Non-destructive evaluation of ATP content and plate count on pork meat surface by fluorescence spectroscopy

The potential of fluorescence spectroscopy was investigated for the non-destructive evaluation of ATP content and plate count on pork meat surface stored aerobically at 15 °C during three days. Excitation (Ex) Emission (Em) Matrix of fluorescence intensity was obtained and fluorescence from tryptophan (Ex = 295 nm and Em = 335 nm) and NADPH (Ex = 335 nm and Em = 450 nm) was detected. Because tryptophan and NADPH fluorescence changed along with the growth of microorganisms, microbial spoilage on meat could be detected from fluorescence. By applying PLSR (Partial Least Squares Regression) analysis, ATP content and plate count were predicted with good determination coefficient (0.94-0.97 in calibration and 0.84-0.88 in validation).

► Plate count and ATP content were predicted from fluorescence intensity by PLSR. ► ATP content was proved to be a parameter of microbial spoilage. ► Fluorescence from tryptophan and NADPH was detected on pork meat surface. ► Tryptophan decreased with time because of degradation of tryptophan by bacteria. ► NADPH increased with time because bacteria produced it in HMP pathway.