By goGreen | July 31, 2012
Deterioration of fruits and vegetables during storage depends largely on temperature. One way to slow down this change and so increase the length of time fruits and vegetables can be stored, is by lowering the temperature to an appropriate level. It must be remembered that if the temperature is too low the produce will be damaged and also that as s
oon as the produce leaves the cold store, deterioration starts again and often at a faster rate.
It is essential that fruits and vegetables are not damaged during harvest and that they are kept clean. Damaged and bruised produce have much shorter storage lives and very poor appearance after storage. Dirty produce can introduce pests and moulds into the store. The produce should be harvested carefully using a sharp stainless steel knife. The fruits and vegetables should not be placed on the ground where they could pick up dirt. Either a clean harvesting basket or clean mats should be used. It is essential that the fruits and vegetables are harvested at the correct harvesting time.
It is important that the produce does not get dirty or damaged during handling. Careful handling should be the rule. The best option is for the produce to be prepared for storage in the field and placed carefully in the storage containers used in the cold store. This considerably reduces the amount of handling and will keep damage to a minimum. It is essential that the produce is handled and placed in the store as quickly as possible as delays between harvesting and cooling can substantially reduce storage life.
If the produce is dirty it should be cleaned before storage. The water used has to be kept clean or fungus spores will be spread throughout the produce. Some fruit and vegetables need their outer leaves removed before storage. However, usually it is better to leave the leaves on during storage to reduce moisture loss, and then remove them before sale.
Preliminary cooling (Precooling)
Dipping the produce in cool water to remove field heat can reduce the energy requirements of the store. However, this can spread fungus spores throughout the produce. A suitable alternative is to pick the produce either early in the morning when it is cool or late in the evening and leave it overnight to cool down.
All fruits and vegetables have a 'critical temperature' below which undesirable and irreversible reactions or 'chill damage' takes place. Carrots for example blacken and become soft, and the cell structure of potatoes is destroyed. The storage temperature always has to be above this critical temperature. One has to be careful that even though the thermostat is set at a temperature above the critical temperature, the thermostatic oscillation in temperature does not result in storage temperature falling below the critical temperature. Even 0.5C below the critical temperature can result in chill damage. Table 1 gives the critical temperatures for various fruits and vegetables.
It can be seen from the table that there are basically three groups of fruit and vegetables: those stored at 0 – 4C; those stored at 4-8C and those that require a storage temperature above 8C. It is often more convenient to concentrate on one of these groups.
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By goGreen | July 29, 2012
Fish can be grown in open ponds
or in cages in ponds. Shellfish, on the other hand, often do better in what is called suspensionculture. These three methods are described below.
POND FISH CULTURE
Types of Pond Culture
There are four general types of pond fish cultures: mixed age groups, temporary age group mixing, separated age groups, and controlled reproduction.
The Mixed Age Groups Method. This method produces all sizes of fish in great quantity. The level of production is maintained by catching some fish while the fish are growing. This may be done with a hook and line or a limited number of traps. At the end of the growth period, the pond is drained and all fish are harvested. Some are selected for restocking the pond when it is refilled. This method provides a high production rate if the fish are well-fed. Fish from a different source should be put if the pond periodically to improve the fish quality.
The Temporary Age Group Mixing. This culture produces a large portion of equal-sized fish. The pond in stocked with young fish of approximately the same size, which are fed and allowed to grow and reproduce once. When the largest of the fish spawned in the pond are large enough to use for restocking, the pond is drained and the fish harvested. All adults are sold or used for food; the smaller fish are used for restocking. In this method, the weight per fish is usually small. A mixed size fishery usually evolves from temporary size mixing.
Separated Age Groups Method. In this method, two ponds and heavy feeding are used to produce table or market-size fish as rapidly as possible. Adults of a single species are introduced into a reproduction pond. When the young spawned in the reproduction pond are large enough to survive in a larger growing pond, they are transferred to the larger pond.
The “Natural” Predation Method. This method attempts to balance the fish's growth and reproduction through the introduction of a predator. The results of this method are uncertain, since over-predation will reduce or even eliminate the population, leading to too many fish that are too small (dwarfing).
Controlled Reproduction Methods. These methods control the sizes and numbers of fish in the growth ponds by controlling reproduction within a laboratory. Fish stock in the ponds do not reproduce because conditions in the pond are not favorable for the species used or because something is done in the laboratory to prevent fertility. One method that has been used with some success if separation of fish by sex. Males and females are simply placed in separate ponds. However, this is a very difficult method to use, because a small number of males in the female pond (or vice-versa) will cause reproduction in the female pond (and in the male pond to a lesser extent).
Other methods include production of sterile hybrids, operating on fish to sexually denature them; or treating the fish to reduce fertility.
Construction and Operation of Fish Ponds
Once pond cultivation has been decided on, the technical considerations must be addressed. A suitable location with an adequate water supply must be chosen. The soil must be able to contain the water in the pond. The water quality must be adequate for the species, and the quantity must fill the pond in less than one month and replace losses due to seepage and evaporation.
Water Supply. There are several sources of water for pond culture, including rainfall, surface water, springs, and wells. Surface water often contains unwanted fish, pollution, parasites, and disease, and is the least desirable water source. It is often necessary to aerate to remove undesirable gazes and raise the oxygen level. Springs may also contain unwanted fish and can dry up at the time water is most needed. Rainfall may be even more undependable and low in nutrients. But it will generally be free of pollutants and high in oxygen.
Well water in usually the highest quality (especially when it comes from covered wells). It does not contain unwanted fish or suspended material, and is protected from flood water. But it also may need aeration to remove undesirable gases and raise the oxygen level. If the well's water source is of uncertain quantity or quality, test wells should be constructed first.
The minimum pond water depth depends on the air temperature, seepage rates, and the dependability of the water supply. In an area dependent on seasonal rains, the water should be at least 3m(10 feet) deep over at least 25 percent of the pond. In warm areas with low seepage or sufficient water supply, the minimum depth may be as little as 1m (3 feet). If the pond will be ice covered for one month or more, the pond will have to be at least 6m (20 feet) depth to prevent winter-kill.
Woods may grow in shallow water. Since this may be beneficial, removal will depend on whether the benefits outweigh the problems associated with the additional use of nutrients, loss of pond volume, and potential oxygen use when the plants decay. Shallow areas with weeds are favorite brooding areas for mosquitoes. It is recommended that the pond be not less than 12 (3 feet) deep to minimize weed and mosquito growth, or herbivorous fish, such as grass carp, should be among the species stacked in the pond.
Topics: Aquaculture | Comments Off
By goGreen | July 29, 2012
Aquaculture is the production of protein-rich foods through the controlled cultivation and harvest of aquatic plants and animals. Using inexpensive equipment and simple techniques, aquaculture can supply more protein than normally produced through conventional agriculture such as dairy, poultry, and cattle farming; and traditional fishing.
Aquaculture is not new. More than 2,500 years ago the sticky eggs of some fish were collected on mats and bundles of reeds or wood attached to posts in streams. Oyster and clam eggs were also collected and transferred to other waters to hatch. This was the first form of aquaculture.
In the 11th and 12th centuries, pond culture developed. Carp were moved through a series of ponds where they reared young fish and grew to harvest size. Later, other fish were cultured in a similar manner. Today, several types of fish and shellfish are grown in high density aquaculture operations throughout the world.
The techniques of animal husbandry improve the chances of survival of the plants and animals being raised and speed up their growth so that the food yield is quick and large. Almost any type of aquatic organism can be raised from its youth to a healthy, marketable adult. However, this paper in restricted to fish and shellfish culture. The reader is presented with only general considerations and approaches to aquaculture, since it requires specialization to address each possible cultural species.
Advantages and Disadvantages of Aquaculture
Systematic aquaculture operations have a number of advantages over fishing for the production of protein foods. Some of these are:
- Economics (employment, new industry and support services, and increased foreign and domestic ex change);
- No need for expensive fishing craft and gear;
- Low operating and maintenance costs;
- Low capital investment (unless Ponds must be constructed;
- Reasonably predictable yields;
- Less time lost due to bad weather or breakdowns;
- Fewer equipment malfunctions and injuries;
- Reduced health risks to consumers.
Aquaculture operations do have drawbacks, however. These include:
- Water is necessary, in predictable quantity and quality;
- Large land area on which to construct ponds or access to large shallow area of water is required;
- Knowledge of culture conditions may not be generally available.
Types of Aquaculture
There are five major types of aquaculture:
1. Transplantation: The movement of a species to a suitable location. This method in also used to introduce species into new environments.
2. Hatchery and Stocking: The spawning, hatching, and rearing of a cultural species that will be transplanted to suitable or desirable areas. This method is used to supplement or replace the natural stock, or for transplantation.
3. Enbayment Culture: The use of enclosures, such as ponds, cages, baskets, and strings, for aqua culture in natural waters.
4. Ponds with Supplemental Feed and Fertilizer: Aquaculture in natural or artificial ponds with food and fertilizer provided to maintain algae and species at desirable levels. In some systems, animal manures are used to provide fertilizer and some food.
5. Ponds without Supplemental Feed and Fertilizer: Aquaculture in natural or artificial ponds with the cultured species subsisting an natural available food in the pond water. This requires a high rate of exchange of water for high growth rates.
As can be seen, the basic theory of aquaculture is to obtain small animals and provide them with an environment that allows for their rapid, healthy growth. A desirable-sized fish can be harvested in a short period of time.
The most commonly cultivated species of fish are carp and tilapia. Shellfish such as oysters and mussels, which are low on the food chain, are also farmed extensively. While culture techniques must be adapted to the needs of specific species and to local needs and conditions, some general rules apply:
1. The species must be Suitable for cultivation under the proposed conditions.
2. The program must develop the best method of cultivating the identified species from physiological, geographical, and market points of view.
3. Adequate support must be available. This includes changing and aerating the water, feeding the fish, maintaining equipment, marketing, and so on. Experimentationis often necessary to improve yields substantially.
4. Predators must be controlled.
5. Cannibalism must be controlled.
6. The species life cycle must be understood, and good, inexpensive feed must be available.
A dense population of animals demands abundant food and oxygen and a means of removing metabolic wastes. There is a limit to the size of the biological community that can be supported before growth is limited by competition for food, oxygen, and space. The high density of cultured animals makes them susceptible to disease and predation. To prevent juveniles from being attacked by these diseases, drained ponds must be thoroughly dried to destroy parasites and disease-causing organisms. The water and stocking animals should be free of parasites and disease-causing organisms. Feed and feed supplements should not introduce parasites or disease-causing organisms.
On the positive side, the fertile fish and shellfish wastes can be used in the production of leaf crops requiring nitrogen. Shellfish wastes are best used on fruit trees.
OVERALL OPERATION AND MAINTENANCE
Aquaculture systems can be operated and maintained in three ways:
1. Communal: This is subsistence cultivation that is some times publicly funded. The conditions are often mediocre,and production is poor because duties are attended randomly.
2. Family: This can range from subsistence cultivation to a very sophisticated operation, depending on the skill and energy of the owners. Under the worst of conditions, it can be more variable than communal; at its best, it can exceed the standards of a dedicated system. The key to a successful operation is the family's commitment to putting forth the effort necessary to produce a quality product.
3. Dedicated: This operation is designed to produce food for market, and is usually well-regulated with high yields.
Each of these types of operation can be run as extensive or intensive culture.
Extensive Culture provides little or no control over the environment. Placing shellfish on a site and allowing them to grow on their own, or trapping fish and invertebrates in special enclosures and holding them until they reach market size, are examples of extensive culture. In extensive culture, the fish depend uponthe natural food supply in the water. Only 20 to 50 percent of the stocked animals survive in this uncontrolled environment.
Intensive Culture on the other hand provides full control, over the environment. An indoor culture of shellfish, in which temperature, salinity (salt/water ratio), flow rate, feed type, amount of feed, and light are fully controlled, is an example of intensive culture.
No matter which type of operation or which method of culture is selected, sufficient food and oxygen must be provided. Oxygen levels of 4 to 5 milligrams per liter (parts per million) are satisfactory. Water can be aerated by spraying it out at least 0.6m (2 feet) in droplet form. Food requirements are discussed in a later section.
There is one other general consideration in aquaculture that is extremely important: The size of the animals. The animals stocked in the aquaculture system must be large enough to grow to market size in the desired time. Some preliminary experimentation is needed to determine the minimum desirable size. Only healthy animals should be chosen for stocking the aquaculture system.
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Topics: Agri-Business | Comments Off
By goGreen | July 28, 2012
The common potato (Solanum tuberosum, Solanaceae) is a member of another large and important plant family, Solanaceae, which includes, among many others, eggplant and tomato. Th
e genus Solanum includes more than 2,000 species.
The potato was first seen by Europeans in 1537 when the Spanish landed in what is now called Colombia, and was brought back to Europe by 1570. It was cultivated throughout the continent before 1600, and in Ireland by 1663. The cultivated potato is said to have been first introduced into North America in 1621.
Potatoes are the leading starchy root crop of the subtropical countries, and one of the eight leading staple food crops of the world. Annual production of potatoes is approximately twice that of all other edible root crops combined. However, because of its limited climatic adaptability, less than 10 percent of production occurs in developing countries. The International Potato Center (CIP) in Peru is developing new varieties of this nutritious root crop, which perform well under a variety of soil and climatic conditions.
Among the root crops, the potato is known for its high protein content. It is almost equal to rice on a dry weight basis, and with a protein quality approaching that of beef. With its high yields and short maturation periods, the potato outranks all major world food crops in protein production per unit of time. The food value of the potato varies depending on the variety, growth, environmental conditions, storage, and handling. Its composition consists of 70 to 80 percent water, 8 to 28 percent starch, and 1 to 4 percent protein. It also contains vitamins such as riboflavin, ascorbic acid, and trace elements. It is an important source of high-quality nutrients for people in the tropical highlands. The potato has been a continuous object of research and investigation all over the world, with special focus of interest in the International Potato Center (CIP) in Peru. The Center is attempting to increase the tolerance of the crop to high temperatures, and once it is accomplished, then it is likely that larger areas of West Africa will be open to cultivation.
Potatoes are grown as a single crop or in combination with sorghum, millet, maize, cowpeas, groundnuts, sweet potatoes, and other vegetables. Propagation is done by tuber, either whole or cut. Whole tubers are less liable to rot in the soil. Planting material should be free from diseases, pests, and damage. Certified potato “seeds,” free from virus, should be used when possible. Potatoes may be planted by hand or mechanically, and the crop is usually planted on ridges at a depth of 5 to 15 centimeters.
Most potato varieties have very specific temperature requirements, thereby limiting the adaptability of this crop in tropical regions. Tuber formation is retarded when the soil temperature rises above 20 [degrees] C; above 29 [degrees] C, little if any, tuberization takes place. Although young potato plants are very susceptible to hard frosts, most varieties will tolerate light frosts.
Potatoes require a continuous supply of moisture. Evenly distributed rainfall is considered essential, and drought, even for short periods, can have serious effects on yields and quality of the crops. Well-drained peat soils are particularly suited; however, potatoes could grow on most soils if drainage is adequate. A deep, well-drained loam, or sandy loam, with a pH of 5 to 5.6 is considered to be the best. Potatoes respond well to manures and chemical fertilizers, and good yields can be obtained only with adequate fertility. Fertilizer requirements vary greatly depending on the variety and growing conditions.
Potatoes do not compete well with weeds, and timely, efficient weeding, by pulling or tillage, is essential. In temperate zones, the crop is often repeatedly hoed, up to five times during the growing season. Normally, the crop is ready for harvest in three to four months. Harvesting should be done on a dry day, when the tubers are mature. The crop can be harvested by hand or mechanically. If it is harvested mechanically, a wide range of equipment can be used, including diggers, spinners, and ploughs. Harvested tubers should be stored temporarily in a shaded, dry, and well-ventilated place for 7 to 10 days to allow the skins to harden before the potatoes are prepared for market or storage. Potato yields vary with variety, length of growing season, climate, and the type of soil. With efficient farming methods in temperate climates, yields well in excess of 25 metric tons per hectare are quite common. Yields are lower in the tropics, averaging about 14 to 15 metric tons per hectare.
Potatoes can be eaten boiled, roasted, baked, fried, or mashed. They can be made into fried chips or crisps, dehydrated and flaked, or made into flour. Potatoes can be pulped and fermented to produce alcohol. Potato tubers make an excellent livestock feed and can be fed fresh or dried and used in the form of a meal.
Diseases and Pests
Potato crops are subject to a number of diseases, some of which are of great economic importance in both developed and developing countries. Brown rot, or bacterial wilt, is the most serious potato disease in West Africa. The disease is carried by seed tubers. Other bacterial diseases include soft rot, ring rot, and late blight. Several other diseases are also of considerable importance. Among these are virus diseases that can cause crop losses. Virus-free planting stock is essential since there are no effective treatments for these diseases. Finally, a number of pests, particulary aphids and nematodes, have been found to cause economic losses. These pests not only harm the crop, but also spread virus diseases such as leaf roll and mosaic.
Source: Understanding the Production of the Major Tropical/ Sub-Tropical Root Crops
By Dr. Nail H. Ozerol
By goGreen | July 28, 2012
The Mushroom Bed Foundation The foundation for bedding material can be soil, concrete, or a wooden bench. A soil foundation is made by raising the soil i
n the same manner used to build a garden plot to a height of about 12 cm above ground level. It is surrounded by a canal 30 cm wide and 15 cm deep. The earth excavated from the canal is used to elevate the foundation The width of the foundation should be 45 cm, and the length 1 m or more. Sandy soil will not make a strong enough foundation, but this can be remedied by cementing the sides or by constructing a wooden bench 30 cm high with the rest of the dimensions the same.
Rice Straw as Bedding Material
Thoroughly dried, long rice straw is preferable. Properly prepared straw produces a better yield of mushrooms compared to the yield when care is not taken to provide a strong base.
The straws are bundled to a size of about 8 cm in diameter, tied at the middle with abaca twine or any good substitute, cut to a uniform length of 45 cm and soaked in water for three hours. The soaked straw bundles are laid crosswise side by side on top of the bed foundation until the whole length of it is covered. All the butt ends are placed on one side in a layer, alternating between layers. If the butt ends of the first layer are on the left side, the butt ends of the second layer must be on the right side. This manner of arrangement is continued until four to six layers are made. About 240 bundles are needed for a six-layer, 4-metre-long bed. Each layer must be pressed firmly to make the surface level, and should be watered.
Simultaneously with the bed preparation, several crumpled newspapers are soaked in a container with 3 9 of urea per gallon of water. This “fertilized” paper is planted along with the mushroom spawn or seed. The mushroom spawn and soaked paper are first distributed on top of the layer in thumb-sized pieces. The plantings are 5 – 8 cm from the edge of the straw and 5 cm apart. For every six-layer bed 4 m long, three bottles (16 fl. oz.) of spawn are used. One-half bottle of spawn is apportioned to plant one layer. The spawn is buried with the paper 4 cm deep in the layer. The same procedure is repeated on the remaining layers. Any left-over straw is mounded on top to a thickness of about 10 cm at the centre.
The straw bed is protected by an elevated, transparent plastic sheet immediately after the planting. The cover is attached to a bamboo frame to prevent the moisture that accumulates on the plastic from spilling onto the straw.
During the dry season, a four-layer bed is recommended because of lower relatively humidity. Beds of six or more layers are possible in the wet season.
Banana Leaves as Bedding Material
Dried banana leaves, still hanging on the plant, are gathered and cut to a uniform length of 45 cm, bundled to a diameter of 8 cm, and soaked in water for three or four hours.
The leaf bed is made in a manner much the same as that used for straw; i.e., the bundles are laid side by side crosswise on the bed foundation, watered, pressed, and planted. Four or sixlayer beds are constructed, depending on the season. The leaf bed also requires the elevated plastic sheet on a bamboo frame immediately after planting.
Topics: Agri-Business | Comments Off
By goGreen | July 27, 2012
As a result of the high cost of meat, people are constantly looking for a cheaper source of protein. Eggs provide a valuable yet affordable source of high quality protein and vitamins required for normal growth, especially for children.
This guide will show you how to build, manage and maintain your own affordable household egg production unit on a small scale. Later on you can increase the size of your unit in order to sell eggs in your community, if the demand for eggs is big enough.
The information given is based on poultry production in the warmer to hot areas of South Africa.
Why Keep Hens?
You can provide eggs for your family by keeping 9 to 12 hens. Each hen will lay up to 6 eggs per week. In this way you can even start your own small business. If you have 9 hens, they will lay 8 to 9 eggs per day. You will need to sell 4 eggs per day to pay for the feed of the hens. The remaining eggs can be used for household consumption. Eggs provide a valuable yet affordable source of high quality protein and vitamins required for normal growth, especially for children, when meat is too expensive or is unavailable. If there is a demand for eggs in your area, you could expand and sell more of the eggs.
It is best to keep the hens in a cage. This means that:
• the hens can be kept in a small space
• the hens are kept in a cleaner environment
• the eggs are not broken easily
• the eggs stay clean
• the eggs can be collected easily
• the hens get fewer diseases
• there is less chance of hens being stolen
• they need very little care
• it is very easy to keep the cage clean as the manure falls through the mesh floor
• you can easily see when drinking water is finished
• feed is not wasted easily
• it makes good record keeping possible.
You can buy the cage or make your own. It is, however, cheaper to make the cage yourself. The cage should not stand on the ground to ensure that the manure falls through. Put the cage on poles, bricks or fasten it to the wall of a house, hut, shed or hang it from ropes tied to poles. The cage should be protected from overhead sun and rain by an overhang or roof (eg thatch).
In hot climates keep 9 hens in a cage—3 in each compartment. (In this way there is enough space for limited movement, and they can all get to the feed trough at once) In cold climates, 4 hens can be kept in 1 compartment (total of 12), but then their movement is very limited.
You can buy day-old chicks and rear them, but this is expensive and often the chicks die if they do not receive good care. It is better to buy young hens, called point-of-lay pullets (18-19 weeks old) which are ready to start laying eggs. The hens you buy must be of very good quality and be fully vaccinated against all known poultry diseases.
The best layer breeds to buy are: Amberlink or Hy-line laying hens—these hens will start laying within 2 weeks after being bought (20-21 weeks of age). First (pullet) eggs are small, but gradually become larger after about 2 months.The number of eggs laid also peaks halfway through the year and then starts dropping.The hens should be kept for 1 year and then sold as cull hens. If the feed is very cheap, the hens can be kept up to 2 years. If you keep the hens for longer than 1 year, they will start laying fewer eggs until they stop altogether. They will, however, eat the same amount of food, so profits become less and the enterprise eventually uneconomical.
Before selling the hens for slaughter, you must order new pullets. Do this at least 4 months ahead of time. You can only start selling your old hens once the new hens are in production, especially if you have standing orders with clients and do not want to disappoint them. The money made from the old hens will pay for the new hens.
By goGreen | July 27, 2012
Source: Intermediate Technology Development Group
Ginger is obtained from
win back your ex>
the rhizomes of the plant Zin giber officinale Roso. It originated in South East Asia and is valued for the dried ginger spice and preserved, crystallized ginger.
Before processing ginger it is recommended that a market survey is carried out. This will include information on the availability of raw material, availability of processing materials and equipment, access to markets and demand for the different ginger products. This information should indicate whether your business is likely to succeed.
Ginger is usually available in three different forms;
fresh (green) ginger
preserved ginger in brine or syrup dried ginger spice
Fresh is usually only eaten in the area where it is produced although it is possible to transport fresh roots overseas. Both mature and immature rhizomes are consumed as a fresh vegetable.
Preserved ginger is only made from the immature rhizomes. Most preserved ginger is exported. Hong Kong, China and Australia are the major producers of preserved ginger and dominate the world market.
Making preserved ginger is not simple, it requires a lot of care and attention to quality, only the youngest, most tender stems of ginger should be used. It is difficult to compete with the well established Chinese and Australian producers. This technical brief will only describe the production of dried ginger.
Dried ginger spice is produced from the mature rhizome. As the rhizome matures the flavor and aroma become much stronger. Dried ginger is exported, usually in large pieces which are then ground into a spice in the country where it is used. Dried ginger can be ground and used directly as a spice and also for the extraction of ginger oil and ginger oleoresin.
There are two important factors to consider when selecting ginger rhizomes for processing;
a. the stage of maturity at harvest
b. native properties of the type grown
By goGreen | July 26, 2012
3 mugs root crop flour
2 teaspoons baking powder
2 mugs mashed sweet potato
6 level tablespoons sugar
1 tablespoon margarine
For firm ingredients you might want to use the INPhO weight calculator. For liquid ingredients the volume table could be useful.
By goGreen | July 25, 2012
While it is obviously very nice to have a brand new building to house any food production unit, this is of course not always possible. The following notes are therefore intended as a guide for those either starting-up from the beginning or converting an existing structure.
Walls and general internal finish
All internal walls should be, at least, smooth plastered in production areas to allow for thorough cleaning. Ledges and rough finishes must be avoided as dust will accumulate and they are very difficult to clean. If money permits, glazed tiling on the walls to a level of some 4 feet is highly recommended. If this proves impossible, selected areas should be ceramic tiled (for example behind sinks or where machinery will cause considerable product splashing).
Attention should be given to preventing the access of birds, rodents and flying insects through gaps in the roof structure and in particular where the roof joins the wall. In tropical climates, overhanging roofs that keep the direct sunlight from the building walls will make life for the workers more comfortable.
Most food processing operations involve wet processes so it is obviously very important to make sure that the floor is made of good quality concrete which slopes to a central drainage channel. This means that at the end of the day the whole floor area can be hosed down and drained naturally to a central point. The drainage channel should be fitted with a heavy iron grating that can be easily removed for internal cleaning of the drain. The point where the drain exits from the building may require special attention, as an open drain at this point provides a corridor for rats and mice to enter the structure. Wire mesh should be fixed over the end of any drain opening of this type. The joint between the sloped production floor and the walls is another area that needs attention. A right angle join provides an excellent point for dirt to lodge and the cement floor screed should therefore be curved to meet the wall surface.
Topics: Miscellaneous | Comments Off
By goGreen | July 25, 2012
Butter can be made from fresh or fermented milk. If fresh milk is used, it must first be separated into skim milk and cream. The cream is churned and the final product is known as sweet butter.
The milk used to make lactic butter does not require separation into skim and cream. Instead milk is fermented to form yogurt, and lactic butter is produced directly from churning of the yogurt.
Sweet cream butter
Raw milk is first separated into skim and cream in a centrifugal separator (electrically or manually powered). Milk with a high fat content gives a higher butter yield.
The fat content in the cream is determined using a Gerbera cream butyrometer. The cream should then be standardized to approximately 40% fat content using the separated skim milk. Standardization of cream to the correct fat content is important, because it affects the churning efficiency and thus butter yield.
Standardized cream is then pasteurized at 72C for 15 seconds or 63C for 30 minutes. These are minimum pasteurization requirements, and for improved keeping quality of the butter, especially where the process is not automated and thus temperature holding times are only approximate, it is advisable to exceed the minimum heat treatment, e.g. 75C for one minute.
The cream should be continually stirred during heating to ensure even heat distribution, and timing started when it reaches the correct temperature.
Pasteurized cream is then chilled below 4C for several hours (or overnight). This 'ages' the cream and improves its churning efficiency and butter yield.
The next day, aged cream is churned either in a butter churn or a small mixer, (eg Kenwood Chef). It is important to keep the temperature as low as possible during churning. During churning, cream viscosity increases, and finally the cream 'breaks'. This is a clear separation of cream into butter grains and buttermilk. Churning should be continued until butter grains adhere together into one lump.
The buttermilk is drained off and clean, chilled water added to the butter. Slow churning cleans the butter from residual buttermilk, which reduces the keeping quality of the butter if allowed to remain. The water is drained off, and 1-2% salt (of butter weight) is added to the butter during continued slow churning, to achieve even salt distribution.
The butter is then packaged into grease-proof paper, and stored below 4C.« Previous Entries