RESUMO
This study investigates the potential of novel heme-ligand complexes, derived from heme-iron isolated from porcine hemoglobin by enzymatic hydrolysis, to use as pigments for meat products. Five alternatives to sodium nitrite were identified as possible heme ligands and stabilizing agents of the red conformation of heme. The effects of 4-methylimidazole, methyl nicotinate, pyrrolidine, piperidine, pyrazine and sodium nitrite (as comparative benchmark) on the color of heme-iron extract and pure hemin standard were studied in solution. The ligand affinity and heme-ligand stability was assessed over time in solution by UV-Vis absorbance spectroscopy and CIELAB color space parameters. The CIE redness score a* was used as a single measurement to propose a predictive model based on the following parameters: heme source (heme-iron extract or hemin standard), heme-to-ligand molar ratio (1:20 to 1:300), and storage time (up to 32 days). The optimal concentration at which each ligand can be added to either heme source, as well as the stability of the red color of the formed heme-ligand complexes in-solution was determined. Heme-iron extract-derived samples showed increased redness and color stability as compared to their hemin counterparts. No ligand showed as much affinity for heme as sodium nitrite. As the most promising ligand candidates, methyl nicotinate and 4-methylimidazole started to show color changes at a 1:50 molar ratio, but higher amounts (1:100 and 1:300, respectively) were required to attain the maximum redness possible with the highest stability.
RESUMO
The most important lesion to be overlooked when performing visual-only inspection of the lungs is embolic pneumonia. The aim of the present study was to assess the additional human health risk represented by overlooking cases of pyaemia represented by embolic pneumonia in finisher pigs, when conducting visual-only compared to palpation of the lungs, as is the traditional meat inspection procedure. An examination of bacteria isolated from 19 finisher pigs identified with embolic pneumonia at traditional meat inspection was undertaken. From each pig samples were taken from various organs (lungs, spleen, heart, liver and kidney), from the carpal joints (A. carpi) and flexor muscle (M. flexor digitorum superficialis) on the right foreleg. These data were included in a risk assessment following OIE guidelines. Bacteria were isolated from 78 out of 127 tissue and swap samples taken (61% positive samples). Staphylococcus aureus (N=37) was the most frequently isolated bacterium. The predominant site of S. aureus was the lung. S. aureus was detected although less frequently in low numbers in some organs (<100CFU/sample) and muscle samples (<10CFU/sample). Only one MRSA isolate was found. Staphylococcus warneri (N=24) was the second most commonly found bacterium. There was no predominant site and the number of S. warneri was less than 50CFU per sample. The risk of a food-borne intoxication from S. aureus in relation to pyaemia in pigs was considered very low due to the low quantitative numbers of S. aureus in muscle tissue samples. Implementing visual-only inspection will reduce the exposure of S. aureus due to less cross-contamination and handling of the plucks by the meat inspectors. The human health risk associated with S. warneri was considered very low, due to the limited zoonotic potential of this bacterium. In conclusion, the additional human health risk in relation to possibly overlooking pyaemia in Danish finisher pigs was considered negligible when conducting visual-only compared to traditional meat inspection.
