ABSTRACT
Investigation of microorganism associated with the spoilage of banana and Avocado Pear were carried out. The isolation of bacteria from the banana and Avocado Pear was carried out on Nutrient agar, MacConkey agar and salmonella shigella agar while that of fungi was on Sabouraud Dextrose agar. A total of seven (7) bacteria and two (2) fungi isolates were obtained. The bacteria isolates were Escherichia coli, Staphylococcus aureus, Pseudomonas spp, Klebsiella spp, Enterococcus spp, Salmonalla spp and Shigella spp. The fungal isolates were Aspergillus flavus and Aspergillus niger The highest occurring bacterium was Escherichia coli (40%),and the least were Salmonella and Shigella spp (10%) Staphylococcus aureus (30%), Pseudomonas spp (25%), Klebsiella spp, (25%), Enterococcus spp (20%). The highest fungus was Aspergillus flavus (25%), and the least was Aspergillus niger (15%). The result showed that Avocado Pear and banana from Ndioru market has the highest bacteria count of 6.6 x102cfu/ml, 5.3 x 104cfu/ml and fungal count of 2.9 x 104cfu/ml. The comparison showed that all the bacterial and fungal isolates associated with the spoilage are present in the Avocado Pear except Shigella spp and Aspergillus niger which were absent in the banana. It also showed that the bacteria isolate were most predominant compared to the fungal isolates. The presence of these bacteria and fungi present a health risk factor to people who consume fruits without washing. Consumers should avoid consumption of spoilt fruits to avoid health implications that may lead to death.
CHAPTER ONE
INTRODUCTION
1.1 INTRODUCTION
Food spoilage refers to the various changes in which the food becomes less palatable or even toxic to consumers. These changes may be accompanied by alterations in taste, smell, appearance or texture .Numerous microbial defects of agricultural crops are characterized by the type of microorganism responsible for their deterioration (Akinmusire, 2011).
A fruit is the edible part of a mature ovary of a flowering plant. It is usually eater raw. When matured, they may be either fleshy or dry. Fleshy fruits are further classified into berry (orange, tomatoes, pineapple, Avocado Pear, and banana), drupes (plume, coconut, almond, cherry) and plumes such as apple and pear. The dry fruits, unlike the fleshy fruits which have unlayered pericarpe are classified in to dehiscent (pod, follicle and capsule) and indehiscent fruits like achene, samara, cashew etc (Jay, 2000).
Fruits and vegetables are vital sources of nutrient to human beings. They give the body the necessary vitamins, fats, minerals and oil in the right proportion for human growth and development. Fruits and vegetables are however, have serious changes to their existence. These incline changes in climatic conditions, pest and microbial attack. Over the years, there has been the need to isolate the microorganisms associated with the spoilage as a way of finding a means of controlling it (Akinyele and Akinkunmi, 2012).
Susceptibility of fruits and vegetables is largely due to differential chemical composition such as Ph and moisture contents are associated with greater predisposition to microbial spoilage. The occurrence of fungal spoilage of fruits is also recognized as a source of potential health hazard to man and animals. This is due to their production of my mycotoxins (naturally occurring toxic chemicals often of aromatic structure) which are capable of producing aflatoxins in man following inhalation or ingestion.
Banana and Avocado Pear are botanically called Musa sapientum and Persea americana. Their spoilage is due to biotic factors and being that they are perishable fruits. Avocado Pear fruit can be fleshly eaten or cooked. It can be used in the preparation of jellies, juice and jams. It has a great application in the preparation of fruit salad and desert (Mitra, 1997). Banana contains about 75% water, 23% carbohydrate and 3% protein. Banana without the peel is a good source of vitamins, potassium and fiber. Banana fruit may be eaten raw or cooked. The fruit can also be processed for a number of products. Ripped fruit can be pulped for puree for a variety of products including ice cream, yoghurt, cake bread, m Green (unripe banana) can be fried and sliced as chips.
Banana leaves are not eaten but maybe used for wrapping food in cooling. The banana foliage and pseudo stem are used as cattle feed during dry period in some banana producing areas. Banana has a good source of energy but need to be supplemented with proteins.
These fruits are usually displayed on benches and in baskets for prospective customers in the open market until sold, thereby exposing them to further microbial infection beside those associated with these whole fruit surface and those from adjacent infected fruits (Baiyewu et al., 2007).
In developing countries, post harvest deterioration are often more severe due to inadequate storage and transportation facilities. Microbial fruit infection may occur during the growth season, harvesting, handling, transport and post harvest storage and marketing conditions, or after purchasing by the consumer. Fruits contain high levels sugar and nutrient elements and their low pH values makes them particularly desirable to fungi decay (Singh and Sharma, 2007). Studies by Li-cohen and Bruhiri (2002) shows that fungi can survive and grow on fresh produce and that the nutrient content (carbohydrate, protein and fat) of fresh produce support pathogens.
Fruits are affected by a wide array of microorganisms causing its decay. Spoilage microorganisms can be introduced to the crop on the seed itself, during crop growth in the field, during harvesting and post harvest handling or during harvest and distribution (loading and offloading) (Barth et al., 2009).
Those type of soil born spoilage microbes that occur on produce are the same spoilage microorganisms that are present oh harvesting equipments, on handling equipment in the packaging house, in the storage facility and on food contact surfaces throughout the distribution chain.
Therefore, early intervention measures during crop development and harvesting through the -use of Good Agricultural Practices (GAP) will provide dramatic reduction in the yield loss due to deterioration at all subsequent steps in the food (Barth et al., 2009).
1.2 AIM AND OBJECTIVES
• To determine the bacteria present in the spoilage of banana and Avocado Pear.
• To determine the fungi present in the spoilage of banana and Avocado Pear.
• To compare the microorganisms associated with the spoilage of banana and Avocado Pear.
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