The literature is reviewed to provide the latest information on the development of pit manure products for the control of odor from manure. Problems that are currently being encountered in product designing and testing are presented. As the manure odor is composed of many different volatile organic compounds characterization is complicated. In past research, specific volatile acids have been identified as malodor indicators, however in recent studies, results show that such association may be misleading. An in-depth classification of the odorous compounds considering their inherent characteristics is needed. This lack of information on odours and odours compounds have contributed to the blind development of pit additive products and the fact that no a standard procedure for odour has been developed to scientifically evaluate pit additive products has restrain the development of knowledge on odour control by additives.
This publication is very interesting because it covers most of the work done on odor characterization of the odor compounds and also on the odor evaluation techniques.