2026-04-13T06:35:26Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/3843232026-01-18T08:59:59Zcom_2072_1033col_2072_452950

urn:hdl:2117/384323 Improvement of the pour plate method by separate sterilization of agar and other medium components and reduction of the agar concentration Terrones Fernández, Inés Casino Alcalde, Pablo López Sevilla, Asunción Peiró, Sara Ríos Azuara, Santiago Nardi Ricart, Anna García Montoya, E. Asensio Adalid, Daniel Marqués Villavecchia, Ana María Castilla López, Roberto Gámez Montero, Pedro Javier Piqué Baella, Neus Àrees temàtiques de la UPC::Enginyeria agroalimentària::Ciències de la terra i de la vida::Microbiologia Agar Food -- Microbiology Drugs Cosmetics Microbiology Pour plate method TSA SDA VRBG Recovery Selectivity Agar Separation of components Pour plate Agar Aliments -- Microbiologia Medicaments Cosmètics Microbiologia Although the pour plate method is widely employed in microbiological quality control, it has certain drawbacks, including having to melt the culture medium before seeding. In this study, the preparation of the culture medium was modified by using a lower concentration of agar (10 g/L), which was separated from the nutrients during sterilization. The new protocol was assessed in media frequently used in microbiological quality control of food, cosmetics, and pharmaceutical products, with tryptic soy agar (TSA), Sabouraud 4% dextrose agar (SDA), and violet red bile glucose agar (VRBG). In comparison with the conventionally produced media, the modifications significantly improved the growth of Saccharomyces cerevisiae in SDA, Staphylococcus aureus, Salmonella enterica subsp. enterica serovar Typhimurium, and Candida albicans in TSA and Escherichia coli ATCC 8739 and ATCC 25922 and S. Typhimurium in VRBG. The modified VRBG was also more selective for Pseudomonas aeruginosa. Regarding physicochemical properties, a significantly lower pH was observed in TSA and VRBG and lower strength values in TSA. Sterilizing agar separately from the other components of the medium and reducing the agar concentration to 10 g/L can improve microorganism growth and enhance the selectivity of differential media in the pour plate method. These modifications could facilitate the automation of this culture technique Postprint (published version) 2023-01-10 Article https://journals.asm.org/doi/full/10.1128/spectrum.03161-22 http://creativecommons.org/licenses/by/4.0/ Open Access Attribution 4.0 International