microorganism associated with spoilage of tomatoes (canned tomatoes)

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Chapter one

1.0        Introduction

Chapter Two

2.0        Literature  review

2.1    History of canned tomato

2.2    Types of canned Tomatoes

2.3    Nutrition facts of canned tomatoes

2.4    Common additions of canned tomato

2.5    causes of canned tomatoes spoilage

2.6    Control/preservation of canned tomato

Chapter Three

3.0        Materials  and Methods

3.1    Place of experimental work

3.2    materials used

3.2.1 Reagent used

3.3    Collection of sample

3.4    Medium preparation

3..4.1        Preparation of nutrient agar

3.4.2 Preparation of potato dextrose agar

3.5    Sample preparation

3.6    Microbiological Analysis of the Sample

3.6.1 Determination of analysis load (bacterial and Fungi Load)

3.7    Preparation of pure cultures pf Isolate (bacteria and fungi)

3.7    Identification of bacteria isolates

3.7.2 Colonial or  cultural characteristics

3.8    Gram Staining

3.8.1 Indole test

3.8.2 Motility Test using stab cultures techniques

3.8.3 Methyl Red (Mr ) Test

3.8.4 Volies –proskader (VIPs) test

3.8.5 Identification of fungi

3.9    Microscopic Examination

3.10  biochemical Reactions

Chapter Four

4.0        Microbial Load or bacteria Associated with canned Tomato  spoilage

4.1    Discussion

4.2    Conclusion

4.3    Recommendation



The micro-organism, associated with spoilage of tomatoes shows that tomato contain large amount of water which makes them more susceptible to spoilage by the action of various micro-organism. Out of  the (3) three sources of samples used in the assessment revealed that Bacillus species identified in the spoiled sample are  the major causes of canned spoilage while the fungi isolates are peniucillum species etc which revealed by the assessment are also the cause of  tomato spoilage. In this  assessment carried out,  it was  found out that bacterial species were the source of spoilage rather than bacteria because it dominated all the plates.



Canned tomatoes are tomatoes usually peeled that are sealed into a canned after having been processed by heat.

This product are considered important world wide (Robinso, et al, 1994). In Nigeria tomato paste is the most important  tomato  product  because of its wide spread use for preparation of various food/menus. It contain on the average about 6.4% total solids, of which 3.5% is invert sugar, 0.5% citric acid,0.6% ash, 0.9% protein, 0.53% crude fibre and about 0.05% fat. When spoil as a result of the life processes of bacteria, yeast and molds, the sugars are  rapidly used up being changes into acetic  acid, lactic acid, alcohol and carbon dioxide, the amount of these substances depending  on the types of organism which are most  active in the particular sample in question.

Until recent  years, nearly all the tomato paste consumed in Nigeria was important from European countries with Italy being the leading country. However, today, limited brands are produced locally. Although both the imported and the local brands are available on the market, consumers prefer the former  in spite of its relatively  higher cost.

In general, adequate heat processing is given to tomato paste to achieve commercial  sterility (speck, 1984), but subsequent abusive post-process handling/storage may lead to undesirable microbiological changes  (Anon, 1980). It is public knowledge  that can of tomato paste often show external evidence of spoilage under tropical retail conditions. In addition, and interestingly, these d effective products are sold (especially to the less informed) at the same cost as the normal (non-defective- product.

The structural   systematic approach for the control  of food safety “Hazard Analytsis and critical control point-HACCP” identifies, evaluated and controls hazards that are significant for food safety. The control parameters include various factors  such as  time of harvesting, temperature and moisture during storage, selection of agricultural products prior  to processing, decontamination conditions, addition of chemicals at final product storage ((Sango, 1995).


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