Laboratory work on the biology of mold on bread. How to grow mold on bread at home

For mold to appear, it is enough to leave the product open for several days, and it will not be slow to appear. But if it needs to be grown in a short time, then a certain environment must be created for its growth. Before you grow mold, you need to stock up on one of the following ingredients, namely agar-agar, jam, bread, tomato paste, potatoes, sour cream, pickles and blue cheese.

Methods for growing mold

• Agar-agar. Labs use agar-agar to grow mold. The same can be done at home. Unpeeled raw potatoes should be cut into cubes, and boiled over low heat for thirty minutes. After that, the broth is filtered and put on fire again, but only with the addition of agar-agar, which is sold in any store. After the powder has dissolved, the mold breeding medium will be ready. Now you need to wait until the mold itself starts up in agar-agar, but you can bring it from any other product so that it grows faster.
• Bread. Surely everyone knows that mold often appears on stale bread. Therefore, if you want it to appear on it, then before you grow mold on bread, you need to sprinkle it with water and wrap it in a plastic bag. Also, bread must be put in a warm room where the sun's rays do not penetrate. After that, it remains only to wait for the mold to appear. If you want to grow black mold, then you should buy white bread for this purpose.
• Other food items. If the above methods do not quite suit you, then mold can be grown in one of the following products: in a jar of pickles, with jam or tomato paste. Before you make mold in these products, you need to stir them with a dirty spoon, after which you should close the jar tightly and put it in a warm place. Very soon you will be able to watch her seedlings.
• Blue cheese. In addition, the mold can be diluted with the help of mycelium, which is the vegetative body of fungi and actinomycetes. To do this, take a piece of blue cheese, pour sour cream over it, and leave it all at room temperature. Do not hesitate, soon you will see whole plantations of mold. Don't be upset if your mold turns black. These are just ripe boxes with spores that are at the tips of the mycelium. Once they open and scatter these spores around, your mold growth will increase significantly. Now you know how to grow mold in the quantities you need.

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Relevance.

I wondered why mold appears on food and decided to find out what mold is? Is mold harmful to humans? How is it formed? To answer these questions, I decided to do research.

Introduction.

Mold and mold fungi covertly accompany us throughout the history of human existence, and it appeared much earlier than man himself. Despite a lot of scientific research, the active development of microbiology, rich statistical experience, mold remains one of the mysteries of our world, has not been fully studied and appears every time in a new quality. She kills and saves from death. In a clean room, every cubic meter of air contains up to 500 fungal spores. Larger ones can cause allergies, small ones can cause lung diseases, migraine, otitis media, bronchitis, rhinitis, and asthma. Finally, mold toxins can accumulate in the body and lead to liver cancer. Of course, this is not the type of fungus that is used in the preparation of elite varieties of cheese and wine. The difference between them is like between a toadstool and a noble white fungus. Opening a jar of jam, where a whitish film appeared on top, or cutting off a greenish coating from a loaf, you are at great risk. Such a product is already completely affected by mold spores. You must immediately throw it away and try not to even breathe next to it. This micro-enemy is ready to use the slightest oversight to penetrate our body and try to destroy it.

Mold is harmful and beneficial.

Mold

"harmful" "beneficial"

Composition of dangerous mold.

I examined what mold is and found out that the first is useful, and the second is dangerous. I want to dwell on dangerous mold in more detail.

Mold- These are microscopic fungi, there are over 300 thousand of their species. Each mushroom is a long thread and usually consists of three parts: - a root that penetrates deep into the food if it can, and which is often not visible to the naked eye; - stem or branches that are visible on the surface; - spores that form at the ends of branches.

Mold color is determined by spores. They are also carried through the air and in contact with other objects.

What products can be saved from mold

But there is no rule without exceptions. For example, with salami and dried ham, the mold can simply be scraped off and used as food, as if nothing had happened. The same applies to hard cheeses - cut off the surface with harmful mold with a knife and about 2-3 centimeters of cheese "deep", throw them away, and feel free to eat the cheese itself. You can use, after cutting off the same 3 centimeters, hard vegetables like cabbage, carrots or potatoes.

Scientists and mold.

The mess in Fleming's laboratory served him well. In 1928, he discovered that on agar in one of the Petri dishes with bacteria Staphylococcus aureus a colony of fungi has grown. Colonies of bacteria around the molds became transparent due to cell destruction. Fleming managed to isolate the active substance that destroys bacterial cells - penicillin, the work was published in 1929. Fleming did not expect pure penicillin to be so difficult to obtain. His work was continued by Howard Florey and Ernst Boris Chain, who developed methods for purifying penicillin. Mass production of penicillin was established during World War II. In 1945, Fleming, Flory, and Chain were awarded the Nobel Prize in Physiology or Medicine.

Mold - MUCOR.

Mukor(lat. Mucor), Also white mold- a genus of lower mold fungi of the class Zygomycetes, which includes about 60 species. They are widely distributed in the upper soil layer, and also develop on food and organic residues. Some species cause diseases (mucormycosis) in animals and humans, others are used to produce antibiotics or as a starter (since some mucosal fungi have high enzymatic activity). The mycelium is not divided by partitions and is represented by one giant multinucleated branched cell.

Practical work No. 1

Subject: Growing mold mukor at home.

Target: I want to see for myself how mold appears and grows on food.

Progress:

Vegetable preparation.

Growing mold on bread.

Infection of pumpkin with mold.

Monitoring the process of mold growth.

Examining mold under a microscope.

Back in the last academic year, my teacher Angelina Nikolaevna suggested that I conduct this research work on a vegetable. With the help of my grandmother during the summer holidays, I grew a pumpkin.

Then I put a few pieces of bread in bags and put them in a dark place in the kitchen.

A week later, they got mold.

My next step was to infect the pumpkin with mold. Wearing gloves, I made a small hole in the pumpkin with a knife. I rubbed the mold on the bread on a cut in a pumpkin and left it for a week.

In three weeks.

Conclusion: I did my research work for 37 days, plus time to prepare it.

I myself at home managed to grow mold - mukor. I examined it carefully under a microscope.

I came to the conclusion:

Moisture, heat, lack of ventilation are necessary for the development of mold. The higher the air temperature, the faster the appearance and development of mold. Dry air and low temperatures are the main barriers to mold growth. Having conducted experiments, I can safely say that mold appears if there are factors such as heat, moisture and no ventilation. Molds are dangerous to human health.

Conclusion.

Mold- These are microscopic fungi, there are over 300 thousand of their species. Each fungus is a long thread and is usually made up of three parts - the root, which penetrates deep into the food if it can, and which is often invisible to the naked eye; - stem or branches that are visible on the surface; - spores that form at the ends of branches.

In carrying out this research work, I studied a lot of literature containing information on this topic. In the course of the experimental part of the work, it was proved that the rate of mold growth depends on the following conditions: on air humidity and on ambient temperature, on products on which mold grows. I found out the importance of mold for human health and its impact on the ecology of the home.

Cover cooked food with cling film to protect it from airborne mold spores. Pour perishable food from open cans into clean containers and refrigerate them immediately. Do not leave perishable food out of the refrigerator for more than two hours. Keep leftover food for no more than 3-4 days to prevent mold from growing.

How to deal with moldy products?

Don't give mold a chance.

Do not buy a lot of products and do not store them forgery.

But what if something got moldy? Do not smell moldy product! This can cause respiratory problems.

If a food item is covered in mold, discard it by wrapping it up or placing it in a small plastic bag.

Throw away! moldy products only in closed garbage containers.

Immediately clean the refrigerator or cupboard where the moldy product has been.

Check nearby food. Mold quickly spreads to vegetables and fruits.

List of used sources and literature

1. Kudryashova A.A., Dedyukhina V.P. Microbiology, Sanitation and Hygiene: Publishing House of the Far Eastern State University of Economics, 2003.

2. Rabotnova I.L., General microbiology, M., 2001

3. Ismailova S. Encyclopedia for children v.2 Biology. M Avanta+, 1995

4. http://commons.wikimedia.org/wiki/Mold.

Usually they try to get rid of mold and generally prevent its occurrence in advance. But the thirst for knowledge can push young and quite mature naturalists to unexpected experiments. For example, to grow mold at home. Although most often such an idea does not come to them by itself, but is a practical task in biology, chemistry or other natural science disciplines. And then schoolchildren and students are taken for this experience, which, in general, is not at all difficult to implement. You just need to have the right materials and at least a basic understanding of the ongoing process.

Where does mold come from on bread?
Mold is a generalized name for many genera of fungi, the fruiting bodies of which can develop in almost any nutrient medium. In everyday life, we most often meet mold fungi on finishing materials and food. For example, in the bathroom or on the remnants of dinner left on the kitchen table until the morning. Some of them people have learned to subordinate to their needs and use in the production of medicines (penicillin, streptomycin), products (roquefort cheese, camembert, brie) and drinks (sherry). Others have remained toxic pests that poison agricultural stocks and cause pathologies in the human body.

As for the "bread" mold, it is a direct species "relative" of just penicillin fungi. For their reproduction, they choose warm, humid environments rich in carbohydrates. Therefore, fruits, potatoes and bread are ideal foods for mold to develop. They quickly form a white, greenish, gray, pink or even black coating - depending on the type of fungus. Food spoilage can be prevented by proper storage and timely use before the expiration date. It is also important to prevent excessive humidity and ventilate the room, keep it clean - all this prevents the development of mold. But in our case, we will have to act just “on the contrary” and create optimal conditions in which mold fungi will readily multiply.

Growing mold on bread
Laboratory studies suggest the use of agar-agar as a nutrient medium for mold. But, since bread is indicated in the conditions of our problem, we will use it. It is not necessary to go to the bakery for some special variety - any available in a home bread box will do. Unless, for the sake of completeness of the experiment, you can take both a wheat loaf and a rye brick, and at the same time a rich bun, supplementing the set of exhibits with unleavened lavash. But this will practically not affect the course of the experiment, so let's just get down to business:

1. Take a piece of bread, consisting of a crust and crumb, sprinkle with water and put in a whole plastic bag (it is better to choose a transparent one for this purpose, through which it will be easy to see all the changes). In principle, there is enough moisture in the bread, but additional moisture will speed up the process of mold development. Tie the bag tightly and put it in a dark place (a kitchen cabinet or a plastic bread box is ideal). After a couple of days, you will notice the first signs of moldy bread. At first, these will be whitish and/or light gray spots on its surface, then they will become larger and gradually cover the entire surface of the product. Do not interrupt the experiment and wait a couple more days. The mold will turn green and then darken and eventually turn completely black. This means that the fungi live so well and freely that they decided to increase their colony by forming microscopic boxes containing spores on the processes of the mycelium. As they mature, they open up and scatter fungal spores around them, thereby "prolonging the genus" of the fungus. So, if the mold in your experience has developed to this stage, then you can proudly consider yourself an experienced naturalist. Or, at least, pass the practical work as "excellent".
   
2. You can complicate your task by making the experiment more visual at the same time. To do this, just like in the first case, take a piece of bread. Then wet a textile or thick paper towel, wring it out well (so that it is not wet, but only damp) and place it on the bottom of a glass jar with a lid. Put the bread on top of the napkin and close tightly. The presence of wet tissue will accelerate the development of molds, and the glass walls of the jar will allow you to observe this process. Most likely, visible changes will occur no earlier than on the second or even third day of the experience. But then events will develop faster. Mold spores grow and increase in size, change color (from white-gray to greenish-yellow). Gradually, it will cover the entire piece of bread and turn black.
   

Please note that it is easier to observe the process of molding white bread, because on its surface the colored spots of fungi stand out more contrast and therefore are noticeable immediately after the appearance. If you want to speed up the course of the experiment, provide humidity and heat, if you want to slow it down, then vice versa. All this can be described as an accompanying text for a practical task, which will definitely have a positive effect on its assessment.

Interestingly, factory-made bread brought from the store becomes moldy faster than homemade bread baked in a bread machine or oven. This is not difficult to verify, but can be explained by several reasons. But the most likely of them is the infection of bread with a mold fungus during production in the factory workshop or during transportation. In other words, the microflora of industrial food products does not always meet sanitary standards.

By the way, unleavened bread molds faster than buns and other sweet pastries. Perhaps it's all about preservatives and flavorings added to confectionery. But the fact remains: molds are reluctant to use them as a nutrient medium. We hope that this information will be enough to develop basic research skills and gain valuable practical experience. In everyday life, it can be useful in order to, based on the information received, properly store and eat only fresh, mold-free products.

Stock up on everything you need. To grow mold on bread, you will need the following materials: a slice of bread (any variety will do), a resealable plastic bag, a spray bottle, and water. Any type of bread can be used, but be aware that some long shelf life varieties contain preservatives that will slow mold growth. Mold grows faster on fresh bread.

• Although you can do without a spray bottle, it will help to evenly moisten the bread with a small spray of water.
• Before starting the experiment, fill the bottle with water.
• If you don't have a plastic bag, you can use any transparent, tight-fitting container instead. Tightness will prevent mold from getting out, and transparency is necessary so that you can watch the growth of mold. An old plastic or glass jar will do.

Spray bread with water. Take a spray bottle and lightly spray the bread with water. The bread shouldn't get wet - just spray some moisture on it to encourage mold growth. It is enough to spray it once from the sprayer.

• You can create a humid environment in other ways:
  • Put a damp towel in a plastic bag along with the bread.
  • Sprinkle water only on the tip of the bread slice.
  • Spray water inside the bag, not on the bread itself.

Seal the bread in a plastic bag. Put the slice of bread in a plastic bag and close it tightly. During the entire experiment, you should keep the bag closed so that the spores of the mold that you grow on bread do not leak out of it.

• If you are allergic, this test should not be performed as it may cause complications.

Put the bread in a warm, damp place. Mold grows well in a warm environment with high humidity. Choose a warm place in the house and put a bag of bread there. You have already created the increased humidity inside the bag.

• Mold doesn't need sunlight to grow, it gets the nutrients it needs from bread. That is why mold often grows in dark, damp places (for example, in basements).

Watch for mold growth. Check bread daily and watch for mold growth. It should take about 7-10 days before you notice obvious signs of mold. On some types of bread, mold can appear as early as 5 days. Keep in mind that mold develops faster on fresh bread than on those varieties that are intended for long storage and therefore contain preservatives.

• If you notice that the bread has dried out, add some more water to the bag. Before opening the bag, put on rubber gloves and a face shield to protect yourself from mold spores.

Mushrooms are very ancient organisms that appeared on Earth at the end of the Mesozoic (more than 185 million years ago) - the deposits in which the remains of fungi are found date back to this age. Many scientists believe that fungi originated from algae, others believe that they had common ancestors from primitive groups, such as flagellates, with algae.

Mushrooms have captured the entire planet - from the harsh polar regions to the tropics, they are found not only in meadows, forests, mountains, but also in swamps, deserts, cities and even in reservoirs, their spores are found on the glaciers of Antarctica and in the atmosphere.

Not all mushrooms form large fruiting bodies. The living conditions of fungi are extremely diverse. Some live in our homes, but for the time being and for the time being we do not notice them. These include white fluffy mold.

Option 1

Leave pieces of white or black bread in the bread box for several days. They will be covered with spots of white, yellowish or green mold. Molds settle on bread, jam and other products.

White fluffy mold is often a mucor fungus. Like all mushrooms, mucor does not have chlorophyll and feeds on ready-made organic substances. He finds suitable conditions on food products.

Option 2

Place 2-3 layers of filter paper on the bottom of the Petri dish.

Pour a little water on the filter paper to make the paper damp.

Put a piece of white bread in a Petri dish on filter paper, and then cover with a beaker.

Place the Petri dish in a warm place (20-25°C) for several days. Keep the filter paper damp.