Microbial analysis of on-site compost made from meat by-products at Sunnyside Meats In Durango, Colorado

Abstract

Composting of different substrates from different environments has been studied in great detail. Composting is the biodegradation of organic material into matured, stable humus in which microorganisms play an important role. The process is important for the cycling of elements, the removal and treatment of unwanted wastes and the prevention of disease. The microbial community responsible for the decomposition of any organic material is a complex mix of organisms from all three domains of life—Bacteria, Archaea and Eucarya. Microbiota found in a compost mix are a blend of organisms that can thrive under different conditions; wet to dry; cold to hot; low pH to high pH, etc. Thermophiles that can thrive in high temperature zones in a compost pile can drive the composting process. This research investigated an on-site composting of meat by-products at Sunnyside Meats, a local meat processing facility in Durango, Colorado. This experimental, pilot-scale composting system was initiated with slaughterhouse wastes, wood chips and Sudan grass, ground together, mixed, aerated and given time for microbiota to digest the organic material to composted humus. The simple design and construction of this compost addressed the safety regulations put forward by the U.S. Department of Agriculture (USDA) whose on-site inspectors aided in the oversight of the experiment and its compliance with slaughterhouse operation. The primary objective of the study was to analyze the microbial risks associated with composting of animal wastes. Samples for microbial identification were taken from both pre-composting units and aerated compost bin. With a DNA sequence-based, molecular microbial community analysis approach, a wide variety of possible pathogens were identified at the different locations of the composting unit, but the research confirmed that this method of composting helps in the reduction of survival and occurrence of pathogens. Some of the pathogens identified belong to the Phylum Actinobacteria, Bacteroidetes, Proteobacteria and Firmciutes. The results also indicate that the on-site composting of slaughterhouse wastes is a viable option for the treatment of slaughterhouse waste and prevents the deposition of this organic material into landfills, while returning nutrients to the Earth in the form of rich humus that can be deposited on to agricultural fields as an organic fertilizer.