Baird parker agar

All samples collected during the experiments were tested for the presence of applied microorganisms, and analyses were carried out under a laminar flow hood using standard microbiological methods. To evaluate the presence and viability of the different microorganisms in the samples (viable and culturable), 100 µL of suspension from each sample was inoculated onto selective media for each microorganism: XLT-4 Agar (Xylose Lactose Tergitol 4, Scharlau, Barcelona, Spain) for S. Typhimurium detection; Baird Parker Agar (Scharlau, Barcelona, Spain) for S. aureus detection; Cetrimide Agar (Scharlau, Barcelona, Spain) for E. aerogenes detection; and Sabouraud Chloramphenicol Agar (Scharlau, Barcelona, Spain) for A. brasiliensis detection. Culture plates were incubated for 24–48 hours at 37 °C. After incubation, suspected bacteria colonies were streaked into a nutrient medium (Scharlab, S.L., Barcelona, Spain) and incubated at 37 °C for 24 hours. Then, API-test (Biomerieux, S.L., Barcelona, Spain) was performed to confirm the bacteria obtained. Filamentous fungi were identified on the basis of macroscopic and microscopic morphologic features (Figure 2).

The Minimum Bactericidal Concentration MBC is expressed as the lowest concentration of an antimicrobial agent which reduces the number of bacteria by 99.9% after an incubation time of 24 h (EUCAST 2000 ). MBC was determined after plating the contents of the wells and where no bacterial growth is visible on Petri dishes under sterile conditions. The plating was conducted at 37 °C under aerobic condition in MRS agar (Scharlab S.L., Spain) for L. rhamnosus GG and MHB agar (HiMedia Laboratories Pvt.Ltd., India) for S. epidermidis 444 at 48 h and 24 h respectively. For the co-culture, well-selected media are used to conduct the MBC; MRS agar was used to identify L. rhamnosus GG and the Baird Parker agar (Scharlab S.L., Spain) with egg yolk (Scharlab S.L., Spain) was used for the identification of S. epidermidis 444.