Unit 1: Food preservation and food safety. Lesson 1: Preservation

Transcription

1

2 INTRODUCTION The aim of these teaching notes is to provide guidance on how to use the activities. One of the basic aspects of teaching a curricular subject in a foreign language is scaffolding. In the following teaching notes, each unit contains scaffolding activities. Several types of scaffolding are to be found: activities, definitions, tables with grammar structures among them. Since scaffolding should be used only when necessary, in some activities scaffolding may not be necessary because students have already been helped in a similar way in a previous activity. 2

3 Unit 1: Food preservation and food safety Lesson 1: Preservation 3

4 ACTIVITY 1: THE GERMOMETER Timing: 1h Instructions Individual work Previously the teacher has explained the concept of food poisoning. In this activity, students are asked to reflect on the diagram provided. They have to answer eight questions related to it. In the first six questions they just describe what happens to bacteria in a range of temperatures. In the two last questions they have to think of a possible case of food poisoning they (or someone they know) have suffered, explain how they got it, and hypothesise on how it could be prevented. Answers key: 1. What temperature does bacteria like best? They prefer body temperature, 37ºC 2. What happens to bacteria at 63ºC? They become dormant and cannot thrive 3. What do bacteria do in a refrigerator? Their activity level is very low. 4. What happens when bacteria are put into boiling water? Boiling water kills bacteria. 5. Why is the temperature range between 5ºC and 63ºC known as the Danger Zone? Because it is the range of temperatures where bacteria are active and can reproduce 6. What are the similarities and the differences between 0ºC and 100ºC? The similarities are that bacteria cannot reproduce and are inactive. The differences are that at 100ºC most of them die. 7. Have you ever had food poisoning? How did you get it? Possible answer: Yes I have. During a party I ate mayonnaise that was contaminated with Salmonella. 8. How do you think it could have been prevented? It could have been prevented if the eggs had not have been contaminated or if the best before date had been respected. 4

5 Scaffolding Language for: At...ºC In the fridge They are similar They differ I got food poisoning Food poisoning bacteria in to from at... while being on holidays... during... could have been prevented if... could have been avoided if... feel uncomfortable are at ease are happy are sleeping are dormant don t thrive well the temperature was.. the time had been... Language through: It could have happened it could have been prevented when while because if Probably food poisoning occurred during I am pretty sure that it took place in Food poisoning could have been prevented if... avoided if... the temperature was.. the time had been... 5

6 ACTIVITY 2: THE NECESSARY CONDITIONS FOR THE GROWTH OF MICROBES Timing: 15 minutes to set up the experiment. 30 minutes to develop the report. Instructions: Pupils store uncooked and cooked rice under different conditions to determine the conditions needed for microorganisms to grow. The tubes must be checked after 1 week and after 2 weeks. Answers key: conditions in the appearance after 1 appearance after 2 tube week weeks uncooked rice no water, warm, air rice looks same rice looks the present same cooked rice alone water present, warm, air present mould starting to grow more mould present cooked rice in water present, rice looks the rice looks the refrigerator cold, air present same same cooked rice with oil water present, warm, layer of oil stops air reaching rice looks the same rice looks the same rice Scaffolding Language of: Vocabulary: Mould: thin layer on food due to the growth of fungi. Grammar Expressing past:...deterioration of the rice happened... Expressing conditional To achieve... I would do... 6

7 Language for: Possible answers for the table: rice looks the rice looks the same same mould starting to grow more mould present Giving opinions: In my opinion another preservation system would be more convenient such as... I would preserve it using... Preserving rice using boiling is/ is not convenient because...is preferable to... 7

8 ACTIVITY 3: METHODS OF FOOD PRESERVATION 1 Timing: 20 min Instructions: The students are asked to complete the mind map. To do so they have a list of words related with the process. There are more words than gaps, so they have to think about which ones to select. Answers key: 8

9 Scaffolding Language of Matching activity: this activity can be used as scaffolding for activity 3. Students are asked to match related cards in groups of three. The card containing the name has to be matched against the definition and against a drawing or picture. Oxidation chemical reaction in which a substance combines with oxygen Microorganisms microscopic organisms such as bacteria and viruses Viruses microorganisms that reproduce using the DNA of other organism 9

10 Mould multi-cellular microorganisms that form fungus (spore) which travel by air and land on food surfaces Yeasts single-celled organisms found on the skin of fruit that aid its deterioration Acidity The amount of acid in a substance sown by a low ph 10

11 Enzymes proteins that speed up reactions in our body Rotten when the flesh becomes soft Alkalinity substances that react with acids forming salts Bacteria single-celled microorganisms that reproduce by binary fission 11

12 ACTIVITY 4: METHODS OF FOOD PRESERVATION 2 Timing: 30 min Instructions: This activity helps to summarise the main methods of food preservation. The activity includes a table of preservation methods with statements which give descriptions of how the methods prevent the spoilage of food. Pupils have to match each description with the correct method. Pupils complete the table by adding examples of foods preserved by each method. Answers key: Preservation Method How does it work? Examples of foods Acidulation it becomes sour because the ph is very low Vegetables Fermentation some microorganisms can change the food composition; undesirable microorganisms vegetables, yogurt cannot grow in it Refrigeration slows down reactions meat, cheese, vegetables... Freezing slows down reactions considerably; removes water meat, fish by turning it into a solid Jellying material that solidifies to form a gel Fruits Canning and bottling destroys enzymes and most microorganisms Meat, vegetables Smoking food is exposed to the gases of the combustion of wood and meat, fish other elements Dehydration removes water completely; makes the food a solid soups, fruits, vegetables UHT it is required high temperature for a short period of time milk, cream, fruit juices Curing salt is added which makes the liquid environment very concentrated Meat Pickling adds (usually) vinegar; makes vegetables the environment very acidic adds sugar which makes the Jam liquid environment very vegetables concentrated Gas or vacuum packing removes and excludes oxygen to inhibit the growth of organisms meat, fruits, vegetables Chemical preservatives substances such as sulphur cooked meats, wine, some dioxide and sodium benzoate cheeses interfere with microbial growth Irradiation rays from a radioactive source are passed through food only herbs and spices 12

13 Scaffolding Language of: The scaffolding can be done through the matching activity of the unit 3. 13

14 ACTIVITY 5: MAKING JAM PART1 Timing: 1 hour Instructions: All the steps have been previously indicated. However the teacher must demonstrate the key points of the process, especially the most dangerous: peeling and boiling. PART 2 Timing: 1 hour Instructions: In this part the students have a jam making project. All the parts of the project have been provided and explained. This part implies use of the ICT since at the end of the project students will give a presentation of the process. PART 3 Timing: 1 hour Instructions: Students are asked to design a label for the jam jar. Using the ICT they have to look for the information needed to provide the nutritional contents. Depending on the sugar content of their jam students have to calculate the energy content. They have to make sure the label contains all the legal requirements and the design has to be appealing! 14

15 Scaffolding: Some scaffolding on the cognition and the language is provided. Cognition: In order that students have an approximate idea about how to design, an example of label with the description is shown: Brand Nutritional content Drawings Ingredients Explanation of the product benefits Language of Vocabulary: Spoon: an object with a round end and a long handle that you use for eating, mixing or serving food Ladle: a large deep spoon with a long handle, used especially for serving soup. Lids: the top part of a box, pot, etc. that can be lifted up or taken off 15

16 Language for The teacher will make sure that the students how all the necessary language to follow instructions and to express opinions. This is a table where students can practice instructions by finding synonyms: Picking Peeling Cutting Preventing Measuring Mixing Adding Testing Filling Processing Removing Avoiding Withdraw Selecting Stripping Chopping Increasing Trying Blending Putting some more Change quantity Weighing 16

17 ACTIVITY 6: INVESTIGATING PRESERVATION METHODS Timing: 40 min Instructions: Students are asked to find out which type of food is displayed, the preservation system which has been used and to write the approximate shelf life of each product. Students can search or a similar web site to find more information on the product. Answers key: Product 1: Semi skimmed milk UHT 3 months Product 3 : Probiotic Yogurt Fermentation and refrigeration 3 months Product 5: Onions Pickling 6 months Product 7: Hard cheese Fermentation 1 year Product 9: Sausages Fermentation 8 months Product 2: Skimmed milk Sterilisation 1 year Product 4: Fish Smoking 6 months Product 6: Jam Sugaring 1 year Product 8: Condensed milk Condensation 2 years Product 10: Soup Drying 2 years Product 11: Pate Vacuum package 20 days 17 Product 12: Peaches Canning 1 year

18 Product 12: Ham Curing and packing 1 month Product 13: Goats milk Pasteurisation 7 days Product 13: Tomato soup Boiling and canning 1 year Product 17: Fresh steak Vacuum packing 7 days Product 19: Vegetables Freezing 6 months Product 14: Green peppers Pickling 1 year Product 18: Chorizo Drying and curing 6 months Product 20: Cooked ham Cooking and vac. packing 15 days 1. At what temperature should chilled food be stored in a supermarket? And frozen food? Between 0 and 5ºC 2. Why does sterilised milk last longer than UHT milk? Because sterilisation kills all pathogens 3. Why do you think that the manufacturer pickles the onions instead of boiling them? Because pickling is an effective way of preserving them and there is a section in the market that demands that special flavour. 4. Ready to eat sandwiches and salads have a shelf life of only one day. If you were going to sell them, what would you need to do so as not to throw away unsold sandwiches? An effective way of extending the shelf life is refrigerating them. 5. What type of additives contains the foods in the table? Fill in the following table with your findings. Two foods have been done for you. 18

19 Food Type of Additive Name of the additive Effect 1 UHT milk No Preservatives 2 Sterilised milk No Preservatives 3 Probiotic Yogurt Stabiliser (E400) Pectina Food is thicker 4 Smoked fish Colouring Curcumin Improves appearance 5 Pickled onions Vinegar Vinegar 6 Strawberry jam Preservative (E200) Sugar 7 Cured cheese Preservative (E200) Salt 8 Condensed milk Preservative (E200) Sugar Flavour enhancer 9 Smoked sausages Preservative 10 Dried soup No Preservatives Monosodium Glutamate Sodium Nitrite Improves flavour Tastes salty 19

20 Scaffolding As a form of scaffolding students have to look up the following words in the encyclopaedia. Then they have to set up examples. Best before date: Use by date: LIST OF ADDITIVES Preservatives (E200 numbers), used to extend shelf-life of food by preventing growth of microorganisms. E.g. vinegar, salt, sulphur dioxide Colourings (E 100 numbers) Flavourings (these do not have E numbers) e.g. spices are added to enhance flavour Antioxidants (E 300 numbers) to prevent oxygen of the air affecting the food Emulsifiers and stabilisers: (E 400 numbers) Emulsifiers help oil and water to mix; stabilisers prevent them from separating Nutritive additives: used to replace nutrients lost during processing or to add food value 20

21 ACTIVITY 7: FINDING OUT MISTAKES Timing : 30 min Instructions: Students are asked to read the text and spot the false sentences and rewrite them correctly. Notice that since the sentences are not taken literally from the text, students have to make an extra effort to spot the mistakes. This applies specially with the three last ones in which students are asked to find some help from sources such as the internet. Answers key: The first use of fermentation was dates 7000 BC to produce yogurt. T/F False A: The first use of fermentation was dates 7000 BC to make alcoholic beverages. Firstly, fermentation of milk and vegetables took place in China and later was exported to the Middle East. T/F False A: Fermentation of milk and vegetables took place in Chine and Middle East simultaneously. Fermentation is not a natural process; therefore it was invented by man. T/F False A: Fermentation is not been invented by man because it is a natural process that was first observed on fruits. Bread fermentation goes as far as 5000 BC in the ancient Egypt. T/F True A: There is evidence of leavened bread in ancient Egypt One of the benefits of fermented food is that neutralises bad bacteria. T/F True A: Yes, because fermented products fight off infections. People who eat kefir are less liable to suffer heart attacks because their levels of cholesterol are lower. T/F A: Yes, because research shows that kefir decreases the levels of cholesterol, therefore there are less risk of heart attack. Among the benefits of fermented products is that people eat them can live longer and feel healthier. T/F True A: Yes, you can conclude that from the whole range of benefits of fermented products 21

22 Scaffolding Language of Research activity: this activity can be used as a scaffolding for activity 7. They learn about vocabulary, geography and history. Students are asked to search the internet and find the information they have been asked. Possible web sites to search: a) Identify in the map Ancient Egypt, Middle East, China, Georgia, Babylon. b) Currently which country is located where Babylon used to be? c) What are the alcoholic beverages? Name three. d) Why do you thing some of them contain more alcohol than others? e) What is leavened bread? f) What are the probiotics? g) Name the ten most important wine producing countries in the world. Order them according to the amount of wine produced. 22

23 Language for Structures Fermentation first happened in the year Fermentation first took place People who eat kefir are less liable to suffer Eating kefir people have less chances of of suffering Giving opinions In my opinion some beverages contain less alcohol because. I believe that the low alcohol content is due to. 23

24 ACTIVITY 8: SAUERKRAUT MAKING Timing: 2 hours Instructions: All the steps have been previously indicated. However the teacher must demonstrate the key points of the process, especially the most dangerous: peeling and boiling. The necessary scaffolding for this unit is almost identical to the one provided in unit 5 Answers key 1. Give the list of all the ingredients you have used and the necessary equipment. Ingredients: cabbage, salt, distilled water Equipment: 1 Tablespoon, 1 Large bowl, 1 Glass jar, 1 Pounder, 1 Plastic follower, Dishtowel, 1 Plastic follower 2. Explain step by step how you have made Sauerkraut. Students explain the whole process using their own words. 3. What changes have occurred with the cabbage to get the sauerkraut. A process of fermentation has taken place. Cabbage is fermented by air lactic acid bacteria. These bacteria transform sugars into lactic acid. 4. Can you think about any other method to preserve cabbage? Blanching and freezing. 5. Why do you think that the cabbage inside the jar has to be covered by brine? Because fermentation takes place in absence of oxygen. 6. In which countries is sauerkraut more popular? Look it up on Northern European countries, United States. 7. What are the benefits of sauerkraut? You can visit It is a source of vitamin C Easier digestions Isothiocyanates are anti cancer agents Sauerkraut juice is recommended for flu prevention 24

25 Lesson 2: Safety and packing 25

26 ACTIVITY 9: FOOD POISONING Timing: 30min 1. Look at the following pictures and spot the mistakes that should not be made to avoid food poisoning. 2. Write the mistakes down on the following table and explain what should be done to avoid food poisoning. 3. Explain what could happen if the mistakes are not corrected What is wrong? What should be done? Why? 1 The clean cutlery is besides the sink. Moreover the mayonnaise is out the fridge. Place the cutlery in a proper place and store the mayonnaise in the fridge. To avoid cross contamination. To avoid spoiling the mayonnaise. Bacteria and enzymes A bag of frozen food is in Place the frozen food in the develop in the frozen food at 2 the fridge. And cooked food is placed next to raw freezer and place raw and cooked food in different places higher temperatures. There may be cross contamination food. to avoid any contact. between raw and cooked food. 26

27 Eggs, mayonnaise, ham To avoid deterioration 3 and tomatoes are out of Place them in the fridge. especially the mayonnaise. the fridge. To clean up with soap and hot To avoid contamination from The table is not proper. water and to tidy up. the dirty surfaces. 4 Milk and oil are placed To place the milk in the fridge To avoid spoiling the milk and next to a heat source. and the oil in another dark the oil because of the heat. place such us a cupboard. Scaffolding Language for There is /are fresh food packages frozen food on/ in/ by/ at It should be placed on/by/ at removed stored from apart cleaned up 27

28 ACTIVITY 10: A RECIPE FOR DISASTER Timing : 1h This is a text-based activity. The aim is to highlight some of the mistakes and misunderstandings people have when preparing food. Students have to work in pairs and discuss the mistakes. Answers key: James - will prepare food whilst having a cough and cold; thus possibly transmitting bacteria by droplet infection. Gylles - has purchased dented and slightly damaged cans and foods just out of date. Rene - has purchased eggs with cracked shells and intends to use these in dishes that will be eaten raw; raw eggs sometimes contain bacteria that cause food poisoning. Anne - intends to cook some foods well before the start of the event and store them at room temperature for some time before consumption. Liz - will place the dirty dishes from the first course next to clean crockery, cutlery and raw fruit; cooked leftovers will provide suitable breeding grounds for microbes. If waste food is left near raw food for any length of time there is the possibility of cross infection. Anne - the desserts will be stored in the refrigerator on a shelf below the raw meat intended for a later event; there is great potential here for cross contamination between raw and cooked foods. 28

29 Scaffolding Language of Dented can Cough Cracked eggs Shelves Cutlery Crockery Language for Possible answers to be used: Food can be contaminated when / at / in Bacteria will grow when Cross contamination can happen when Bacteria can cause food poisoning because Food stored / kept Food should be.../shouldn t be Damaged products 29

30 ACTIVITY 11: CHECKING FOOD SAFETY AT HOME Timing: 1hour Instructions: This is a homework activity. Students are asked to make a practical application of the safety rules they have learnt in class. They have to write them in a table and check if the rules are followed. If not, they have to write the correct recommendation. Then they have to write a letter to their parents to make them aware of the rules that they have broken and make suitable recommendations. A list of all the rules students have to check and a model of the letter are given as a scaffolding. FOOD STORAGE RULES Is the temperature in the fridge set between 0 and 5ºC? Is the temperature in the freezer at least -18ºC? Is there any sign of cross-contamination? Do you store raw and cooked foods separately in the refrigerator? Are you using the oldest cans first?? Is there food under the kitchen sink? Are leftovers dated? Are they stored for less than four days? Do you refrigerate or freeze cold and frozen foods right away? Are the proper storage times for refrigerated and frozen foods exceeded? Do you space items in refrigerator and freezer so that air can circulate freely? Is fresh meat frozen immediately? Do you wrap raw meat, poultry, and seafood in separate plastic bags and set on a plate in the bottom of the refrigerator to prevent juices from dripping on other foods? Are there foods that are past the expiration date? Are food items in dry storage kept in airtight containers to prevent rodent and insect infestation? Is there any food stored alongside household chemicals? Are leftover foods stored for more than four days? Is there proper cleanness? 30

31 Model of letter: Dear Mum and Dad, At the moment I am studying food safety rules in Home Economics. We are running a campaign called Safer Homes. I have learned that safety rules have to be followed to avoid food poisoning. As a class activity I have to check the safety rules in our kitchen. I have found that: The temperature in the fridge is 6ºC which should be 5ºC at maximum. There was cooked food under some raw meat which can cause crosscontamination. There were two tuna cans which were dented. They should be removed because they can be contaminated I hope you will correct these mistakes so we can be safer at home. Your son/daughter (Your name) 31

32 ACTIVITY 12: INVESTIGATING ON FOOD POISONING Timing: 1 hour Students are asked to read the food poisoning facts and to reflect on it. Instructions Answers key: 1. The students can use an electronic sheet to draw the diagram. Then they will conclude that the diagram follows a step increase. 2. The students have to discuss the reason. A possible reason is that most cases of food poisoning are not critical. 3. People are used to buying in bulk which makes breaking safety rules more dangerous. 4. Salmonella and paratyphoid. Symptoms: headache, vomits, diarrhoea. 5. Students have to review the class notes and fill in the table. 6. Because the cooking process is done properly in the whole chicken. 7. To avoid cross contamination from the raw to the cooked food. 8. To avoid the growth of bacteria. Students can explain what happens in the germometer. 9. Name the basic food safety rules. 10. Because bacteria can grow in the process of thawing and freezing. 11. They can survive temperatures above 70ºC 12. They have to study the diagram and find out what has to be done in the marked steps. They can discuss what should be done. Some sort of scaffolding should be provided if necessary. 1 and 2 watch out for animals that show signals of illness and separate them from the rest. Put the rest of animals under quarantine. 3 carry out proper analysis. 5 To cook food enough. 6 Avoid contact between raw and cooked meat. Scaffolding Language for In my opinion what should be done is to remove/ separate /eliminate I believe that the management is faulty The matter is that the process should be checked /inspected/ avoided What is wrong is 32