ISOLATION AND IDENTIFICATION OF MOULDS ON BAKED FOOD (BREAD AND CAKE)

1.0 Introduction

1.1 Background of the Study

Food spoilage by mould is a natural problem occurring more or less frequently depending on the nature of food and the environmental conditions, in addition to the economic consequences of mould growth. Some fungal species have been proven to produce mycotoxins in food, which may constitute a potential health hazard for the consumer (Alan, 1999).

Baked food such as bread, cake are the most staple food in the world. These food are spoiled by moulds especially Penicillin species, Aspegillus species. However, the dominant spoilage mould depends on the type of bread and the storage temperature. Mycotoxigenicmould can be isolated from spoilage breads, and many mycotoxins have been produced in inoculated breads, but survey of naturally moulds breads have yielded afflotoxin and Ochrotoixn A in few samples of baked food (Kroll, 1993). Mould growth in baked food bread and cake can be reduced by a range of techniques which includes: proper hygienic within the bakery to reduce the opportunities for mould spores to gain access to the product, pasteurization of bread once packaged, use of preservatives which reduces or prevent the growth of moulds (Samuel, 2000).Food can be contaminated with spoilage on pathogenic organisms ( micro). Infestation of these moulds spoil the product so that it is not fit to eat; it also changes the taste so that the product is not desirable.

The concept of food infestation of moulds is based on the consipteration for fiutres of consumption. Infestation is defined as the over presence alone has led to its growth and microbial activity. Pathogenic organisms however can cause food poisoning. Food poisoning can arise through infatuation of food by organisms (micro) which secrete toxins which B their consumed. The cost of fungal infested bread resulting to spoilage is also great with loss of money due to wastage of the raw materials. Also considering the usefulness of this product in the community with the management of money being spent it has also helped in the sense that since it is regarded as a fast food it is being bought and consumed directly without further preparations done. Effect of contaminated bread in the society can lead to an epidemic of gastrointestinal disorder where by that particular environment that consumed the contaminate bread become affected there by developing stomach upset. As a result of this a lot of consideration should be given to breads that are sent into the community to be sold and this is done by the standardized system called HACCP ie hazards Analysis critical control point.

This method is now generally considered as a choice for ensuring safety of foods (jay 1996 de Boer and Beumer 1999) hazzard analysis critical control point involves identifying places in the production process where hazzard could occur. i.e. The CCp (critical control point and putting monitoring procedures in place to prevent these hazards occurring even with this system in place samples still need to be tested for the presence of microorganism.

Detection of most of the microorganisms requires growth of the organism on selective media which can take a number of days from isolation to identification.

These method are sensitive and gives qualitative information on the number and nature of the microorganism. Present in a food sample. However, conventional methods require several day to produce result because they rely on the ability of microorganisms to multiply to visible colonies (De Boser and Beumer 1999). Presentation of bread commonly involves the use of propionates and sorbates and sometime henzoates. Preservatives are added to retain on to increase the shelf life by preventing the micro-organism responsible for the contamination of that food. There alter natives to preservatives have been bought also. The chief types of microbial spoilage of bread as a result of fungal infestation will also studied which is moldiness. Rapines is also another type of bread spoilage but unfortunately it wont be studied due to the fact that it is caused by bacterial organism which unfortunately is not a fugal organism and as a result is not in the scope of study for this research work. Also a spoilage not so common called CHALKY BREAD caused by a yeast like Fungi, will be diseased.

Bread is one of the important staple foods in most countries. It is prepared by baking dough primarily composed of flour and water. The combinations of different flours and ingredients such as salts, fats, yeasts, eggs, sugars, spices, fruits, vegetables, nuts and seeds have resulted in the wide variety of types, sizes and textures. Bread is an important source of carbohydrates, proteins, lipids, vitamins, fibers and minerals.

Bread may be served in different forms at any meal of the day, eaten as a snack and is even used as an ingredient in other culinary preparations. As a basic food worldwide, bread has become significant in religious rituals, secular cultural life and languages. Bread is prone to spoilage problems. These include physical, chemical and microbial spoilage. Mould growth is the major economic importance of bread and is a serious and costly problem for bakeries and consumers. The moulds involved in the spoilage of bread include Rhizopussp, Penicilliumsp, Eurotiumsp, Aspergillus sp and Moniliasitophila. One of the most common is Rhizopusstolonifer, often referred to as the bread mould.

Economic losses of bread due to mould spoilage are between 1% and 5% depending on the type of product, season and the method of processing. In addition to the economic losses associated with bread, another concern is the possibility of mycotoxins production by some moulds. The concentration of nutrients also determines the rate of mould growth in bread. The growth of mould in bread is a substrate-saprophyte relationship with the bread providing nourishment and the mould surviving on it as long as favourable environmental conditions prevail.

Mould growth in bread is also favoured by their ability to synthesize proteolytic and amylolytic enzymes. Furthermore, moisture condensation on a bread surface due to packaging while the product is not completely cool, may be conducive to mould growth.

The aim of this study was to isolate, characterize and identify the filamentous fungi associated with the spoilage of commercial bread in Enugu, Nigeria so as to educate the consuming public on the danger inherent in the consumption of such spoilt bakery product.

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1.2 Statement of Problem

A major causes of growth of mould in baked food (Bread and cake) is long storage. Baked product being food consumed, entails large purchase from bakery, and at times the sellers do not finish the sale within a week. These long storage causes growth of mould, resulting to food poisoning as a result of the toxins produce by these mould infected bread.

Research conducted shows that people especially in rural areas consume mould infected bread and also the prevalence of food borne disease is high in these area. Problems encountered by the society as a result of the consumption of contaminated bread infested with mould art circulation in the market places are related health wise, in the sense that when contaminated. Breads are eaten; it leads to caster or intestinal disorder by some mould which is a result of deposited toxins. This can lead to an epidemic, when a batch of count ammoniated breading in circulation.

Problems due to spoilage yeasts in bread usually result from post-baking contamination. Yeast spoilage is characterized by visible growth on the surface of bread. Wild yeast such as Trichosporon, Saccharomyces spp, Pichia and Zygosaccharomyces can also cause spoilage of bread. Saccharomyces spp produce white spots in bread leading to the term Chalk bread. Yeasts that cause problem in bread can be divided into the wild yeast which grows on the surface of the bread in white and pinkish patches and fermentative yeast which are associated with alcoholic and essence odours. Yeasts are however not more common in bread than filamentous fungi.

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1.3 Aims and Objectives of the Study

This project is based on the isolation and identification of moulds on baked food (bread and cake). To examine the species of mould that infest bread at room temperature.

Given below are the specific objectives of the study

1. To identify the mould responsible for spoilage in baked food (Bread and cake)
2. To isolate moulds in the product (Bread and cake).
3. To know the effect of the mould implicated in bakery foods (Bread and cake).

1.4 Hypothesis

H0 filamentous fungi and yeast has no effect on bread .

H1 filamentous fungi and yeast are responsible for spoilage of bread when infested.

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1.5 Significance of study

The isolation and identification of mould in baked product would provide a knowledge of the effect of mould on the baked product, these would thereby improve the needs to preserve baked foods (Bread and cake), and reduce the rate of food poisoning from consumers of the product.

The justification of this research study is to ensure that a well prepared baked bread devoid of fungal growth is being circulated on sold. It is also carried out on the basic of selling well baked breads uncontaminated so as to avoid any dont of food poisoning associated with the ingestion of bread.

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1.6 Scope of the study

This study focused on bakeries in Enugu. This project work is limited to the isolation and identification of moulds on baked food (bread and cake). This is also limited restricted on the examination of the end product which is the baked bread and not its raw material which is the flour, practical works is carried out on the pathogenically of species identified as this could be another area of study for interested microbiologists.

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1.7 Limitations of the Study

Lack of finance limited the scope of the project work, as it interfered in the sourcing for information, and also it affected the practical work as there was not enough money to purchase some laboratory materials that are non-existence.