Microbiological and Related changes during fermentation of Poultry waste

Fermentation has centuries of` history of achievement without theoretical foundation. Fermentation preserved food through the accumulation of lactic acid in the preparation of cheese, soured milk, sauerkraut and also ensilage. It was Pasteur's demonstration on the role of microbes, that led to his definition of fermentation as "life without air". As Pasteur correctly recognized that in fermentation, the organisms derive metabolic energy by its property of performing its respiratory function,somehow or other, with the oxygen existing combined in sugar. Superficially it might seem that microorganisms are generally harmful but this is far from the truth. Their tremendous benefits offered to man greatly outweigh their harmful effects. Not only are microbial activities essential in recycling nutrients and energy, but also microbial techniques are applied commercially to provide foods,beverages, pharmaceutical products, chemicals and even feed. Throughout history man has utilized microorganisms. But only during the last century he began to learn about the organisms involved. Continued research and increased understanding of microbial activities undoubtedly has led to various benefits. It is very important that one controls the undesirable microorganisms so that the desirable useful bacteria (which are most wanted) will be provided the best of favorable conditions and nutrition. The desirable microorganisms dominate, so that a pure, uncontaminated product can be obtained. Likewise in fermentation the selection of specific microorganism is necessary to derive a particular product. This necessitates understanding and applying the principles of microbial growth and physiology. The term fermentation is correctly employed to describe the breakdown of carbohydrates and other materials under anaerobic conditions where primary interest is in describing the end rather than the mechanisms of biochemical reactions. Silage is a process in material that undergoes fermentation where in bacteria produce lactic acid, acetic acid and butyric acid from sugar present in the raw material. The net result is reduction in pH which prevents the growth of spoilage microorganisms. The efficiency of silage is judged according to the relative proportions of the acids produced during fermentation. The greater the proportion of lactic acid to butyric acid the higher is the efficiency. A good quality silage is one which is favoured by the lactics-producing lactic acid, while one with butyric acid is referred to as silage of poor quality. Many reports have appeared on the understanding of silage processes as affected by environmental factors. The effects of these factors on microbial succession are yet to be understood during fermentation. The ensilage technique has also been applied for the preservation of fish and fish wastes (Woolford, 1984). It appears that fermentation process was mainly due to homofermentative bacteria in fish and fish waste silage. It is also observed that there is much variation in the type of fermentation from one silage fermentation to another (Woolford. 1984). The significant bacteria in silage fermentation are: Lactic acid bacteria, Endospore forming bacteria. Coliform bacteria and the fungi. These groups could be further classified as spoilage, pathogenic and acid producers. The pathogenic microorganisms are the Pseudomonas and fungi. The acid producer mainly is lactic acid bacteria. Yeasts may also contribute to the production of acids. Fermentation silage has become an important method of preservation of waste materials. Since the poultry industry has enormously expanded in recent years in India, large quantities of waste material such as poultry viscera are generated. These wastes cause environmental pollution and health hazards. This waste material contains large quantities of proteinaceous material. It is therefore necessary to conserve this waste material for useful purposes. Thus an economical and simple process such as fermentation silage process may be a very useful method for preserving poultry intestine, especially in tropical countries like India. There is no available data and information on the type of fermentation (homofermentative and heterofermentative)taking place in the poultry viscera. Therefore attempts have been made in the present investigation to understand the microorganisms involved in the ensilage of poultry intestine, their interactions with each other, their behaviour towards environmental variables, within the ensiled environment, and their usefulness in preserving the proteinaceous material like poultry intestine.