Effect of wavelength on spatial measurements of light scattering for the measurement of pork quality.

White light from a xenon arc was focused onto the upper surface of 25-mm-thick transverse sections of pork longissimus muscle. A servo motor moved an optical fiber across the lower surface of the muscle to collect transmitted light, which then was passed through a grating monochromator and onto a photomultiplier for spatial measurements of scattering (SMS) and transmittance spectra. The SMS were calculated as the slope of the logarithm of transmittance relative to path length through the sample (which was calculated trigonometrically). Pale, soft, exudative (PSE) pork was measured with an index that included a subjective evaluation of meat color and objective measurements of reflectance, drip loss, and centrifugation fluid loss. The strongest correlation of SMS with PSE was at 610 nm (r = .86, P less than .005) and the strongest correlation of transmittance with PSE was at 650 nm (r = -.95, P less than .005). This supports the use of a red laser at 633 nm for the detection of PSE pork.