13043729
Description
Flashcards by Mrs Z Rourke, updated more than 1 year ago
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Created by Mrs Z Rourke
about 6 years ago
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| Question | Answer |
| What food and drink products are made using microorganisms? | Beer Wine Yoghurt Cheese Bread |
| What microorganism is required to make bread, beer and wine? | Yeast |
| What is the role of the yeast when making bread, beer and wine? | Yeast ferments |
| What microorganism is required to make yoghurt and cheese? | Bacteria |
| What is the role of the bacteria when making yoghurt and cheese? | bacteria breaks down lactose (a sugar in milk) to form lactic acid |
| What is the word equation for fermentation? | |
| What type of respiration is fermentation an example of? | Anaerobic respiration (without oxygen) |
| Between what temperatures do the enzymes in yeast work best? | Enzymes in yeast work best at a temperature between 15 degrees Celsius and 25 degrees Celsius when no oxygen is present. |
| What are the stages to making beer? | 1. Malted barley grains are mixed with warm water 2. Starch in the barely is converted into glucose 3. Hops are added for flavour 4. The liquid (called wort) is boiled 5. The wort is cooled, and run into the ‘mash tun’ 6. Yeast is added to the mixture 7. Fermentation begins when the oxygen runs out 8. Fermentation stops when all the maltose is used up 9. The beer is bottled or put into barrels |
| What are the stages to making yoghurt? | 1. Pasteurise the milk by heating 2. Add the bacterial culture to the cooled milk 3. Leave at 46 °C for about 4 hours 4. Sample to see if the yoghurt is ready 5. Add flavour and colouring 6. Packaging of the yoghurt |
| What sugar does milk contain? | Lactose |
| What do bacteria break the lactose down into? | Lactic acid |
| What is the role of the lactic acid in the process of yoghurt making? | The lactic acid curdles the milk and lowers the pH of the yogurt which helps to preserve it. |
| What are the stages to making cheese? | 1. Add bacteria and rennet to milk 2. The milk curdles and separates into curds and whey 3.Drain off whey 4.The curds (milk solids - fats and proteins) are pressed to make cheese solid 5. The cheese is left to mature to improve its flavour and consistency |
| What conditions need to be considered for efficient growth of bacteria? | Suitable temperature, moisture and food source |
| What is pasteurisation? | Foods are exposed to high temperatures to slow bacterial growth |
| What drinks are subjected to pasteurisation? | Beer, milk and fruit juice |
| How is pasteurisation used in milk? | Pasteurisation involves heating milk to 72°C for at least 15 seconds. Once the milk has been heated, it is then cooled very quickly to less than 3°C and packaged for selling. |
| What is homogenisation of milk? | Commercial milk is also usually homogenised. This is done by pumping milk at high pressures through narrow tubes. This breaks the fat globules into smaller droplets so that they stay suspended in the milk rather than separating out and floating to the top. |
| How is semi-skimmed and skimmed milk produced? | Sometimes the amount of fat is reduced before the milk is homogenized. This is done by skimming fat off the milk. |
| When does pasteurisation of milk take place? | Milk is normally pasteurised after it is homogenised. |
| How can you slow down or stop bacterial growth? | • refrigeration – slows down but does not stop bacterial growth • freezing – stops bacteria multiplying but does not kill them • heating – heating then rapid cooling kills nearly all microorganisms • cooking – kills microorganisms • drying – removes water so bacteria cannot digest and absorb the food source • salting – bacteria lose water from their cells so they dehydrate and cannot reproduce • pickling – addition of vinegar to lower pH and inactivate microorganisms. |
| What precautions need to be put in place to keep food areas free of bacteria? | • good personal hygiene • wearing protective clothing • use of disinfectants on surfaces • using detergents to wash up • sterilisation using high temperatures or gamma rays • correct disposal of waste • control of pests such as insects or mice |
| What are the symptoms of food poisoning? | Common cases of food poisoning will typically include at least three of the following symptoms: • feeling sick (nausea) • vomiting • diarrhoea • stomach cramps and abdominal pain • a lack of energy and weakness • loss of appetite • a high temperature (fever) • aching muscles |
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