Use of MRI and P-31 NMR for detection of bone and other foreign objects within meat

Danielle D. (Rellinger) Bellmer, Purdue University

Abstract

Concern for the safety and quality of food products has been continuously increasing. The meat industry has been particularly concerned with the presence of foreign objects in meat products. Preliminary studies involving the use of MRI for detection of foreign objects demonstrated that objects could be easily distinguished from the meat. However, the objects were indistinguishable from air pockets within the meat, limiting detection to the size of the void spaces within the sample. For detection of bone specifically, phosphorus ($\sp{31}$P) NMR was investigated. In a 4.7 Tesla magnet system, bone and meat were determined to have linewidths of 2.14 kHz and 54 Hz, respectively, making their respective T2 times very different. Samples containing both meat and bone were modeled with a two-component exponential decay model in the time domain, utilizing their differences in T2 times. A linear relationship was developed between bone mass and bone signal amplitude fit with the two-component model for each of a number of different scan and delay configurations. The slope of the curve for each scan and delay configuration was calculated to determine which method showed the greatest change in signal per unit bone mass. Larger numbers of scans and longer delay times had the steepest slopes, with a 64 scan, 10 sec delay configuration being the best. The 95% confidence intervals around each mg of bone mass were calculated, and the smallest detectable bone fragment was determined to be the lowest bone mass size with a confidence interval that did not overlap the interval for the zero bone mass. In the 4.7 Tesla magnet, using 16 scans and a 10 s delay time, the smallest detectable bone chip has a mass of 4 mg.

Degree

Ph.D.

Advisors

Morgan, Purdue University.

Subject Area

Agricultural engineering|Food science

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