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Even pasteurization without quality control can be effective, though this is generally not permitted for human consumption; a study of farms feeding calves on pasteurised waste milk using a mixture of pasteurization technologies (none of which were routinely monitored for performance) found the resulting pasteurized milk to meet safety requirements at least 92% of the time. | Even pasteurization without quality control can be effective, though this is generally not permitted for human consumption; a study of farms feeding calves on pasteurised waste milk using a mixture of pasteurization technologies (none of which were routinely monitored for performance) found the resulting pasteurized milk to meet safety requirements at least 92% of the time. | ||
Revision as of 06:43, 11 March 2021
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3a
3b
3c
3d
3e
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6
Hand Milking
Adventist Youth Honors Answer Book/Milk a cow
Machine Milking
Milking machines are used to extract milk from cows when the herd is larger than about 4 cows. The milking unit is the portion of a milking machine for removing milk from an udder. It is made up of a claw, four teatcups, long milk tube, long pulsator tube, and pulsator. The claw is a manifold which connects the short pulse tubes and short milk tubes from the teatcups to the long pulse tubes and long milk tubes. Claws are commonly made of stainless steel or plastic. Teatcups are composed of a rigid outer shell (stainless steel or plastic), which holds a soft inner liner or inflation. Transparent sections in the shell may allow viewing of liner collapse and milk flow. The annular space between the shell and liner is called the pulsation chamber.
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The descriptions of these parts can be found in requirement 6 above.
- Claw
- Teatcups
- Short milk tubes
- Long milk tube
- Short pulse tubes
- Long pulsator tube
- Pulsator
- Collection bucket
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Mastitis is the inflammation of the mammary gland. It is usually caused by a bacterial infection from Staphylococcus, Streptococcus, E. coli, or Mycoplasma. It can have many causes, including by poor milking practices, poorly fitting teatcups, faulty milking equipment, and freezing. It can be spread to other cows when bedding is shared between an afflicted cow and a healthy cow. It can be prevented by vaccination.
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Mastitis
Mastitis is an inflammation of the mammary glands. It has been covered in the previous requirement.
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10a
10b
10c
10d
10e
10f
10g
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Even pasteurization without quality control can be effective, though this is generally not permitted for human consumption; a study of farms feeding calves on pasteurised waste milk using a mixture of pasteurization technologies (none of which were routinely monitored for performance) found the resulting pasteurized milk to meet safety requirements at least 92% of the time.
An effect of the heating of pasteurization is that some vitamin, mineral, and beneficial (or probiotic) bacteria is lost. Soluble calcium and phosphorus decrease by 5%, thiamin and vitamin B12 by 10%, and vitamin C by 20%. However, these losses are not significant nutritionally.
Verification Direct microbiological techniques are the ultimate measurement of pathogen contamination but these are costly and time consuming (24-48 hours), which means that products are able to spoil by the time pasteurisation is verified.
As a result of the unsuitability of microbiological techniques, milk pasteurisation efficacy is typically monitored by checking for the presence of alkaline phosphatase, which is denatured by pasteurisation. B. tuberculosis, the bacterium requiring the highest temperature to be killed of all milk pathogens is killed at similar ranges of temperature and time as those which denature alkaline phosphatase. For this reason, presence of alkaline phosphatase is deemed to be an ideal diagnostic tool for pasteurisation efficacy.
Phosphatase denaturing was originally monitored using a phenol-phosphate substrate. When hydrolysed by the enzyme these compounds liberate phenols, which were then reacted with dibromoquinonechlorimide to give a colour change, which itself was measured by checking absorption at 610 nm (spectrophotometry). Some of the phenols used were inherently coloured (phenolpthalein, nitrophenol) and were simply assayed unreacted. Spectophotometric analysis is satisfactory but is of relatively low accuracy because many natural products are coloured. For this reason, modern systems (since 1990) use fluorometry which is able to detect much lower levels of raw milk contamination.[25]
Care of Dairy Appliances
The milking machine gets the most use and abuse of anything on a dairy farm, yet is sometimes taken for granted. Proper equipment care will increase production and reduce frustration. Some farmers choose to have a dairy service perform regular checks and maintenance on their equipment, while other more mechanically gifted farmers so most work themselves. Most farmers take some middle path. From changing the milk filter every day to annual checkups of the whole system, it is important to follow the recommended service intervals. Even though a component like the teat cup may look fine, when it reaches the end of its service life it is developing microscopic holes that can harbour disease.
Keeping all equipment clean with water and food safe cleaners is very important as well to ensure the safety of the milk.
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This is going to be the hardest part of the honor to arrange if you do not live on a dairy farm.
References
- This article details how cows digest grass to make milk. http://www.dairy.edu.au/discoverdairy/Students/From-Farm-to-Plate/How-Cows-Make-Milk.aspx
- Wikipedia on Cow Feeding http://en.m.wikipedia.org/wiki/Cattle_feeding
- Feeding by age/stage of life. http://www.ilri.org/InfoServ/Webpub/fulldocs/SmHDairy/chap7.html
- http://babcock.wisc.edu/node/150
- detailed explanation of crude protein. http://research.vet.upenn.edu/dairynutrition/ProteininDairyCows/tabid/3715/Default.aspx
