Laboratory Based Experimental Study on Microbial Spoilage of Commercially Available Fruits

Abstract

Microorganisms are everywhere. They can be found in the air, in water, in soil, on animals and even on humans. Some are beneficial, such as those used to make fermented dairy and meat products. Others cause spoilage of various food products. Eating fruits is a healthy practice due to its nutritional composition but when it gets spoiled by microbes, it can be harmful for human consumption. Microorganisms have been reported to cause extensive deterioration of fruits. Some of these microorganisms cause rotting, discoloration or fermentation of the fruits which affect their preservation. The study was done to identify and analyse  microbial diversity that causes the spoilage. Pour plate method was used for the isolation of microbes from spoil fruit. A portion of the fruit was aseptically inoculated into the beaker; it was homogenized and then diluted. The colonies were identified by standard bacteriological procedures. Gram’s staining was performed to determine if the organism is gram negative or gram positive. Further confirmatory biochemical tests were done such as catalase, coagulase and oxidase. The identification of the isolated fungi was done both macroscopically and microscopically. This study and experiments revealed that the rotten or spoiled fruit possess appreciable number of microbes. The Microorganisms isolated and observed were bacteria and fungi majorly. This is due to various processes taking place in the rotten fruit which favoured bacterial and fungal growth. It could also be as a result of the moisture content of the fruit as well as the difference in the nutritional composition of the fruits. This work finds that there are microorganisms that could be responsible for inducing spoilage in the fresh fruit. Fruits are a good source of nutrient and could be used for many applications. However to reduce the susceptibility of the fruit to microbial spoilage and to ensure its effectiveness in different applications and safety measures should be taken. Hence if you want to prevent spoilage of food by micro-organisms, you must remove the conditions which are appropriate for their growth and preserve them with the best possible techniques.