Onion Is Associated With Micro-Organisms Which Are Capable Of Causing Spoilage
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Onion Is Associated With Micro-Organisms Which Are Capable Of Causing Spoilage
ABSTRACT
Onion is related with microorganisms that can cause spoiling. Rotten onions were examined under a microscope. A solution was prepared, and 10ml of onion sample was serially diluted from 1:10-1 to 1:1-5.
From the dilution, 1ml of each diluent was plated on nutrition, saboor, and dextrose agar to allow the growth of common bacterial and fungus from roffen onions.
Each dilution was performed on duplicate plates. The plates were gently sivirled to ensure uniform distribution of diluent and incubated for 24 hours in an inverted position at 370 degrees Celsius.
After 24 hours, the colorues were counted, with vales yielding 30 to 300 (to avoid TFTR and TNTC), and the viable count per ml was calculated by multiplying the average number of colories from the duplicate plates by the relevant factor (MPN table).
Gramme staining was performed on the colories, which were then studied under a microscope. Representative colories were separately cultured on nutrient agar slopes for confirmatory characterisation of the organism present.
A biochemical test for identification was also conducted. The results revealed a mixed flora of bacteria and fungus, including moulds, as the organisms responsible for onion rotting.
The fungus isolated included Mucor spp., Rhizopus spp., Aspergilus spp., and Saccharomycis spp. The bacteria identified from the sample included Staphylococcus aureus, Streptococcus pyogenes, and Bacillus spp.
Chapter One1.0 – Introduction
1.1 Background Information
Onions are an old vegetable crop that was domesticated in Central Asia. It is one of the earliest vegetables grown by humans for nourishment. Onion bulbs can be found in ancient Egypt, India, China, and Europe during the Middle Ages, and the Spaniards introduced them to the New World in the late 16th or early 17th century.
The crop is currently widely grown in temperate and tropical locations, with Europe being the greatest producer (Cobley and Steele, 1976).
In the tropics, most onions are cultivated with irrigation during the relatively cold dry season in semi-arid regions; they are not suitable for hot, humid tropics. Onions can be cultivated in a variety of climates, but they thrive in warm climates with little rainfall and little fluctuations of heat and cold.
They are not appropriate for locations with high rainfall in the lowland wet tropics. Cool circumstances with appropriate moisture supply are ideal for early growth, followed by warm, drier conditions for maturation, harvesting, and curing.
They can be cultivated in a variety of soils, but the soil must be water-retentive, non-packed, and nutrient-rich; a good fertile loam usually produces the greatest results. They can be cultivated effectively in peat soils. The optimal pH for soil is between 6.0 and 7.0 (alkaline) (Carl and Hall, 1986).
To produce a high-quality product, the onions must be stored in a certain atmosphere. Storage losses are determined by the storage environment, as well as the condition and cultural practices followed during the growth season.
Proper storage environment control, on the other hand, can greatly extend the storage season compared to storage environments that are not matched to the condition of the onions when they are placed in storage (Carl & Hall, 1986).
Onions may be stored in bulk or in palletised bins piled in a storage structure. Bins may make onion handling easier, but they also make ventilation more difficult. Improved bin design may reduce ventilation issues in the future (Cobley and Steele, 1976).
Onions are packaged locally using baskets and jute bags. These packing materials are sourced locally from palm, bamboo, and fibrous jute trees, and they come in a variety of sizes. These packaging materials serve as transportation and storage containers for onions.
Again, these packing materials are readily available and quite inexpensive. Aside from the few advantages listed, they have no dust barrier, are unsuitable for weight measurement, and are easily crushed, which may cause onion damage.
Raw onions can deteriorate due to physical reasons, enzyme actions, microbial activity, or a combination of these. Mechanical damage caused by animals, birds, or insects, as well as brushing, wounding, bursting, cutting, freezing, desiccation, or other maltreatment, may predispose to enhanced enzymatic action or microbe entry and proliferation.
Previous damage by plant pathogens may also render a portion of the crop used as food unfit for consumption, allowing saprophytes to proliferate and ruin it.
Contact with spoilt onions may result in the spread of germs that cause deterioration and increase waste. Improper environmental conditions during harvest, transit, storage, and marketing may promote deterioration.
Pseudomonas spp., Bacillus spp., chromobacterium, Enterobacterium, flavobacterium, lactobacillus serratia, staphylococcus spp., streptococcus spp., and others, as well as possibly plant pathogen species such as Erwinia and xanthomomes, are commonly found in onions.
Some microorganisms may grow between harvesting and preparation or ingestion of vegetables. Such development can be reduced with adequate temperature and humidity control (Frazier and Westhoff, 1978).
1.2 Aims of This Research Project
The objectives of this research initiative are:
1. Isolate, identify, and characterise the several microorganisms that cause onion deterioration.
2. To classify the pathogenic microorganisms responsible for onion rotting.
1.3 Statement of Problems
The civilisation consumes vegetables on a daily basis. This project research goes a long way towards identifying problems that arise when onions spoil; onion bulbs that are contaminated when consumed cause severe stomach ache (presence of enterobacteriacea) due to the pathogenic microorganisms present in them, which is hazardous to one’s health.
Pseudomonas spp., Staphylococcus spp., Erwinia, and other pathogenic microorganisms found in the rotting of onions are harmful to humans.
Onions, as a vegetable, are frequently used for seasoning and flavouring, and they are sometimes cured and preserved as a spicing agent. Proper onion storage makes it available for use all year round, and the effect of spoilage microorganisms affecting it has a negative impact on society as a whole because it makes onions less accessible to society; that is why studies are being conducted in this project research to minimise and/or stop onion spoilage.
1.4 Hypothesis.
HO-A mixed flora of bacteria and fungi is present in damaged onions.
Hi-bacteria and fungi found in onions cause the onions’ own enzymatic processes, resulting in physical, microbial, or a mix of these variables that lead to the entry and/or proliferation of microorganisms.
1.5 Significance of Study
The purpose of this project research is to identify the many microorganisms responsible for onion rotting. Bacteria and fungus were isolated and characterised throughout this process because these are the microorganisms responsible for onion rotting.
Physical reasons, enzyme activity, microbiological action, or a combination of these can all cause fresh onions to deteriorate. In terms of physical variables, raw onions can be affected by storage patterns, such as being stored in bulk or being placed in palletised bins, which does not allow for easy ventilation of the onions, therefore improved bin design may be beneficial.
In action of their own enzymes; if the raw onions are crushed during packaging and handling, this may in turn allow the penetration of micro-organisms, which will now alter the enzymatic action of the raw onions and may lead to spoilage of the onions flesh, which is meant for food and if consumed could be hazardous to health.
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