.