Matrix-assisted laser desorption/ionization time-of-flight mass spectrometr
y (MALDI-TOF MS) was used to determine the fate of nisin in meat products.
Nisin in 0.02N HCl was added to fresh and cooked meat and meat juice and sa
mples were stored at 4 degrees C overnight. Residual nisin solutions and me
at juice and meat extract supernatants were analyzed for antimicrobial acti
vity and for nisin. Nisin was recovered from cooked meat extract and cooked
meat juice; however, only nisin bound to a food component was detected in
fresh meat extract. Mass spectra for raw meat and juice showed a signal 307
Da greater than the mass of nisin. Results indicated that nisin was likely
inactivated in raw meat by an enzymatic reaction with glutathione.