Serotyping and genotyping of salmonella strains isolated from broilers, chicken carcasses before and after chilling, and frozen chicken breasts produced in the states of Mato Grosso do Sul and Santa Catarina, Brazil

The present study investigated the effectiveness of a single Salmonella prevention and control program applied in two different processing plants, located in the states of Mato Grosso do Sul (plant A) and Santa Catarina (Plant B), belonging to the same company, and identified Salmonella strain subtypes isolated from broilers, carcasses before and after chilling, and frozen chicken breasts. The Salmonella prevention and control program was 90% effective in plant A and 100% in plant B, considering a level of 10% positive samples per frozen chicken breast batch acceptable. A total of 128 strains were serotyped, being 10 from drag swabs, 31 from cloacal swabs, 83 from carcasses, and 4 from frozen chicken breasts. After serotyping analysis, 30 strains isolated at different processing steps and drag swabs, and three Salmonella Minnesota strains isolated in 2012 in plant A, were genotyped by PFGE. In plant A, the most frequently strain isolated was Salmonella Minnesota (90.35%), followed by Salmonella Newport (8.77%), and in Plant B, Salmonella Senftenberg (80%). Salmonella Minnesota strains were differentiated by PFGE into 19 pulsotypes distributed in three clusters. The phenotypic identification by serotyping of four strains diverged from their PFGE genotypic results. Most Salmonella Minnesota strains genotyped in plant A and the strains isolated from environmental samples in 2012 in the same broiler processing plant belong to a single cluster, confirming the dominance and persistence of this clone over time.

Serotyping and genotyping of salmonella strains isolated from broilers, chicken carcasses before and after chilling, and frozen chicken breasts produced in the states of Mato Grosso do Sul and Santa Catarina, Brazil

The present study investigated the effectiveness of a single Salmonella prevention and control program applied in two different processing plants, located in the states of Mato Grosso do Sul (plant A) and Santa Catarina (Plant B), belonging to the same company, and identified Salmonella strain subtypes isolated from broilers, carcasses before and after chilling, and frozen chicken breasts. The Salmonella prevention and control program was 90% effective in plant A and 100% in plant B, considering a level of 10% positive samples per frozen chicken breast batch acceptable. A total of 128 strains were serotyped, being 10 from drag swabs, 31 from cloacal swabs, 83 from carcasses, and 4 from frozen chicken breasts. After serotyping analysis, 30 strains isolated at different processing steps and drag swabs, and three Salmonella Minnesota strains isolated in 2012 in plant A, were genotyped by PFGE. In plant A, the most frequently strain isolated was Salmonella Minnesota (90.35%), followed by Salmonella Newport (8.77%), and in Plant B, Salmonella Senftenberg (80%). Salmonella Minnesota strains were differentiated by PFGE into 19 pulsotypes distributed in three clusters. The phenotypic identification by serotyping of four strains diverged from their PFGE genotypic results. Most Salmonella Minnesota strains genotyped in plant A and the strains isolated from environmental samples in 2012 in the same broiler processing plant belong to a single cluster, confirming the dominance and persistence of this clone over time.(AU)

Effect of aging on bioactive amines, microbial flora, physico-chemical characteristics, and tenderness of broiler breast meat.

The objective of this study was to investigate the influence of aging on the levels of bioactive amines, microbial flora, physico-chemical characteristics, and tenderness of broiler breast. Forty-five 1-d-old Cobb broilers were aged at temperatures from 1.0 to 5.7 degrees C for 8 h. Nonaged broiler breast contained spermine, spermidine, and low levels of putrescine. There was prevalence of aerobic mesophiles followed by Pseudomonas. Mean pH, nonprotein N, weight loss after roasting, and shear force were 5.92, 0.46 g of N/100 g, 19.4%, and 5.57 kg, respectively. During aging, there was a significant increase in Pseudomonas and on the levels of amines. Two different amines were detected - tyramine and histamine. Aging resulted in a significant increase in tenderness without affecting pH, non-protein N, and weight loss after roasting. There was significant correlation between aging temperature and total bioactive amine levels. Aging above 4.9 degrees C induced the formation of histamine; therefore, aging should be performed at temperatures < or = 4.9 degrees C to prevent the formation of this amine, which has been associated with human health hazards. During storage of aged broiler breast at -18 +/- 1 degrees C for 89 d, there was no significant difference on pH, nonprotein N, and weight loss after roasting; however, there was a significant decrease on spermine, spermidine, putrescine, and tyramine levels. On the 89th day of storage, histamine was detected, and the shear force was significantly lower when compared with the samples immediately after aging. Therefore, the storage time of aged breast should not exceed 64 d to prevent histamine formation and to avoid excessive softening of the meat. Histamine in aged broiler breast could be used as an index of aging temperatures above 4.9 degrees C and also of frozen storage for more than 64 d.