ABSTRACT
The purpose of the present study was to investigate the physicochemical characteristics, meat quality, oxidative stability and sensory properties of lamb meat during 0, 7 and 14 day of the dry aging process. The M. longissimus lumborum (LL) and M. longissimus thoracis (LT) muscles from male Akkaraman lambs were used. The pH values of the LT and LL cuts were not changed during the aging periods. The LT cuts had significantly higher weight loss, a* and b* values, and lower shear force compared to the LL cuts. However, dry aging led to greater decreases in shear force in the LL cuts on 7th day of aging. The total mesophilic aerobic counts, total psychrophilic counts, Enterobacteriaceae counts, lactic acid bacteria, and yeast-mold counts were increased during the aging process. The sensory panel scoring showed a significant difference in the LL cuts and no significant difference in the LT cuts compared to the control group. There were significant changes in sensory panel scores for the LL cuts, whereas there were no significant changes for the LT cuts according to the non-aged samples. In conclusion, dry aging improved the quality of both cuts, however, the LL muscle of lamb was more suitable for dry aging. Moreover, 7 days were sufficient to produce the desired sensory properties in the lamb loins. Increasing the aging time from 7 to 14 days did not appreciably affect the sensory attributes or tenderness.
ABSTRACT
Campylobacter jejuni, a Gram-negative rod, is a zoonotic pathogen associated with human acute bacterial gastroenteritis worldwide. The flagellum, composed of more than 35 proteins, is responsible for colonization of C. jejuni in the host gastrointestinal tract as well as inducing protective antibodies against the homologous serotype. In our previous study, we demonstrated that the flagellar capping protein (FliD) is an immunodominant protein that reacted strongly to sera from field chickens. In this communication, we mapped linear immunoreactive epitopes on FliD using a set of 158 synthetic peptides of 15-mer overlapping with 11 amino acid residues on peptide microarrays with sera from field chickens. The results from peptide microarrays showed (1) no cross-reactivity of the immobilized peptides with the secondary anti-chicken antibody in the control incubation, and (2) heterogeneous patterns of sera reacting to the immobilized peptides. The peptides that reacted to more than three chicken sera and had higher averages of fluorescence units were selected for further validation by the peptide ELISA. The results showed peptides 24, 91 and 92 had relatively high reactivity and less variation among 64 individual serum samples, indicating these peptides represented the shared immunodominant epitopes on the C. jejuni FliD protein. These peptides were also recognized by sera from chickens immunized with the purified recombinant FliD protein. The findings of the specific shared linear immunodominant epitopes on FliD in this study provide a rationale for further evaluation to determine their utility as epitope vaccines covering multiple serotypes for chicken immunization, and subsequently, for providing safer poultry products for human consumption.
