A novel flow injection chemiluminescence method for automated and miniaturized determination of phenols in smoked food samples

Determination of p-cresol levels in smoked meat products using QuEChERS method and gas chromatography-mass spectrometry

p-Cresol is known as an environmental chemical contaminant that has toxic effects on humans. However, the presence of p-cresol in smoked foods has been seen as a flavor constituent. The present study had as objective to optimize and validate the QuEChERS method for the determination of p-cresol in beef hamburger, which was chosen as a representative matrix for six smoked meat products. The analysis was performed by gas chromatography coupled with mass spectrometry (GC-MS). The method showed limit of quantification (LOQ) of 40 µg kg^-1, linearity between 40 and 200 µg kg^-1, recovery higher than 70% and relative standard deviation lower than 14%. The proposed method was applied to six different smoked foods and the p-cresol concentration ranged from 148 to 872 µg kg^-1 and only the turkey breast pate showed a concentration lower than the LOQ. The descending order of p-cresol level in smoked samples was: sausage > shredded tuna > salami > turkey breast > hamburger > turkey breast pate. In three analyzed samples, the results showed that the p-cresol migrates from the surface to the food inner. Finally, the proposed method was simple and efficient to quantify high levels of this contaminant in smoked foods and it could be a useful tool for the monitoring food safety and quality.

Application of gas sensors for modelling the dynamic growth of Pseudomonas in pork stored at different temperatures

Pseudomonas have a faster growth rate over other bacteria in chilled meat under aerobic conditions. A non-destructive method for modelling the dynamic growth of Pseudomonas in pork stored at different temperatures using gas sensors was presented in our work. Based on selected gas sensor data, the first-order kinetic equations (Gompertz and Logistic Functions) combined with the secondary model (Square-root Function) effectively simulated Pseudomonas growth in pork at different temperatures with R² and RMSE values of 0.71-0.97 and 0.27-0.84, respectively. Additionally, these models showed high accuracy with correlation coefficients greater than 0.90, in addition to several individual accuracy values. Furthermore, HS-SPME/GC-MS results demonstrated the presence of identified key volatiles in samples inoculated with Pseudomonas, including three amine compounds (mercaptamine, 1-octanamine and 1-heptadecanamine), phenol and indole. Our work showed that gas sensors are a rapid, easy and non-destructive method with acceptable feasibility in modelling the dynamic growth of spoilage microorganisms in meat.