MICROBIOLOGY PATHOGEN RESEARCH PROJECT

THIS RESEARCH PROJECT IMPLEMENTS A STANDARDIZED SCIENTIFIC PROTOCOL TO DETECT AND QUANTIFY ESCHERICHIA COLI CONTAMINATION IN FRESH VANAME SHRIMP (LITOPENAEUS VANNAMEI). THE STUDY UTILIZES A DESCRIPTIVE QUALITATIVE DESIGN THAT INTEGRATES THE QUANTITATIVE MOST PROBABLE NUMBER (MPN) METHOD WITH QUALITATIVE LABORATORY CONFIRMATION. TESTING PROCEDURES ARE STRICTLY ALIGNED WITH ISO 16649-3:2015 AND ISO 7218:2007, BEGINNING WITH A PRESUMPTIVE PHASE USING MINERAL MODIFIED GLUTAMATE MEDIUM (MMGM) TO DETECT LACTOSE FERMENTATION AND GAS PRODUCTION.

TO ENSURE ACCURACY, PRESUMPTIVE RESULTS ARE FOLLOWED BY A CONFIRMATORY PHASE ON TRYPTONE BILE X-GLUCURONIDE (TBX) AGAR, WHICH SPECIFICALLY IDENTIFIES THE PRESENCE OF THE β-GLUCURONIDASE ENZYME. THIS RIGOROUS METHODOLOGY ALLOWS FOR A CLEAR SCIENTIFIC DISTINCTION BETWEEN GENERAL COLIFORM PRESENCE—SUCH AS ENTEROBACTER SPP. OR CITROBACTER SPP.—AND SPECIFIC E. COLI PATHOGENS, ENSURING THAT INITIAL SCREENINGS DO NOT LEAD TO FALSE-POSITIVE CONCLUSIONS.