| 摘要 |
1,077,868. Photo-electric meat testing. SAUNDERS ROE & NUCLEAR ENTERPRISES Ltd. April 4, 1966, No.14944/66. Heading G1A The fat to lean meat ratio of a meat product, e.g. sausage meat, is tested by passingγ- radiation from a promethium-147 bremsstrahlung source through the product and obtaining a count of the radiation transmitted, this count being compared with that obtained, using a standard filter of a material other than the product, and equivalent to an acceptable fat to lean meat ratio for the product. The apparatus used comprises a holder 7, for the source 8 (promethium with an aluminium or zirconium target) mounted on a turn-table 3 within shielding 2. The sample 16 can be moved to locate it underneath the detector, a Geiger-Muller chamber 18, whose pulse output is counted by a counter 22, controlled by count selector 23, timer 24, start control 25 and reset 26. The standard filter is of aluminium, for example, and its thickness is decided by comparing the count time obtained with filters of different thicknesses with the count time obtained using a predetermined quantity of meat of satisfactory fat to lean meat ratio. In this calibration, five counts were taken for the sample each filter and the average times compared. An unknown sample of sausage meat can thus be tested by comparison with this standard filter, the quantity of meat used being the same as that used in the calibration. If the difference in the counts is outside the permissible circuits, the fat to lean ratio is unsatisfactory. The method relies on the high absorption by lean meat over that by fat due to differences in the atomic numbers of the elements contained therein, and so the presence of other ingredients in the meat may decrease the sensitivity of the method. |
