Lecture 4 Casing sausage containers Utilization of Animal By-products Dr. Fa-Jui Tan 2009 Class handout 1 Casing Sausage casing definition Containers of ground and comminuted meat and sausages The material that contains and encloses the filling of the sausage. natural or manufactured (artificial, synthetic) casing Stuffing: the processing of placing meat products into casing Other uses of animal intestines Surgical sutures, musical instrument string, tennis rackets or pet food, meat meal, fertilizer Characteristics of animal intestines Highly microbiological contaminated Must be carrier out immediately after slaughter of the animal safety & quality concern 2009 Class handout 2 1
Edible casings Kinds of casing animal origin and consist of either natural casings or those manufactured from solubilized regenerated hide collagen Inedible casing Cellulose casing Plastic casing 2009 Class handout 3 Materials Natural casings made from the gastrointestineal tract (small intestine, large intestine) of cattle, hogs and sheep Weasand, urinary bladder, stomach, rectum, made from the submucosa (a layer of the intestine that consists mainly of collagen) Fat and the inner mucosa lining are removed. 2009 Class handout 4 2
Characteristics Edible Use of by-products Natural casings Various in sizes & shapes Very permeable to moisture & smoke Imparting resistance to chewing (providing product specificity) 2009 Class handout 5 Natural casings Shortcomings: difficult to handle (cleaning) labor intensive not uniform in sizes not so easy for industrial producing Be careful: cleaning thoroughly adding extra salt low temp storage 2009 Class handout 6 3
Hog bung Hog stomach Caecum Bladder Beef bung Weasand Other natural casings Remove from the carcass, trimming free of fat, cleaned, washed, turned inside-out, slimmed & packed in salt 2009 Class handout 7 Other uses of intestinal products Casings Edible uses Strings for musical instruments Strings for sports rackets Catgut (surgical ligatures) Mucosa The slime or inner membrane of the casing To make heparin (as an anticoagulant) 2009 Class handout 8 4
Production of natural casings Removing the viscera Care: not to cut the viscera, causing faecal materials to contaminate viscera or carcass Cutting around the anal opening and removing Separating the stomach, lungs, hearts, and livers from the intestine Removing ruffle (mesentery) fat 2009 Class handout 9 Production of natural casings (cont.) Casing pulling station 20-40C water spray to aid By hand (better quality, but labor-intensive) Connective tissue is torn off directly from the casing Manure stripper Fermentation in some areas (but not is US) Casings soaked at 20C water overnight or until the mucous and muscular coating are loosened Soaked in 40C water for 1 hr & stripped again Run through a clean machine 2009 Class handout 10 5
Production of natural casings (cont.) Crusher To break the inner mucosa membrane & separate it from casing 40C soaking tank for 30-45 min Soaking in 15C or ice water or a salt brine tank to remove excess blood. Gathering into a hank: may contain 20-50 pieces of casings Salted (curing) By hand or by machine By hand: medium fine first, fine salt until absorb 40% By machine: less labor needed Package 2009 Class handout 11 Manufacture casings Also known as artificial casings Types Collagen: Reconstituted collagen casing Cellulose Plastic Inedible casing Cellulose casing Plastic casing Changes of properties of casing Depending on characteristics of materials and requirememts E.g. Moisture and heat make casings softer and more porous. 2009 Class handout 12 6
2009 Class handout 13 Collagen casing Specialty bridge between natural & artificial casings man-made products but are constructed from collagen Materials: Collagen Regenerated from collagen extracted from the corium layer of skins & hides Extracted from the corium layer of inspected, soaked, salted and rinsed animal hide (normally beef) and extruded into the shape of a casing 2009 Class handout 14 7
Characteristics of Collagen Casing Uniformity: Very uniform in physical characteristics, Uniform length, diameter, wall thickness, strength Have predicable handling & stuffing characteristics & can be used in programmable wt system Greater strength vs. natural casings Available in various sizes Color: natural color, or smoked color Can be stored indefinitely as long as the storage conditions remain favorable Ready to use (no rewetting is necessary, unless large diameter casings soaking in 25-30C water) Edible (small casings) vs. Inedible (large diameter, treated with aldehyde to cross-link the collagen & increase strength) Storage: Refrigerated storage to prevent bacterial spoilage 2009 Class handout 15 Collagen casing Utilization Edible collagen casing (usually small casings) For fresh, smoked, dried and processed sausages, Fresh pork sausage links, frankfurters Chewable Thin Solubilize in cooking or non-edible, Inedible collagen casing (usually large casings) 2009 Class handout 16 8
Casing evaluation Cleanliness Clean, free from stains, odor, fat particles, parasites without pinhole Strength Strong enough to withstand the pressure exerted on them during filling, stuffing and processing Length Standard length (sheep & hog): 91.4 m (100 yards)/hank Beef: 18m (89 ft) 2009 Class handout 17 Casing evaluation Calibre Desired varies according to types of sausage Uniform casing needed for modern machinery uses Curing Normally salted and cleaned Dried (but might lose the necessary elasticity required in the stuffing operation) Packaging Wooden and plastic containers, tins, plastic bags 2009 Class handout 18 9
Cellulose casings Manufacturing Made from cellulose (prepared from cotton linters or wood pulp) Characteristics & advantages: Manufacturing in various sizes (diameters) Uniformity Ease of use (variety of sizes) Stretch & shrink characteristics similar to those of nature casing May coated with edible dye or natural smoke Low microbial loads 2009 Class handout 19 Plastic tubes or bags Inedible Peeling before eating Characteristics PVDC casing Impermeable to smoke & moisture Used for unsmoked products Good protection against oxidative changes & microbial growth (aerobic MO) 2009 Class handout 20 10