Processing and Preservation of Meat-Derived Products

Numerous products are derived from meat processing, varying from country to country and from location to location within a country.

Production of Comminuted Meat Products

Finely chopped or blended meat products constitute a group of foods denoted as comminuted meat products. These products are mostly made from meat cuts, lower-grade carcasses, meat by-products, and a filler or binder.

Typical fillers include processed wheat flour, bakery products, milk or whey powder, and starch. The mixture of filler with a carbohydrate source, salt, spices, egg white or other gelling agents, and a preservative such as sodium nitrite is defined as a binder.

Numerous calculations determine the amount of each constituent utilized in the product. The least-cost formulation takes the form of a series of linear equations.

Successful formulation depends on the availability of accurate information about the properties and composition of potential raw materials that may be included. The formulation process must determine the extent to which substitutions can be made and when it would be most economical to do so.

Read Also: The Health Benefits of Using Beef Stew Spices on your Cooking

Production Process of Kilishi

Kilishi is a special, sun-dried beef snack that can be stored for up to six months at ambient temperature. The meat must be prepared quickly to prevent bacterial growth. As the product is not cooked, it should be processed hygienically to prevent the risk of food poisoning.

1. Equipment for Kilishi Production

1. Drying racks
2. Pestle and mortar

2. Kilishi Production Process

1. Meat Selection: Meat from any healthy cattle can be used.
2. Separate Fat: Cut off the fat using a sharp knife.
3. Cut Meat: Cut the meat into thin slices, 1–2 cm thick.
4. Wash Meat: Wash in clean water.
5. Mix Spices: Add mixed spices to the strips.
6. Pound Mixture: Pound the meat-spice mixture with a pestle into thin sheets.
7. Dry Product: Dry in the sun on drying racks for 2–3 days to about 5% moisture.
8. Packaging: Store Kilishi in jute bags. It is sold from bowls, wrapped in paper. The meat is not packaged but is cut into different-sized pieces depending on the price paid.

3. Process Notes for Kilishi

Preservation is primarily due to low moisture content, with spices providing an antimicrobial effect.

Production of Gelatin from Bone

Gelatin is a cream/brown powder used as a thickening or gelling agent for table jelly and a wide range of confectionery. It is also used to clarify wines, with a shelf life of several months depending on packaging and storage conditions.

1. Raw Materials for Gelatin

The yield of gelatin is determined by the amount of cartilage and collagen in the bones. Bones should be fresh and free from gross contamination by soil or bacteria. Leg bones and joints are typically selected due to their high collagen content.

2. Equipment for Gelatin Production

• Filter bags
• Grinding mill
• Heat sealer

3. Gelatin Production Process

i. Bone Selection: Use fresh meat bones and tendons containing more cartilaginous tissue.

ii. Clean Bones: Remove all meat from the bones by scraping, retaining cartilage tissues.

iii. Chop Bones: Break bones into manageable pieces using choppers.

iv. Heat Bones: Boil gently for 5–6 hours.

v. Cool Mixture: Cool to room temperature.

vi. Separate Fat: Remove floating solid, fried fat.

vii. Filter Solids: Decant clear liquid to separate from the layer of solids at the base.

viii. Concentrate Liquid: Gently simmer to boil off water until the liquid is thick and viscous.

ix. Dry Gelatin: Sun-dry in thin layers on metal sheets until dried and crisp.

x. Grind Product: Pound using a mortar and pestle or a manually operated mill.

xi. Pack Product: Package in sealed polythene bags.

xii. Store Product: Store in a cool, dry place.

4. Process Control for Gelatin

Hot water extracts gelatin and sterilizes the product. The time and temperature of heating determine the yield. Evaporation and drying should be done quickly to prevent microbial growth before the gelatin is fully dried.

The thickness of the gelatin layer and drying conditions primarily determine drying time. The extent of grinding and sieving determines the fineness of the final product.

5. Packaging and Storage of Gelatin

The product is hygroscopic and should be quickly packaged in moisture-proof, clean containers and stored in a cool, dry place.

Read Also: Concept and Categories of Meat

Production of Canned Meat

Canning is one of three major modern food preservation methods (canning, freezing, and dehydration). It was the first to be carried out on an industrial scale and remains the most reliable method, completely destroying enzymes and microorganisms.

Sterilization is the most accurate description of this method, as glass jars, bottles, and similar containers may replace cans, for example, in preserving meat and fish pastes and bottling beverages. Practically every kind of food can be preserved by this method meats, fish, vegetables, fruits, and drinks.

1. History of Canning

Present-day canning stems from the work of Nicolas Appert, who in the 1870s discovered that food hermetically sealed in glass jars and heated for an adequate time remained wholesome. Unaware of bacterial activity, Appert incorrectly assumed success depended on the complete exclusion of air.

The large-scale canning industry developed in America during the Civil War and in England during World War I to feed troops. The discovery of the modern sanitary can is the most significant historical event in canning.

2. Principles of Canning

The general principles of canning are:

1. Place food in a sealed container to prevent further bacteria and microorganisms from entering.
2. Heat the container sufficiently to destroy any microorganisms present. Strong heating is critical to eliminate heat-resistant spore-formers.

3. Canning Manufacturing Process

i. Preparation: Sort, grade, and wash raw food to be canned.

ii. Blanching: Apply heat treatment in hot water or steam at 90–100°C for 1–5 minutes to destroy or inactivate enzymes, reduce initial microbial load, remove gas from plant tissues, relax tissues, and facilitate filling.

iii. Filling: Place food pieces into cans with a liquid (brine, oil, or syrup) to aid heat transmission during sterilization. Lacquered cans are often used for processed fruits and vegetables, except for products like carrots, which develop off-flavors in lacquered cans. Lacquers are non-toxic organic coatings applied to tin plates before forming cans. External can surfaces may be sprayed with corrosion-resistant lacquers. Vegetables, being low-acid foods, are processed at very high temperatures, requiring lacquers like epoxy or phenolic resins to withstand the heat.

iv. Exhausting: Pass cans through an exhausting line to remove air, forming a vacuum in the headspace to prevent microbial growth and oxidative rancidity.

v. Sealing: Hermetically seal the container with a specially fitting lid that drops over the edge, spun in a sealing machine until the edges curl together and are rolled flat. A hermetically sealed container is impermeable to gases and water vapor throughout its body, including seams, preventing entry of bacteria, yeasts, molds, and dirt. It protects against moisture gain or loss and oxygen pickup, suitable for strict vacuum and pressure packaging. Rigid metal cans and glass bottles are common hermetic containers, though faulty closures can render them non-hermetic. Glass bottles fail more often than cans in maintaining hermetic seals.

vi. Sterilization: Sterilize the product immediately after sealing to eliminate or kill all forms of life, including transmissible agents (fungi, bacteria, viruses, spores, etc.). Sterilization can be achieved through heat, chemicals, irradiation, high pressure, filtration, or combinations thereof. The aim is to reduce initially present microorganisms or pathogens, expressed by multiples of the decimal reduction time (time needed to reduce the initial number to one-tenth). Autoclaves use steam heated to 121–134°C (250–273°F) at 100 kPa (15 psi) for at least 15 minutes at 121°C or 3 minutes at 134°C. Additional time is required for liquids or instruments packed in cloth layers. Liquids in pressurized autoclaves must cool slowly to avoid boiling over. Modern converters depress the sterilization chamber gradually, allowing liquids to evaporate under negative pressure while cooling. Dry heat sterilization, used for powders and heat-stable items, requires at least two hours at 160°C (320°F) or 6–12 minutes at 190°C (374°F) for unwrapped or wrapped objects, respectively.

vii. Batch Processing: Batch steam retorts, often vertical, are used. Baskets containing the product are loaded, and the lid is secured. Steam enters through a distribution spreader at the bottom, with the vent valve open until the retort reaches a minimum temperature to purge air. The vent is then closed, and the retort is brought to the desired processing temperature. Heat transfers by conduction from steam to the can, with contents heating by convection (for liquids like soups) or conduction (for solid contents like meat). Cooling water floods the retort at the end, and cans are cooled under water, labeled, packaged, and warehoused.

4. Advantages of Canning

Canning effectively destroys bacteria, and no special storage conditions are required for the finished product.

5. Disadvantages of Canning

The weight of cans increases transport costs, and strong heat treatment limits its application to foods consumed in cooked form.

Advances in Meat Sausage Processing

Cured meats, and to a lesser extent uncured meats, are used in vast quantities of sausage products, with over 200 varieties. Classification is complex but generally includes:

1. Fresh sausage
2. Uncooked smoked sausage
3. Cooked smoked sausage
4. Dry sausage

1. Sausage Production Process

Meat chunks of variable size, shape, and fat content are ground to form uniform cylinders of fat and lean, then tumbled in a mixer for uniform distribution. The mixture is subjected to an emulsifier, combining grinding and chopping to emulsify the meat product.

The sausage emulsion, also known as mix, sausage dough, or batter, is transferred to a stuffer for extrusion into casings. Three types of stuffers are used: piston and pump in a single unit.

The encased mass is tied with thread or fastened with metal clips. For small sausages like frankfurters, stuffed casings are twisted or drawn together to produce links by hand or mechanical devices.

i. Fresh Sausages: Links are separated and chilled prior to packaging.

ii. Cooked and Smoked Sausages: Links are hung on sticks manually or automatically, placed on smokehouse racks, or sent through a continuous processing system. Cooking and smoking schedules vary, ensuring the entire product reaches at least 68°C. Examples include Frankfurter, Bologna, Braunschweiger, Genoa, Gothenburg, Lyons, and Arles, named after European cities or regions where they originated during the Middle Ages.

2. Types of Sausages

i. Fresh Sausage: Made from selected cuts of fresh meats, primarily pork but sometimes beef, not previously cured. It must be refrigerated and cooked thoroughly before serving. Examples include fresh pork sausage and fresh country-style pork sausage.

ii. Uncooked Smoked Sausage: Similar to fresh pork sausage but subjected to a mild cure, placed in natural hog or collagen casings, and smoked. It requires refrigeration and cooking before marketing unless made from trichina-free pork. An example is Polish sausage (kielbasa).

iii. Cooked Smoked Sausage: The most popular type in many countries, representing about 30% of all sausages. Usually cured, flavored, and spiced, links are hung on sticks and placed on smokehouse racks or processed continuously, cooked to at least 68°C. Examples include ham-style bologna, German-type mortadella, and liver sausage.

iv. Dry Sausage: Classified into dry and semi-dry types. Semi-dry sausages lose 8–15% of original weight through processing and drying, while true dry sausages lose 25–40%. All are fermented by lactic acid bacteria, often using starter cultures or chemical lactic acid sources. Drying is achieved with a controlled air-conditioning system to remove water.

Spoilage of Meat Sausages

One of the earliest signs of meat spoilage is a potent rancid odor, affecting all spoiled meat, including seafood, which smells “fishy” when spoiled. No meat seafood, poultry, or red should have a detectable foul smell; if present, it is unsafe for consumption, and quick removal from storage prevents odor spread.

Microbial activity during spoilage may cause molds and an unusual texture, with spoiled red and poultry meat showing molds and a mucus-like, sticky, or slimy coating. Discoloration is another vital sign of spoilage; fresh meat should be pinkish-red or colorless. Grayish, greenish, or black colors indicate it is unsafe.

For packaged meat, the expiration date is a quick way to detect spoilage. The average shelf life for raw red meat is 1–3 days and 7–10 days for cooked meat.

Storage Guidelines for Sausages

Freezing is an excellent way to prolong meat lifespan, preserving taste and freshness. Storage methods include:

i. Refrigerate: Store sausages in original packaging until use.

ii. Seal After Opening: Seal opened sausages in a food storage zipper bag or food protection container.

iii. Refrigerate Cooked Sausages: Store in shallow airtight containers or wrap tightly with heavy-duty aluminum foil or plastic wrap.

1. Storage Periods for Sausages

1. Properly stored cooked sausages last 3–4 days in the refrigerator.
2. Properly stored, they maintain best quality for 1–2 months in the freezer but remain safe beyond that time.
3. Sausages kept constantly frozen at 0°F remain safe indefinitely.

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