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21 Cards in this Set
- Front
- Back
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How is the O2 supplied in the vinegar process?
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It is furnished by exposing inoculated raw material to air by arranging it in thin layers in open trays, allowing it to trickle over loosely packed beechwood twigs and shavings, or aerating it in a vat.
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What is the chemical equation for production of acetic acid?
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2C2H5OH(ethanol)+1/2 O2------CH3CHO+H2o(acetaldehyde)
CH3CHO+1/2 O2(acetaldehyde)---- CH3COOH(acetic acid) |
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Milk in the udder of the cow is a sterile substance, but as it passes out of the teat, it is inoculated by the animals normal flora. TRUE/FALSE
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TRUE.
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What happens to raw milk when left at room temperature?
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A series of bacteria ferment the lactose, produce acid and alter the milks content and texture. This progression can occur naturally, or it can be inducedc as in the production of cheese or yogurt.
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What happens in the initial stages of milk fermentation?
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Lactose is rapidly attacked by Strep. lactis and Lactobacillus species. This lactic acid accumulation and lowered pH cause the milk proteins to coagulate into a solid mass called curd.
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What does curdling do?
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It causes the separation of a watery liquid called whey, on the surface.
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How is curd produced?
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It is produced by microbial action or by an enzyme, rennin(casein coagulase), which is isolated from the stomach of unweaned calves.
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What is an amplified culture regarding cheese production?
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Cheese production uses only freeze dried samples of pure cultures. These are first inoculated into a small quantity of pasteurized milk to form an active starter culture. This amplified culture is inoculated into a large vat of milk, where rapid curd development takes place.
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In the above procedure, what is the advantage of rapid growth?
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This is desired because it promotes the overgrowth of the desired inoculum and prevents activities of undesirable contaminants. Rennin is added to increase the rate of curd formation.
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After separation from whey, the curd is rendered to produce one of the 20 major types of soft, semisoft or hard cheese. TRUE/FALSE
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TRUE. The composition of cheese is varied by adjusting water, fat acid, and salt content.
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Semisoft varieties of cheese such as roquefort, bleu, or Gorgonzola are infused and aged with a strain of Penicillium roqueforti mold. TRUE/FALSE
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TRUE.
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How is yogurt formed?
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It is formed by the fermentation of milk by Lactobacillus bulgaricus and Streptococcus thermophilus. These organisms produce organic acids and other flavor componenets and can grow in such numbers that a gram of yogurt regularly contains 100 million bacteria.
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What is Lactobacillus acidophilus?
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Live cultures of Lactobacillus acidophilus are an important additive to acidophilus milk, which is said to benefit digestion and maintain normal flora.
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What is single cell protein(SCP)?
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This material is produced from waste materials such as molasses from sugar refining, petroleum by products and agricultural wastes.
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In England, an animal feed called pruteen is produced by mass culture of the bacterium Methylophilus methylotrophus. TRUE/FALSE
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TRUE. Mycoprotein, a product made from the fungus Fusarium graminearum, is also sold there.
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What is Spirulina?
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This microbe is harvested from the surface of lakes and ponds, where it grows in great mats. It has become a viable alternative to green plants as a primary nutrient source. It can be eaten in its natural form or added to foods and beverages.
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What is the most common sources of food poisoning?
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Campylobacter
Salmonella Shigells Clostridium Staph. aureus Giardia, Cryptosporidium, Toxoplasma Norwalk and Hepatitis A virus. |
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What are typical temperatures regarding food preservation?
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It depends on the type of food. It can range from 60C to 121C with exposure times ranging from 20 min to 115 min. Food is usually processed at a thermal death point. This will destroy the main spoilage organisms and pathogens but will not alter the nutrient value or flavor.
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List some food examples of pasteurization?
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Tomato juice must be heated to 121C and 132C for 20 min to destroy the agent Bacillus coagulans.
Green beans are heated to 121C for 20min to destroy Cl. botulinum. |
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Vibrio parahemalyticus can survive in frozen shellfish for months. TRUE/FALSE
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TRUE.
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regarding food radiation, gamma rays are more dangerous because they originate from a radioactive source such as Cobalt-60. TRUE/FALSE
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TRUE.
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