"Slowing down the speed of food spoilage" Food PPT courseware 2

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"Slowing down the speed of food spoilage" Food PPT courseware 2

People depend on food

We eat a lot of food every day, who can tell you what you like best?

The teacher also has many favorite foods. Please take a look at the teacher’s favorite foods!

1. Observe spoiled food

1. Have you ever eaten dried fish? How does it taste?

The taste of dried fish: delicious, delicious, delicious, etc.

2. What are the differences between fresh food and spoiled food?

think about it

1. What are the similarities between rotten fish, sour noodles and moldy bread?

The taste changes, basically it becomes sour and smelly, and the food changes color, grows hair, and becomes rotten. These are the basic characteristics of food spoilage.

2. Why does such fresh food deteriorate after being stored for a period of time?

The main reason is microorganisms causing trouble. As long as the temperature is suitable, microorganisms will grow and reproduce, decomposing nutrients in food to meet the needs of the microorganisms themselves. At this time, the protein in the food is broken down into organic acids and other substances. At this time, the material will have an ammonia odor and a sour smell, and the food will also lose its original toughness and elasticity, and the color will be abnormal.

2. Various methods of storing food

1. We already know that certain air, moisture, temperature and other conditions are required to cause food to spoil. If you want to store a fresh small fish, what method can be used?

2. Discuss in groups and explain the reasons for using this method to store food.

3. Why can food stored in cans extend its shelf life?

4. What other methods do you know about storing food? Why do these methods slow down food spoilage?

5. Discussion: What other ways can you use to store food?

Is the following statement correct?

1. Food spoilage is caused by the proliferation of microorganisms.

2. The growth and reproduction of microorganisms require air, moisture and suitable temperature.

3. When you smell spoiled food, fan it and smell it as little as possible.

4. Freezing, drying, vacuum packaging and other methods can slow down the rate of food deterioration. The reason for this is the destruction of the conditions required for microbial growth.

Helping others

Today Xiaohong went to the supermarket to buy things with her parents. She saw a lot of food. Can you help her identify how these foods are stored?

talk

Students: What knowledge have you learned through studying this class?

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For more information about the PPT courseware "Food Slows Down the Speed ​​of Food Spoiling", please click on the "Food ppt Slows Down the Speed ​​of Food Spoiling" ppt tag.

"Slow down the speed of food spoilage" food PPT download:

"Slowing down the speed of food deterioration" Food PPT download Part 1: Introduction of new knowledge There are often some foods in the pantry and drawers at home. How can we preserve food for a long time without deteriorating? ... ... ... Slow down the speed of food spoilage PPT..

"Slow down the speed of food spoilage" Food PPT:

"Slowing down the speed of food spoilage" Food PPT Part 1: Observing spoiled food Observe a fresh dried fish and fresh dried noodles. What are the characteristics of fresh food? Observe a small fish that has begun to rot and noodles that have gone sour. spoiled food..

"Slowing down the speed of food spoilage" Food PPT courseware 3:

"Slowing down the speed of food spoilage" Food PPT Courseware 3 Scientific Concept Food spoilage is caused by the massive proliferation of microorganisms. Microbial growth and reproduction require conditions such as air, moisture and suitable temperature. Destroying the conditions for microbial growth and reproduction can slow down food spoilage.

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Update Time: 2024-07-30

This template belongs to science courseware Fourth Grade Science Volume 2, Textbook Edition industry PPT template

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