Indicator microorganisms for quality in pulque from three producing municipalities in the state of Mexico

Resumen

Objective: To evaluate the physicochemical parameters and microbiological quality of pulque produced in three municipalities in the State of Mexico: Temoaya, Jiquipilco, and Ocoyoacac.

Design/methodology/approach: The physicochemical parameters evaluated included pH, total soluble solids (°BX) and alcohol content.

In addition, microorganism’s indicative of microbiological quality was quantified, including: aerobic mesophilic bacteria, fungi, yeasts, and coliforms, complemented by the presence of lactic acid bacteria. Presumptive identification and antimicrobial susceptibility testing were performed on coliform isolates.

Results: The physicochemical results were within the typical ranges for pulque, with pH values 3.30 to 4.02, total soluble solids 4.62 to 6.37 °Bx and alcohol content 4.42 to 4.87%. Microbiological analyses revealed the presence of aerobic mesophiles, lactic acid bacteria, and yeasts in all samples. Coliform bacteria were detected only 20% of the samples. Biochemical test allowed the presumptive identification of Escherichia coli and Shigella flexneri. Antimicrobial susceptibility revealed, resistance of these isolates to antibiotic such as ampicillin, carbenicillin, cephalothin, cefotaxime and nitrofurantoin.

Limitations/implications: The study was limited to specific localities, which may affect the generalizability on the results. Nevertheless, it highlights the need to strengthen hygienic practices and microbiological control.

Findings/conclusions: The microbiological variability observed among municipalities highlights the influence of production and commercialization conditions. The detection of antibiotic-resistant bacteria represents a potential risk to food safety.