The Assessment of the Microbial and Hygienic Quality of Leafy Vegetables Along with Associated Microbials among Vegetables Purchased from Different Markets in Guyana


Published: 2023-08-03

DOI: 10.56557/ajmab/2023/v8i28331

Page: 37-51

Vashthi Sukdeo

Department of Biology, Faculty of Natural Sciences, University of Guyana, Guyana.

Ruth Daniel *

Department of Biology, Faculty of Natural Sciences, University of Guyana, Guyana.

Abdullah Ansari

Department of Biology, Faculty of Natural Sciences, University of Guyana, Guyana.

*Author to whom correspondence should be addressed.


Fruits and vegetables are important to human health because they provide nutritional benefits, they are a good source of vitamins and minerals and help to improve the immune system of individuals. It was advised by the Food and Agriculture Organization of Guyana that individuals should consume more fruits and vegetables to boost their immune systems during the Coronavirus pandemic. Due to the increase in consumption of fruits and vegetables, there can also be an increase in cases of food-borne diseases, as evident from studies done in countries such as, the United States, Malaysia, and India. The objectives of this research was to identify the presence of microorganisms on leafy vegetables, Lactuca sativa (lettuce), Brassica oleracea (cabbage), and Amaranthus viridis (callaloo), that were purchased from local markets and to determine if washing with tap water only, will significantly decrease the concentration of microorganisms on the vegetables by performing microbial assessments.

It was found that the most common microorganisms present on the leafy vegetables were pathogenic bacteria such as Neisseria spp., Pseudomonas aeruginosa, Paracoccus marcusii, Pseudomonas fluorescens, Bordetella pertussis, and Klebsiella pneumonia. The results of a Wilcoxon signed-rank test (p value = 1) revealed that washing with tap water alone did not significantly decrease the quantity of microorganisms present on the leafy vegetables (avg: 3.305x10-2 CFU/ml). Therefore, it is recommended that other hygienic methods such as washing with salt, lemon juice, or vinegar should be utilized in order to significantly reduce the concentration of the microorganisms present on the leafy vegetables.  

Keywords: Leafy vegetables, foodborne diseases, pathogenic microorganism, hygienic method

How to Cite

Sukdeo , V., Daniel , R., & Ansari , A. (2023). The Assessment of the Microbial and Hygienic Quality of Leafy Vegetables Along with Associated Microbials among Vegetables Purchased from Different Markets in Guyana. Asian Journal of Microbiology and Biotechnology, 8(2), 37–51.


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Slavin JL, Lloyd B. Health benefits of fruits and vegetables. National Library of Medicine; 2012. Available:

Seelall S. Celebrating the International Year of Fruits and Vegetables. United Nations Guyana; 2021. Available:

Al-Agroudi MA, Morsy ATA, Ismail MAM, Morsy TA. Protozoa causing food poisoning. National Library of Medicine; 2016. Available:

Addo MG, Agordzo S, Badu K. Efficacy of vinegar, salt solution and lemon juice as antimicrobial agents in reducing: The microbial load of lettuce sold at ayeduase, a suburb of kumasi, Ghana; 2020. Available:

CDC. Foods That Can Cause Food Poisoning. Center of Disease Control and Prevention; 2020. Available:

CDC. Lettuce, Other Leafy Greens, and Food Safety. Center of Disease Control and Prevention; 2021. Available:

Cerna-Cortes JF, Leon-Montes N, Cortes-Cueto AL, Salas-Rangel LP, Helguera-Repetto AC, Lopez-Hernandez D, et al. Microbiological Quality of Ready-to-Eat Vegetables Collected in Mexico City: Occurrence of Aerobic-Mesophilic Bacteria, Fecal Coliforms, and Potentially Pathogenic Nontuberculous Mycobacteria. Hindawi; 2014. Available:

de Silva GDD, Abayasekara CL, Dissanayake DRA. Freshly Eaten Leafy Vegetables: A Source of Food Borne Pathogens?; 2013. Available:

Marine SC, Pagadala S, Wang F, Pahl DM, Melendez MV, Kline WL, et al. The Growing Season, but Not the Farming System, Is a Food Safety Risk Determinant for Leafy Greens in the Mid-Atlantic Region of the United States. ASM Journals; 2015. Available:

Rosberg AK, Darlison J, Mogren L, Alsanius BW. Commercial wash of leafy vegetables do not significantly decrease bacterial load but leads to shifts in bacterial species composition. Science Direct; 2021. Available:

Jagessar RC, Ramchartar N, Spencer O. The antimicrobial activity of various solvent type extracts from selective fruits and edible plants. AgEcon Search; 2015. Available:

De Oliveiraa MA, de Souza VM, Bergamini AMM, De Martinis ECP. Microbiological quality of ready-to-eat minimally processed vegetables consumed in Brazil. Science Direct; 2011. Available:

Tripathi N, Sapra A. Gram Staining. National Library of Medicine; 2021. Available:

Maffei DF, Silveira MA, da Silva MBR, Moreira DA, Lourenço FR, Schaffner DW, et al. Consumption data and consumer handling practices of leafy greens in the City of São Paulo, Brazil: Useful Information for Quantitative Microbiological Consumer Phase Risk Assessments; 2020. Available:

Hanna SAS. NEISSERIA. Science Direct; 1999. Available:,Neisseria%20spp.,1.0%20%C3%97%202.0%E2%80%933.0%20%CE%BCm

Calder A, Menkiti CJ, Çağdas A, et al. Virulence genes and previously unexplored gene clusters in four commensal Neisseria spp. isolated from the human throat expand the neisserial gene repertoire. National Library of Medicine; 2020.


CDC. Pseudomonas aeruginosa in Healthcare Settings. Center of Disease Control and Prevention; 2019. Available:

Iglewski BH. Chapter 27 Pseudomonas. National Library of Medicine; 1996. Available:

Harker M, Hirschberg J, Oren A. Paracoccus marcusii sp. nov., an orange Gram-negative coccus. Microbiology Society; 1998. Available:

Liu X, Xiang L, Yin Y, Li, H, Ma D, Qu Y. Pneumonia caused by Pseudomonas fluorescens: A case report. BMC; 2021. Available:

Biaggini K, Barbey C, Borrel V, Feuilloley M, Déchelotte P, Connil N. The pathogenic potential of Pseudomonas fluorescens MFN1032 on enterocytes can be modulated by serotonin, substance P and epinephrine. Pub Med; 2015. Available:

Lotha G. Whooping cough. Encyclopaedia Britannica; 2021. Available:

Ashurst JV, Dawson A. Klebsiella Pneumonia. National Library of Medicine; 2022. Available:,and%20gastrointestinal%20(GI)%20tract

Guyana Food Safety Authority. Kaieteur News; 2022. Available: