Purpose: The aim of this work was to investigate the feasibility of FTIR spectroscopy to quantify biochemical changes in fresh, minced pork meat in the attempt to monitor spoilage.
Methods: Minced pork meat was stored under modified atmospheres (40% CO2:30% O2:30% N2) at 0, 5, 10, and 15 °C, and samples were withdrawn to undergo microbiological, sensory and FTIR analysis. Partial least squares (PLS) models were constructed to correlate spectral data with meat spoilage in order to classify meat in 3 predefined sensory classes (fresh, semi fresh and spoiled). Moreover, PLS regression (PLS-R) models were developed to correlate the population dynamics of the microbial association with FTIR spectral data. The performance of the models was based on graphical plots and statistical indices.
Results: Results demonstrated good performance in classifying meat samples in the predefined sensory classes with overall correct classification of almost 81.8% (sensitivity within the classes: 87.5%, 55.3%, and 97.1% for fresh, semi-fresh, and spoiled, respectively). For PLS-R models, the values of the bias factor were close to unity for all microbial groups, indicating no systematic bias, while the calculated values of the accuracy factor showed that the average deviation between predictions and observations was 6.0% and 5.9% for total viable counts and Pseudomonas spp. and 8.7% and 10.5% for B. thermosphacta and lactic acid bacteria, respectively. Finally, correlations within 0.75-0.83 were calculated for all microbial groups with the exception of Pseudomonas spp. where the respective value was lower (0.65).
Significance: FTIR could become an interesting tool to monitor minced pork spoilage through the measurement of biochemical changes occurring in the meat substrate.
The authors acknowledge the Symbiosis-EU (www.symbiosis-eu.net) project.