Microbial composition and diversity of high-demand street-vended foods in Ecuador

Authors: CARDENAS, BYRON - ESCUELA SUPERIOR POLITECNICA DEL LITORAL; LLORENTE, ENRIQUE - ESCUELA SUPERIOR POLITECNICA DEL LITORAL; Gu, Ganyu; Nou, Xiangwu; ORTIZ, JOHANA - UNIVERSITY OF CUENCA (UC); MALDONADO, PEDRO - NATIONAL POLYTECHNIC SCHOOL OF ECUADOR; CEVALLO-CEVALLOS, JUAN - ESCUELA SUPERIOR POLITECNICA DEL LITORAL

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2024
Publication Date: 2/17/2024
Citation: Cardenas, B., Llorente, E., Gu, G., Nou, X., Ortiz, J., Maldonado, P., Cevallo-Cevallos, J. 2024. Microbial composition and diversity of high-demand street-vended foods in Ecuador. Journal of Food Protection. https://doi.org/10.1016/j.jfp.2024.100247.
DOI: https://doi.org/10.1016/j.jfp.2024.100247

Interpretive Summary: Street-vended foods are in high demand in many countries as a means of providing fast, inexpensive, and convenient access to food, and as an important income source for many families. However, the microbial safety and quality of street-vended foods is still poorly documented. In a collaborative study with Ecuador food scientists, the baseline microbiomes of the 10 most popular street foods consumed in three biggest cities in Ecuador was analyzed based on 16S rRNA gene high-throughput sequencing. Results derived from this study expand the knowledge on the bacterial profiling in popular foods and food sources, which can benefit the development of preventive strategies to reduce the spoilage and pathogenic bacteria in street-vended foods. The information can be utilized in many ways in food-related pursuits and to develop food safety and security programs in developing countries.

Technical Abstract: Developing countries such as Ecuador carry a heavy food safety burden but reports on the microbiological quality of their foods are scarce. In this investigation, the microbial diversity in 10 high-risk and mass-consumption street-vended foods including bolón, encebollado, food dressings, ceviche, chopped fruits, fruit juices, fruit salads, cheese, raw chicken, and ground beef in Quito, Guayaquil, and Cuenca, 3 major population centers in Ecuador, were evaluated using 16S rRNA gene High Throughput Sequencing. In total, 1,840 amplicon sequence variants (ASVs) were classified into 23 phyla, 253 families, 645 genera, and 829 species. In the tested food samples, Proteobacteria and Firmicutes were the most abundant phyla accounting for 97.41% of relative abundance (RA). At genus level there were 10 dominant genera identified: Acinetobacter (12.61% RA), Lactococcus (12.08% RA), Vibrio (8.23% RA), Weissella (7.43% RA), Aeromonas (6.18% RA), Photobacterium (6.32% RA), Pseudomonas (3.92% RA), Leuconostoc (3.51% RA), Klebsiella (3.49% RA) and Cupriavidus (2.86% RA). The highest microbial diversity indices were found in raw chicken, encebollados, fruit salads, and fruit juices from Guayaquil and Cuenca. From the sampled foods, 29 species were classified as food spoilage bacteria (FSB) and 24 as opportunistic pathogenic bacteria (OPB). Two groups associated with human diseases were identified, including bacteria belonging to the human gut microbiota (11 species), and human pathogenic bacteria (HPB, 26 species). The occurrence of recognized and opportunistic pathogenic bacteria, as well as human gut microorganisms, in the street vended foods indicated extensive risks for the consumers’ health. This study demonstrated the application of culture independent amplicon sequencing providing a more comprehensive view of microbial safety for street-vended food, which could be a useful tool to facilitate the control of foodborne diseases.