Estudo da relação do valor de pH da carne de frango com a sua carga microbiana

Abstract

The quality of meat, particularly chicken, is determined not only by the visual characteristics, which are evaluated by the consumer, but also by microbiological and physicochemical parameters that are important from the producer's point of view.The present study focused on quality control of chicken meat associated with animal welfare, particularly with regard to the pH value and the microbiological quality of the chicken caught day and night when related to factors such as fasting time and expects in the ante-mortem period, live weight and time of the post-mortem and rigor-mortis period. In order to carry out a more in-depth study regarding the quality parameters, pH, microbiological quality and color measurements were carried out after 24 hours of slaughter on the breast and on the shore leg; and texture only for the chest. In addition to this study, the aforementioned parameters were also evaluated over the shelf-life of two collections (24, 72 and 144 hours).Through the analysis of the results it was observed that only the post-mortem time has influence on the pH of the chicken, breast and leg with coast, although it stabilizes until the 24 hours. In the color of the chest the direct connection with the pH was visualized, since the studied meat was characterized as PSE (5,7 ≥ pH ≤ 5,8; L *> 50). In microbiological quality it has been found that a more rigorous control of fasting times (thus avoiding cross-contamination) and handling by employees in the cutting area is required, since in general the number of microorganisms obtained has been high. In order to evaluate the texture of the breast, the shear strength test and the TPA were used, and it was verified that the breasts were harder, the elasticity and the adhesiveness had similar values and the secondary parameters (guminess and chewing) had significant differences in nocturnal picking.The study allowed to conclude the importance of controlling all the extrinsic factors so that the quality of the animal is not influenced. In the specific case of this project, it was verified that the quality problems such as greenish color in the chest and the number of microorganisms high does not come from extrinsic factors, but intrinsic, as the case of feeding, genetics and physiological state.

Date of Award	22 May 2018
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Paula Teixeira (Supervisor) & Sónia Marília Castro (Co-Supervisor)