Violet red bile glucose agar vrbg

Each raw beef patty sample was collected under aseptic conditions and mixed with buffered peptone water (Panreac, Darmstadt, Germany). To determine the TVC, Plate Count Agar (PCA; Panreac) was employed and incubated at 37 °C for 48 h. Enumeration of the LAB was performed using De Man, Rogosa, and Sharpe agar (MRS; Merck, Darmstadt, Germany), with an incubation period of 48 h at 37 °C. For Enterobacteriaceae enumeration, Violet Red Bile Glucose Agar (VRBG; Panreac) with a double layer was used and incubated at 37 °C for 24 h. Microbiological analyses were conducted in duplicate, and microbial counts were expressed as logarithms of colony-forming units per gram (log CFU/g). Additionally, the presence of Salmonella sp. was assessed in 25 g of the beef patties. For this purpose, a 25 g sample was mixed with 225 mL of sterile buffered peptone water solution (0.1%, Panreac) for bacterial prepropagation. Selective proliferation of bacteria was carried out using Rappaport-Vassiliadis Soy Broth medium (Merck) and bacterial isolation was performed using Hektoen (Merck KGaA, Darmstadt, Germany) and Xylose Lysine Deoxycholate (XLD; Merck) agars. Previously, the microbiological characterization of CF was conducted, and the results are as follows: TVC: 6.83 log CFU/g; Enterobacteriaceae: <1.6 log CFU/g; LAB: 2.71 log CFU; Salmonella sp.: absence; and Listeria monocytogenes: absence.