The study investigated microbial contamination of four samples of Solanummacrocarpon leaves commonly known Garden egg leaves (unwashed, washed and washed with different salt concentration). The objective was to isolate and identify microorganisms present on the vegetable before washing (unwashed), after washing with sterile water and also in brine (the leaves wholly immersed in water and different salt concentration for 15 seconds), the possible causes of contamination, as well as to investigate the presence of pathogen that may constitute a public health hazard from the consumption of the vegetable. The vegetable samples were obtained from Eke.Awka Market from four different vendors under aseptic conditions (in sterile plastic bags to eliminate cross contamination) and transported to the laboratory of Applied Microbiology and Brewing, NnamdiAzikiwe University, Awka within 30.40 mins of collection. Nutrient agar and Sabouraud dextrose agar were used in the study as culture media, while pour plate techniques involving laying of sample in the poured media was employed.The samples were qualitatively analyzed by microbiologically analysis which involved identification of the isolates using different biochemical analysis with the following results for bacteriological analysis: Bacillus sp, Escherichia spand Staphylococcus sp.for unwashed, Staphylococcus sp and Enterobacterspfor washed and washed vegetables with different salt concentration (2.5%, 5% and 7.5% NaCl) showed the presence of Pseudomonas sp, Bacillus sp, Micrococcus spand Enterococcus sp.The mold detected were Mucorsp, Penicillumsp,Rhizopussp,Aspergillussp and Fusariumsp.Yeast were also detected. Fusariumsp were detected in washed samples with salt concentration of 5% and 7.5% because they are halotolerant but the growth can be much more inhibited at a higher salt concentration, while mucorsp,Penicillumspand were detected in unwashed samples and yeast were detected in washed samples.



                                                              CHAPTER ONE


1.1: Background of Study

Food hygiene has been defined as meaning all the measures necessary for ensuring the safety, wholesomeness and soundness of the food at all stages from farm to table. The object of food hygiene practice consists of the production and serving of food as free as possible from contamination.

Vegetables provide the body with vitamins and minerals in addition to the basic carbohydrates and proteins. Vitamins and minerals are not stored for long in the human body and, hence, there is need for daily consumption.

In the past decade, outbreaks of human illness associated with the consumption of raw vegetables and fruits have increased. Changes in agronomic, harvesting, distribution, processing and consumption patterns and practices have undoubtedly contributed to this increase.  Pathogens such as Listeria monocytogenes, Clostridium botulinum and Bacillus cereus are naturally present in some soils and their presence on fresh produce is not rare. Salmonella, Escherichia coli, Campylobacter jejuni, Vibrio cholerae, parasites and viruses are more likely to contaminate fresh produce through vehicles such as raw or improperly composted manure, irrigation water containing untreated sewage or contaminated wash water.

Contact with mammals, reptiles, fowl, insects, and unpasteurized products of animal origin offers another avenue through which pathogens can access produce. Surfaces, including human hands, which come in contact with whole or cut produce represent potential points of contamination throughout the total system of growing, harvesting, packing, processing, shipping and preparing produce for consumption. Treatment of produce with chlorinated water reduces populations of pathogenic and other microorganisms on fresh produce but cannot eliminate them. Reduction of risk for human illness associated with raw produce can be better achieved through controlling points of potential contamination in the field, during harvesting, processing, distribution, in markets or at home (Beuchat and Ryu  1997).

Vegetables serve as a major part of our food supply. Raw vegetables harbor a number of pathogenic microorganisms, which may be dispersed over the plants or appear as microcolonies embedded in the plant tissues. Themicrobiological contaminants may have an adverse health effect. Fresh vegetables normally carry natural non.pathogenic epiphytic microorganisms, however, during growth, harvest, transportation, and further handling the produce can be contaminated with pathogens from animal and human sources. As most of these produce are eating without further processing, their microbial content mayrepresent a risk factor for the consumer’s health. The recent recognition of fresh fruits and vegetables as major vehicles of foodborneillness has led to increased research on mechanisms by which enteric pathogens contaminate and persist on and in this non.host environment. Interactions between foodborne pathogens and plants as well among the naturally occurring microbialcommunities contribute to endophytic and epiphytic colonization.

Consumption of fruit and vegetable products is commonly viewed as a potential risk factor for infection with enteropathogens such as Salmonella and Escherichiacoli O157, with recent outbreaks linked to lettuce, spinach and tomatoes. Routes of contamination are varied and include application of organic wastes to agricultural land as fertilizer, contamination of waters used for irrigation with faecal material, direct contamination by livestock, wild animals and birds and postharvest issues such as worker hygiene.

1.2 Aim of Study

To investigate the microbiological quality of freshly consumed vegetable (solanummacrocarpon leaves) sold in Eke.Awka Market.


1.3 Specific Objectives of Study

  1. Isolate microorganisms present in freshly consumed vegetable (Solanummacrocarpon) leaves sold in Eke.Awka Market.
  2. Identify the most common microorganisms present in Solanummacrocarpon leaves washed, unwashed and washed with varying concentration of NaCl.
  3. Investigate the presence of pathogens that may constitute a public health hazard from consumption of fresh Solanummacrocarpon vegetables