This research investigated the effect of antibacterial activity of Guava leaves extract. Antibacterial activity was determined by agar well diffusion method and test with Staphylococcus aureus Bacillus cereus and Escherichia coli. The results showed that Guava leaves crude extract best inhibited the growth of Bacillus cereus followed by Staphylococcus aureus and Escherichia coli with a mean inhibition zone was 22.0 ±0.3 19.00 ± 0.2 and 14.5 ± 0.3 mm respectively. When comparison antibacterial activity between Guava leaves extract with ampicillin 0.010 mg.

In this study The paper aims to produce extracts from guava leaves. For use in food packaging. And to test their ability to inhibit bacteria. Staphylococcus aureus paper extracts from guava leaves. Because the bacteria Staphylococcus aureus to live in the air dust waste water food and milk supplies. The strain also grows well in climates with oxygen. The test extracts from guava leaves. A chemical properties of guava leaf extract has a pH of 5.4 + 0.02 acid content (% citric acid) was 1.2 ± 0.1 and the amount of phenolic total (mg gallic acid / g) levels. 63.1: 1.9 The performance of guava leaf extract in inhibiting bacteria. Staphylococcus aureus by means paper disc diffusion on agar Nutrient agar at 36 ° C for 24 hours diameter clear zone (cm.) Was 1.3 ± 0.5 and tested for the Minimum Inhibitory Concentration (MIC) by Broth Dilution Technique with. equal to 1.56% of extract of guava leaves

A Comparison Efficiency of Cafeteria Wastewater Treatment with EM Produced by Banana Watermelon and Guava Case Study : Rajamangala University of Technology Phra Nakhon Cafeteria ( North Bangkok Campus) has the objective to compare the efficiency of wastewater treatment by using the EM microbe for the Cafeteria that has no waste water treatment system. The treatment solution was leavening agent EM : Molasses : Fruits : Water in the ratio 1 : 1 : 2 : 20 liters (as an experimental group) and leavening agent EM : Molasses : Water in the ratio 1 : 2 : 20 liters (as a control group). respectively and mixed each solution set in wastewater treatment ratio of 1 : 1000 (EM 1 part : wastewater 1000 part) . In the experiment use the 10 liters of wastewater sampling and added the EM microbe solution every 3 days 10 ml per a day and daily for 3 weeks. Collecting the wastewater every 7 day. Parameters in this experiment are BOD COD SS Oil and Grease pH Color and Odor. The comparison showed that the EM made from watermelon can reduce the BOD and SS of wastewater is the best. And adapt the most of pH to pH 7. The EM make from guava can reduce the COD Oil and Grease is the best. The results were in the standards of sewage release of the building type B. In the 1st 2nd and 3rd week the BOD COD SS Oil and Grease and pH from the waste water treatment with EM microbe that make from Banana Watermelon and Guava ( as a Experimental group) and molasses (as a Control group) only are statistically different at the .05 level. By the way the Color and Odor of the waste water analysis before and after treatment with EM microbe 4 species still have yellow color and bad smell.