A real-time method that rapidly tests meat for spoilage uses a spectroscope to measure compounds produced by microorganisms on the meat.
Researchers from the University of Wales present this new methodology in the June 2002 issue of the journal Applied and Environmental Microbiology.
The process, called fourier transform infrared spectroscopy (FT-IR), uses infrared light waves to identify specific organic compounds within the meat. The technique measures the absorption of various wavelengths of infrared light by the meat. The pattern of absorption creates a unique fingerprint for each compound.
In the study, the researchers tested the ability of FT-IR to detect the biochemical byproducts of microbial contamination in chicken breasts left at room temperature to spoil.
Every hour, FT-IR measurements were taken directly from the meat surface and microbial counts were taken by standard culture methods. Estimates made from FT-IR in less than 60 seconds were similar to the final counts made by culturing.
"Using FT-IR, we were able to acquire a metabolic snapshot and quantify, non-invasively, the microbial loads of food samples accurately and rapidly (within 60 seconds) directly from the sample surface," say the researchers.
(Reference: D.I. Ellis, D. Broadhurst, D.B. Kell, J.J. Rowland and R. Goodacre. 2002. Rapid and quantitative detection of the microbial spoilage of meat by fourier transform infrared spectroscopy and machine learning. Applied and Environmental Microbiology, 68: 2822-2828.)