Contamination with Escherichia coli in jumbo iced tea sold on Ayahanda Street, Medan: A Most Probable Number (MPN) approach

Abstract

Background: Diarrheal diseases are primarily transmitted through contaminated food and water, including ready to consume beverages like jumbo iced tea commonly sold by street vendors in urban areas. These beverages are highly susceptible to environmental contamination due to open air preparation and serving. This study aims to identify and quantify coliform bacteria in jumbo iced tea sold on Ayahanda Street, Medan.

Method: A descriptive quantitative cross-sectional design was employed, analyzing five samples selected via purposive sampling in February 2026. The microbiological contamination was evaluated using the Most Probable Number (MPN) approach, which consisted of presumptive, confirmed, and completed tests.

Results: The results revealed that all samples tested positive for coliform bacteria, presenting MPN values ranging from 240 to greater than 1100 MPN/100 mL. These findings completely violate the microbiological quality standards for safe drinking water, which strictly require 0 MPN/100 mL. Furthermore, isolation on Eosin Methylene Blue (EMB) agar exhibited metallic green colonies, confirming the specific presence of Escherichia coli in all tested beverages.

Conclusion: In conclusion, jumbo iced tea sold in this specific region is heavily contaminated with fecal coliforms, rendering it entirely unfit for human consumption. These findings highlight the critical necessity for strict implementation of food sanitation and hygiene practices during food processing and serving to mitigate severe public health risks.