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processing of the intestines (intestinal raw material) of farm animals slaughtered for meat to obtain intestinal products (finished products). Intestinal raw material also includes the esophagi and urinary bladders of cattle and swine, which are structurally similar to the intestines. The raw material obtained from a single animal constitutes the intestinal complex. Finished intestinal products are used mainly as casings for sausages. Some 55 percent of the sausage casings are made from animal intestines; the rest of the casings are made from polymeric materials. Nonstandard finished products are used to manufacture cord and sutures. Surgical thread (catgut) and strings for musical instruments and tennis rackets are made from finished sheep products. Processed bladders are also used in the dry goods industry, and serous membranes from the cecum are used in the perfume industry to seal bottles.The use of animal intestines to make thread for sewing footwear and fur clothing and to manufacture strings for musical instruments has been known from very ancient times. The development of the processing of animal intestines is related to the appearance of sausage products. In Russia, the industry dates back to the 16th century. In the 19th century, the Uglich and Moscow sausage-makers also processed intestines. It was a cottage craft in prerevolutionary Russia and was carried on under such unsanitary conditions that even with the low health standards prevailing at that time it was prohibited in slaughterhouses. With the introduction of automation and modern methods, shops for processing intestines were set up in the main work buildings of meat-packing plants. Intestines are also handled in intestinal processing workshops, which receive the raw material from small slaughterhouses that do not themselves process intestines.
The mucous membrane is the weakest of the four layers that make up the intestines, and it is removed when processing almost all kinds of raw material. The submucous layer is the strongest and it is always left intact. The muscular and serous layers are removed or left, depending on how tough they are (which is determined by the section of the intestine) and the purpose of the finished product. The processing of animal intestines includes the following principal operations: separation of the intestinal complex into parts, removal of the intestinal contents and thorough washing of the intestines, fat extraction (skimming), and removal of the mucous membrane (stripping) and other superfluous layers. The mechanized assembly lines used in the processing of animal intestines ensure high output per man-hour and maintenance of hygienic conditions. The processed intestines are cooled with water, graded according to quality and size (diameter, length), tied in bundles, and preserved with table salt or by curing. Slaughterhouses that do not process animal intestines preserve by corning incompletely processed, cleaned, and washed intestines after obtaining the raw material. The final stage of processing takes place in special intestinal processing shops. Salted intestinal finished products are packed in wooden barrels, and dry intestinal products are packed in wooden boxes or barrels for dry matter. Salted intestinal finished products can be stored in refrigerated warehouses at 0°-10°C for one or two years, and dry intestinal products can be kept in dry storage areas at a relative humidity no higher than 65 percent for up to a year.
Techniques and hygiene practices in slaughtering and meat handling
Slaughtering equipment, particularly for smaller-scale operations, need not be elaborate and expensive. The amount of equipment will depend on the slaughtering procedures employed. If possible, all equipment should be made of stainless steel or plastic, be rust resistant and easily cleaned and sanitized. Equipment which does not get in contact with the meat (e.g. overhead rails, working platforms, knocking pen) is usually made of galvanized steel.
Basic equipment needed for the slaughtering operation:
stunning gun, electrical head tongs or simple stunning equipment for direct blow
sticking – 15 cm sharpened on both sides
skinning – 15 cm curved
a sharpening steel
oil or water sharpening stone
scabbard and belt for holding knives
meat saw – hand or electric and cleaver
block and tackle or chain hoist strong enough to hold the weight of the animal to be slaughtered
pritch, chocks or skinning rack (dressing cradle)
a strong beam, tripod or track 2.4 to 3.4 m from floor
spreader – gambrel or metal pipe
scalding barrel or tank
pot, barrel or system for boiling water
solid scraping table or platform
thermometer registering up to 70°C
hog or hay hook
torch or flame for singeing
The last seven items indicate additional equipment required when hogs are scalded and scraped rather than skinned.
Useful additional equipment:
bleeding hooks (for vertical bleeding)
wash trough (tripe) Sanitation of hands and tools:
Means should be available to clean thoroughly all equipment coming into contact with carcasses or meat. Implement sterilizers are stainless-steel boxes holding hot (82°C) water, shaped to suit particular equipmentknives, cleavers, saws, etc. (Fig. 2). Knife sterilizers should be placed in positions where every operator who uses a knife has immediate access. Handles as well as blades must be sterilized. Each operator should have at least two knives etc., one to use while the other sterilizes (Figs 10 and 11).
Failure to sterilize all knives and equipment regularly will result in carcass contamination. Bacteria will be transferred from the hide to the carcass and from carcass to carcass.
Slaughter and dressing of animals, and handling and inspection of meat, presents many opportunities for cross-contamination. Personal hygiene practices should prevent undue general contamination, and prevent cross-contamination with human pathogens that may cause food-borne disease. The guidelines presented in this section are supplemental to the objectives and guidelines in Section VII of the General Principles of Food Hygiene.
Persons moving from rooms or areas containing raw meat to rooms or areas used for meat preparations and manufactured meat (especially when these products are cooked) should thoroughly wash, change and/or sanitise their protective clothing as appropriate, and otherwise limit the possibility of cross-contamination to the lowest level practicable.
Persons who come into direct or indirect contact with edible parts of animals or meat in the course of their work should maintain appropriate personal cleanliness and behaviour, and should not be clinically affected by communicable agents likely to be transmitted by meat.
Persons who come into direct or indirect contact with edible parts of animals or meat should:
maintain an appropriate standard of personal cleanliness;
wear protective clothing appropriate to the circumstances, and ensure that non-disposable
protective clothing is cleaned before and during work;
if wearing gloves during the slaughter and dressing of animals and the handling of meat, ensure
that they are of an approved type for the particular activity, e.g. chain-mail stainless steel,
synthetic fabric, latex, and they are used according to specifications, e.g. washing of hands before
use, changing or sanitising gloves when contaminated;
immediately wash and sanitise hands and protective clothing when there has been contact with
abnormal animal parts that are likely to harbour food-borne pathogens;
cover cuts and wounds with waterproof dressings; and
store protective clothing and personal effects in locations that are separate from areas where meat
may be present