## 4 Discussion
### Effect of Addition of CFS from LAB on Beef Quality
The beef samples treated with the addition of CFS exhibited an average increase in microbiological growth of 0.2643 0.26 log CFU/g per day, whereas the control beef samples demonstrated an average increase in microbial growth of 0.3962 0.39 log CFU/g per day. The R2 value of the regression equation pertaining to the beef soaking therapy in chronic fatigue syndrome (CFS) is 0.9704, suggesting that about 97.04% of the variability in the regression model can be accounted for by the included components and their interactions. Based on the findings of the _E. coli_ growth regression analysis, it was observed that the slope value for the control beef (\(-\)0.0604) was comparatively greater than that of the beef subjected to CFS treatment (\(-\)0.182). This study illustrates the efficacy of CFS in inhibiting microbial proliferation in beef. The beef samples that were treated with the addition of CFS had an average decrease in _E. coli_ growth of 0.1182 \(\pm\) 0.12 log CFU/g per day. In contrast, the control beef samples displayed an average decrease in _E. coli_ growth of 0.0604 \(\pm\) 0.06 log CFU/g per day. The R2 value of the regression equation for the beef soaking therapy in CFS is 0.8466, suggesting that about 84.66% of the variation in the regression model can be accounted for by the interaction of the factors. The beef used for this study was 9 h post-slaughter at the time of its cutting. Following the process of slaughter, beef undergoes a slow decline in pH levels from an initial value of 7.0 to a range of 5.6-5.7, ultimately stabilizing at a final pH of approximately 5.3-5.7. The decrease in quantity was instigated by the glycolysis process of the meat. This observation indicates that the beef utilized exhibits indications of undergoing the glycolysis process. The biochemical pathway by which glycogen in the muscles of beef is converted into lactic acid by the action of glycogen enzymes, in the absence of oxygen, is referred to as glycolysis. The pH of the beef increased until the ninth day in both treatment groups. According to previous research by [PERSON] et al. [22], beef exhibits increased microbial growth within the pH range of 6.2 to 7.2. However, it demonstrates enhanced resistance against microbial damage when the pH level falls within the range of 5.1 to 6.1. The olfactory, visual, and tactile properties of beef undergo alterations when reaching a pH of 6.8, which signifies the initiation of protein degradation. The bacteria responsible for the process of decay have the ability to enzymatically degrade proteins, resulting in the production of several malodorous compounds including cadaverine, indole, skatole, mercaptans, amines, and hydrogen sulfide (H\({}_{2}\)S). The degradation process will result in an elevation in pH due to the weak acidic nature of mercaptans and H\({}_{2}\)S, the basic properties of indole and skatole, the strong basicity of amines and cadaverine, and the weak basicity of indole and skatole. Based on the observed pH values, it can be determined that microbial growth exhibited an increase on the fourth day for the control beef, subsequently leading to spoilage commencing on the sixth day. The pH of beef exhibits variability; however, it can be effectively controlled with the application of CFS therapy. The results indicate that microbial growth did not commence until the seventh day, suggesting that the beef with CFS had not undergone spoilage. Color variations occur throughout the duration of the observation, up to its completion. Once the bacterial count reaches a range of 10\({}^{8}\)-10\({}^{9}\) CFU/mL (equivalent to 8-9 log CFU/g), a noticeable change in color will occur, transitioning from a dark red shade to a greenish hue. Metmyoglobin is formed as a consequence of the oxidation of myoglobin by hydrogen sulfide (H\({}_{2}\)S). The color of the control beef transitioned from a vivid red hue to a deeper shade of red between the sixth and ninth day.