## 2 Materials and Methods  
Manufacturing of culture media  
All media (TSA, TSB, SDA, Sabouraud dextrose broth, and VRBG) were manufactured at Reactivos para Diagnostic (RPD), S.L. (Sentmenat, Barcelona, Spain) from dehydrated ingredients, which were mixed in 250 mL of deionized water and resuspended, and sterilized using the following: (1) moist heat (121 \({}^{\circ}\)C for 15 min) in an autoclave (AES-150 model, Raypa, Barcelona, Spain) or by boiling (VRBG); (2) a water bath in a microwave, in a glass bottle with a special rubber cap, specially designed for this purpose (Figure 1). The cap was punctured with a 28 mm sterile needle, and capped with a sticker to allow gas elimination and to prevent contamination. For the microwave method, the bottle with thehydrated medium was placed in a polycarbonate tube (14 cm high and 8 cm in diameter) filled with water (Figure 1), covering the whole part of the filled bottle, similar to a water bath. This tube allowed a homogeneous temperature distribution and a safety barrier to be created. The cycles were programmed, with different durations (from 3 to 20 min), at 1000 W, in a conventional microwave oven (Cecotec ProClean 5110 Inox, Valencia, Espana). The only difference in the resulting culture media was the sterilization method. The reference media were sterilized using common autoclaving conditions, as specified by the manufacturer. The TSA and SDA were autoclaved at 121 \({}^{\circ}\)C for 15 min, and the VRBG was boiled for 1 min until completely dissolved. Using the microwave method, all culture media were sterilized in a microwave oven, as mentioned above. Solid culture media were maintained in bottles at room temperature, until being dispensed onto Petri plates (with the bacterial inoculum, using the pour plate method or without it using spiral inoculation). All culture media were pH adjusted, if necessary (to pH values of 5.6 \(\pm\) 0.2 for SDA; 7.3 \(\pm\) 0.2 for TSA, and 7.4 \(\pm\) 0.2 for VRBG), to achieve the physicochemical properties required for each medium. Micro-organism strains used  
The microbial strains used in the productivity and selectivity assays were obtained from a reference strain collection (American Type Culture Collection, ATCC). The reference strains were sub-cultured once to obtain stock strains, from which the stock and working cultures were prepared. The strains used (Table 1) were those recommended in ISO 11133:2014/amended 1:2018 for the quality control of TSA, TSB, SDA, Sabouraud dextrose broth, and VRBG [19]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Culture Media** & **Assay** & **Micro-Organism** & **ATCC 1** & **WDCM 2** \\ \hline \multirow{7}{*}{ TSA} & & _Escherichia coli_ & 8739 & 00012 \\  & & _Candida albicans_ & 10231 & 00054 \\  & & _Pseudomonas aeruginosa_ & 9027 & 00026 \\  & & _Staphylococcus aureus_ & 6538 & 00032 \\  & & _Apergillus brasiliensis_ & 16404 & 00053 \\  & & _Bacillus subtilis_ & 6633 & 00003 \\  & & _Listaria monocytogenes_ & 13932 & 00021 \\  & & _Salmonella enterica_ subsp. & & \\  & & _ enterica_ ser. & 14028 & 00031 \\  & & _Typhimuriumium_ & & \\  & & _Clostridium perfingens_ & 13124 & 00007 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Micro-organisms and culture media tested. Figure 1: Design of the cap on the bottle for sterilization of culture media in a microwave oven equipped with a water bath. Inocula preparation  
The stock culture strains were maintained in either TSA (bacteria) or SDA (molds and yeasts) slant tubes (RPD S.L.) under refrigeration. The inocula of the studied culture were prepared according to ISO 11133 [19]. Each strain was verified before use in non-selective media (TSA for bacteria, and SDA for molds and yeasts) and then cultured in appropriately selected and differential media, according to ISO 17025:2017 (ISO 17025) [20]. Stock dilutions were prepared in maximum recovery diluent (RPD S.L.)