Application of the elusieve process to the classification of meat and bone meal particles

Authors: Garcia, Rafael; Piazza, George

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2014
Publication Date: 1/15/2015
Publication URL: https://handle.nal.usda.gov/10113/60634
Citation: Garcia, R.A., Piazza, G.J. 2015. Application of the elusieve process to the classification of meat and bone meal particles. Applied Engineering in Agriculture. 31(1):165-170. DOI: 10.13031/aea.31.10410.

Interpretive Summary: Meat and bone meal (MBM) is a substance that is produced using the leftover material from the processing of animal carcasses into meat products. It consists of small granules; some of these granules are bone particles, and some are cooked pieces of soft tissue. The soft tissue particles have a much greater protein content than the bone particles. MBM could be more valuable and useful if the bone particles could be separated from the soft tissue particles. This research report describes a particle classification system that has been used successfully with plant products such as grain, and an attempt to use this system to classify MBM particles. The system involves using a series of sieves to separate MBM particles by size. Then, each of the MBM size fractions is separately passed through a machine that separates particles by having them fall through a stream of blowing air. The result of processing with this system is shown to be two fractions of MBM, one of which has significantly increased protein content, and one which is rich in bone particles and low in protein. These separation results are better than what has been achieved previously. Limitations of this system for industrial use are also discussed.

Technical Abstract: Meat and bone meal (MBM), a product of the rendering industry, comprises a mixture of two particle types. The utility and value of MBM would increase if the two particle types could be separated economically. Past efforts at classification of MBM particles have achieved limited success. In the present research, a classification method originally developed for distiller’s dried grains is applied with modifications to MBM. In this process, known in the literature as elusieving, a mixture of particles is screened into multiple fractions, and each fraction is processed separately using air classification units. In the present research, the MBM was treated with an anti-caking agent prior to processing. The screen opening sizes were chosen to isolate the smallest particles, which are very high in ash, and divide the remaining material into thirds. Each fraction was run through an air classification unit at multiple airspeeds, and the proximate compositions of the materials collected from the units were determined. These results were used to determine the optimal separation of particle types that would be achieved if each fraction were classified at the ideal airspeed. These results are shown to be superior to the separation achievable through screening or air stream classification alone. The appropriateness and limitations of the elusieve process for classifying MBM particles are discussed.