Meat Lecture 7 and Pork Processing

Meat industry by-products

Animal materials recovered in addition to the main carcass meat; used for food, industrial products, feeds, fertilizers, and pharmaceuticals.

Economic importance of by-products

Recovering and selling by-products adds livestock value and can determine packing-plant profitability.

Live weight versus dressed carcass weight

Live weight is the animal before slaughter; dressed carcass weight is the carcass after removal of specified noncarcass parts.

Dressed carcass versus retail cuts

The dressed carcass includes components removed during fabrication; retail cuts are the portions prepared for consumer sale.

Edible versus inedible by-products

Edible by-products enter human food uses; inedible by-products enter uses such as industry, animal feed, fertilizer, or pharmaceuticals.

By-product drop value

The combined economic value of recovered by-products from a slaughter animal.

Value of bleachable beef tallow in the lecture

Highlighted as a major contributor to offal value because of biodiesel demand.

Variety meats

Edible organs and other nontraditional meat items, such as liver, heart, kidneys, tongue, and sweetbreads.

Liver: food-use category

Variety meat; also sold in export markets.

Heart: food-use category

Variety meat.

Kidneys: food-use category

Variety meat.

Spleen or melt: food-use category

Variety meat.

Sweetbreads: food-use category

Variety meat; also sold in export markets.

Tongue: food-use category

Variety meat; also sold in export markets.

Oxtails: food-use category

Variety meat commonly used in soups; demand can be seasonal.

Cheek and head trimmings: food-use category

Ingredients in processed meats and prepared meat dishes.

Beef extract: food-use category

Flavoring for soups and bouillon.

Blood: food-use category

Ingredient in some sausages.

Suckling calf stomach: food-use category

Source of rennet for cheesemaking.

Pork stomach: food-use category

Sausage container or ingredient.

Beef rumen: food-use category

Source of tripe.

Beef reticulum: food-use category

Source of honeycomb tripe.

Bones: edible-product category

Source material for gelatin used in food products.

Edible fats from cattle and sheep

Used in food ingredients such as shortening and confectionery products.

Edible pork fat

Processed into lard.

Small intestines: food-use category

Natural sausage casings.

Large intestines: food-use category

Natural sausage casings; pork large intestines can also be eaten as chitterlings.

Chitterlings

Edible pork large intestines.

Weasand

The esophagus; used as a sausage ingredient.

Pork skins: edible-product categories

Fried pork skins and food gelatin.

Calf skin trimmings: edible-product category

Source material for food gelatin.

Cattle hides: industrial-product categories

Leather, glue, and hair products.

Pork skins: inedible-product category

Tanned skin used for leather goods.

Sheep pelts: recovered materials

Wool, skin, and lanolin.

Lanolin

Wool-derived material used in ointments.

Inedible tallow: use categories

Industrial oils, lubricants, soap, glycerin, and biodiesel.

Hog grease: use category

Industrial oils.

Tankage, cracklings, and stick

Rendering by-products used in livestock and poultry feeds.

Dry bone: industrial-use categories

Glue production, steel hardening, and sugar refining using bone charcoal.

Bone meal: use categories

Animal feed and fertilizer.

Blood albumen: industrial-use categories

Leather preparations and textile sizing.

Cattle feet: industrial-product categories

Neatsfoot stock and oil for lubricants and leather preparations.

Glands: inedible-product categories

Pharmaceuticals and enzyme preparations.

Lungs: inedible food-use category

Pet food.

Skin versus hide

Skin generally refers to lighter animal coverings; hide generally refers to heavier animal coverings.

Slunk skin

Skin from an unborn calf; highlighted in the notes as a luxury material.

Kip skin

A calf-skin classification between smaller calf skins and heavier hides.

Bull hide

A relatively thick hide.

Stag hide classification

Accepted as steer or bull hide depending on its characteristics.

Native hide

An unbranded hide; the most valuable brand category in the handout.

Effect of branding on hide value

Brands damage usable leather and reduce hide value.

Butt brand versus Colorado brand

A butt brand is on the rump; a Colorado brand is on the side and causes a larger value reduction in the handout.

Wool length and pelt value

Longer-wool pelts are more valuable; very short-wool shearling pelts are less valuable.

Titer

The congealing or solidification point of the fatty acids in a fat.

Tallow versus grease

Tallow has a higher titer and grease a lower titer; the handout uses 40 degrees Celsius as the dividing point.

Dry rendering

Heat ruptures fat cells and releases melted fat; moisture is removed and solids are strained from the fat.

Cracklings in rendering

Solid material separated from rendered tallow or grease.

Blood meal production

Fresh blood is coagulated with steam, drained, and dried.

Meat meal production

Made from protein-rich materials recovered during inedible rendering.

Steamed bone meal production

Bones are steam-cooked under pressure to remove remaining fat and meat.

Gelatin source materials

Skins or hides, connective tissues, cartilage, and bones.

Collagen-to-gelatin conversion

Cooking collagen-containing materials in water converts collagen to gelatin.

Glue versus gelatin production

Both use similar animal materials; glue is extracted through successive heatings in water under controlled temperatures.

Adrenal gland: pharmaceutical category

Hormones, including epinephrine from the medulla and adrenocortical extracts from the cortex.

Ovaries: pharmaceutical category

Reproductive hormones, including estrogens and progesterone.

Pancreas: pharmaceutical categories

Insulin and digestive enzymes such as trypsin.

Parathyroid gland: pharmaceutical category

Parathyroid hormone extract.

Pituitary gland: pharmaceutical category

Hormones such as ACTH.

Testes: pharmaceutical category

Enzymes such as hyaluronidase.

Thyroid gland: pharmaceutical category

Hormones such as thyroxine and calcitonin.

Blood: pharmaceutical categories

Albumin and amino acids.

Bone: pharmaceutical category

Minerals, especially calcium and phosphorus.

Intestines: medical-product categories in the handout

Surgical sutures and condoms.

Liver: pharmaceutical categories in the handout

Liver and bile extracts used in pharmaceutical production.

Lungs: pharmaceutical example in the handout

Heparin.

Spinal cord: historical use and note correction

The printed handout lists cholesterol for vitamin D manufacture; a handwritten note flags this use as no longer applicable because of SRM concerns.

Stomach: pharmaceutical and enzyme categories

Calf rennet and pig mucin and pepsin.

Fetal calf blood: use category

Biomedical research.

Aortic valves: medical-use category

Replacement of defective human heart valves.

Fetal pigs: use category

Biology teaching and dissection.

Gallstones: traditional-use category in the handout

Listed as traditionally used as aphrodisiacs; this is a reported use, not evidence of effectiveness.

Common meat-preservation methods

Drying, freezing, salting, and smoking.

Curing

Adding curing ingredients to preserve meat, enhance flavor, and develop cured color.

Major curing ingredients

Salt, sugar, nitrate or nitrite, ascorbate or erythorbate, and phosphates.

Salt in curing

Adds flavor, helps preserve meat, and assists movement of curing ingredients.

Sugar in curing

Adds flavor, counteracts saltiness, and can supply energy for bacteria involved in curing.

Nitrite in curing

Helps develop cured color and flavor, retards rancidity, and inhibits Clostridium botulinum.

Nitrate in curing

Acts as a precursor to nitrite; associated with slow or dry curing in the notes.

Curing-color reaction before heating

Nitric oxide binds myoglobin to form nitric oxide myoglobin.

Curing-color reaction after heating

Heating nitric oxide myoglobin forms nitrosylhemochromogen, the cured pink pigment.

Nitrosylhemochromogen

The pigment responsible for the characteristic pink color of cooked cured meat.

Nitrate-to-nitric-oxide sequence

Nitrate becomes nitrite, then nitrous acid, then nitric oxide.

Nitrate-reducing bacteria in curing

Convert nitrate to nitrite; the notes give Micrococcus aurantiacus as an example.

Backslopping in curing

Transferring old pickle to fresh pickle to introduce nitrate-reducing bacteria, as described in the notes.

Ascorbate and erythorbate

Cure accelerators that speed color development and help stabilize cured color.

Phosphates in curing

Improve moisture retention.

Sodium tripolyphosphate or STPP

A phosphate used for moisture retention; identified as used at Rosenthal.

Water in curing

Dissolves and distributes curing ingredients and can improve juiciness and tenderness.

Protein fat free or PFF

Protein percentage on a fat-free basis; used to classify ham products in relation to retained moisture.

Ham label categories in the notes

Ham; ham with natural juices; ham with water added; ham and water product.