Effect of Poultry Layer and Cow Manure Composting on Dynamic Population of Escherichia coli Migula and Salmonella spp.

Abstract

The research was aimed to reduce contamination and factors affecting dynamic population of Escherichia coli and Salmonella spp. Composting was compared with the non composting of poultry layer and cow feces. The experiment was conducted in RCB design with 3 replications at Mae Hia Agricultural Research Station and Training Centre during June to October 2009. Windrow system was used in the composting of manures. The compost heaps were maintained with humidity at 60-70% and regularly turning over every 15 days. The non composting materials were packed in the plastic bugs (used fertilizer sacks). All treatments were periodically sampled at 1, 3, 5, 7, 14, 21, 28, 42, 56, 70, 84, 98, 112, 126 and 140 days for determination of dynamic microbial population, chemical analysis of the materials and calculation of correlation efficient between microbial population changing and analyzed factors. E. coli in composting cow manure were significant continuously decreased until completely disappeared after 84 days of composting. On the other hand, those in non composting wee slowly decreased from 6.4 to 4.69 log MPN/g from the beginning to the end of experiment. In poultry layer manure, the E. coli were completely disappeared after 70 days of composting. Contrast with cow manure E. coli in the non composting poultry layer was slightly increased from 2.78 to 4.02 log MPN/g. For Salmonella spp., it was not found in poultry layer manure and cow manure when were composted for 56 and 98 days, respectively. However, Salmonella spp. Was contaminated both in poultry layer and cow faces which were not composted. The decreasing of both microbial population was singnificantly correlated with the changing of C:N, EC, %OM, pH and temperature in composted poultry layer and cow manure. Nevertheless, the contaminated microbes in non composted cow faces were correlated with only C:N and the temperature, whereas the correlation was not found in the non composting poultry layer.