Further processing of meat

SALT, CURING AGENTS, COMMON SPICES, ADDITIVES AND NATURAL SMOKE

Common salt

Common salt (sodium chloride, NaCl, salt) which may be extracted from sea water (sea salt) or mined (rock salt), has three major effects upon meat.

Flavour enhancement of meat and meat products. The salty taste of a meat product depends on the relative amounts of salt and water. Typical ranges of salt concentration for various products are shown in Table 5. Products with less water require higher levels of salt concentration to achieve the same degree of saltiness.

Functional properties of meat proteins. Depending upon its concentration salt can increase or decrease the WHC of a meat product. The dehydrating effect of salt is used for meat drying (lowering WHC). The opposite effect of increasing WHC is very important and results from the swelling and solubilizing of the muscle proteins (actin and myosin).

137. Samples of different nonmeat substances used in manufacturing sausages and other meat products: 1 salt; 2 nitrite; 3 nitrate; 4 nitrite salt; 5 phosphate; 6 ascorbate; 7 GDL; 8 glutamate

TABLE 4
Approximate chemical composition of different qualities of raw materials

Raw materials	Water	Fat	Protein
			Muscle	Connective tissue	Total
Meat I	71	10	16	3	19
Meat II	63	20	12	5	17
Lean trimmings	53	33	10	2	12
Fat trimmings	30	60	7	2	9
External beef fat	27	67	1	5	6
Internal beef fat	5	93	–	2	2
Jowl	17	78	3	3	6
Back fat	8	90	–	2	2
Side fat	32	60	7	1	8
Soft fat	5	93	–	3	3
Pork skin	55	15	0	30	30

 

138. Samples of different common spices in sausage seasoning: 1 black pepper; 2 white pepper; 3 onion in powder; 4 coriander; 5 anise; 6 paprika

TABLE 5
Typical concentration of salt in some meat products

Finished meat products	Range of salt concentration (%)
Sausages
fresh and cooked	1.6–2.2
dry, small-diameter	2.4–3.8
dry, large-diameter	3.0–5.0
Hams
cooked	2.6–3.2
dry	2.5–6.0

Preservation. Salt is one of the most important food additives in food preservation. The salt concentration determines what types of microorganism, if any, can grow by dehydrating or by lowering the amount of water available for growth.

Curing agents

Nitrates. Sodium (NaNO₃) or potassium nitrate (saltpeter, KNO₃) allow cured meat colour to develop in products where drying is a long-term process (Fig. 137). Nowadays, they are used less frequently because to be effective they have to be reduced to nitrites under the influence of bacterial enzymes, and this is a time-consuming process.

Nitrites are indispensable for meat curing, and no substitute has yet been found. Sodium nitrite (NaNO₂), a toxic substance, can be fatal even in small doses (Fig. 139). For this reason they are often mixed with common salt at a concentration of about 0.6 percent (so-called “nitrite salt”) when used for curing. If excessive levels of nitrite are accidently reached the accompanying salty taste will be rejected by the consumer, thereby preventing nitrite poisoning.

The maximum amount of nitrite permitted in finished meat products is usually 200 ppm (parts per million, or mg per kg), or may be less subject to the type of meat product or country legislation. Saltpeter can be added to the nitrite salt at a concentration of 1 percent and used for curing dry hams and dry sausages. Typical levels of nitrite and nitrate in meat products are shown in Table 6.

TABLE 6
Typical amounts of nitrite and nitrate in cured products

Curing agents	Amount of nitrite or nitrate in cured-meat products
Nitrite salt (99.4% NaCl + 0.6% NaNO2)	all-meat products, 100 ppm as nitrite dry hams, 150 ppm as nitrite
Saltpeter (KNO3)	dry sausages, 100 ppm as nitrate low-sodium products, 100 ppm as nitrate
Nitrite salt + saltpeter	dry hams, 600 ppm as nitrate

Three processes in meat curing are due to the effect of nitrites:

Cured-meat colour development is achieved when the muscle pigment (myoglobin) in an acid environment combines with nitric oxide (NO) (formed from nitrite) to form NO myoglobin. This reaction is affected by temperature, pH and oxygen-reducing agents. NO-myoglobin is relatively resistant to light and oxygen and, most importantly, it is heat stable. Thus, cured cooked meat and meat products maintain a bright red colour in contrast to uncured meat which turns grey after cooking.

Nowadays it is considered that 3–50 ppm is sufficient to achieve colour in cooked sausages.

Cured-meat flavour development is based on various reactions between nitrite and the meat component. Typical flavour of cured-meat products is achieved with 20–40 ppm nitrite.

Preservative effect. Even in small doses (80–150 ppm), nitrite prevents the growth of numerous micro-organisms, and food-poisoning bacteria (Clostridium botulinum, salmonella, staphylococci, etc.). However, the effect of nitrite on shelf-life or prevention of food-poisoning bacterial growth must not be overestimated and decreases with increasing storage temperature.

Common spices

Spices act on the salivary and gastric glands to promote secretion, stimulating appetite and improving digestibility of meat products (Fig. 138). Their use varies from country to country depending on the climate, customs and eating habits. There are spices whose taste and smell remain unchanged even after exposure to high temperatures (chilies and sage). Less resistant are cardamom, clove, pepper, rosemary and thyme, and the least heatresistant are coriander, mace, marjoram, nutmeg, allspice and ginger.

Useful additives

Phosphates are used to restore WHC to chilled meat, approximately to the same level as hot-boned meat. Certain countries forbid phosphates, whereas some allow their use only where there is a proven technological effect. Where permitted they should be restricted to 0.3–0.5 percent of the sausage mixture weight. Phosphates break down actomyosin into actin and myosin, which can be solubilized by salt to increase the WHC. This effect is retained even in cooked products, increasing the yield.

Ascorbic acid (vitamin C) and its salts (sodium ascorbate) contribute to the development of cured-meat colour.

Sodium ascorbate is used in the manufacture of cooked sausages, made from uncooked or precooked raw materials. Ascorbic acid used is at a concentration of 0.03–0.05 percent, whereas sodium ascorbate is added at a concentration of 0.07 percent. Ascorbic acid is a strong reducing agent, enabling quicker formation of the NO-myoglobin so that less nitrite is needed, and it inhibits the formation of an undesirable colour in cured-meat products. It must not be added to, or mixed with nitrites, because they will be broken down instantly and will become useless for curing. Thus, the nitrite salt must be added to meat at the very beginning, whereas ascorbic acid is always added at the end of comminution.

Ascorbic acid decomposes rapidly especially in a humid warm environment. Its salt (sodium ascorbate), being more stable, is often used in sausage production, as is erythorbic acid and its salt (sodium erythorbate).

Glutamates. Monosodium glutamate and other salts of glutamic acid are substances which improve the flavour of meat products, and are usually added in concentrations up to 0.2 percent.

TABLE 7
List of common spices used in sausage seasoning (g/kg sausage mixture)

Spice	Dry sausages	Made of raw material
		Precooked	Uncooked
Allspice	0.5–1.0	0.3–0.5	0.1–1.0
Anise	–	0.1–0.3	–
Bay leaves	0.01	0.05–0.1	–
Caraway seed	0.2–1.5	0.2–0.7	–
Cardamon	0.1–0.5	0.2–0.5	0.3–0.5
Cinnamon	–	0.05–0.2	–
Cloves	0.2–0.5	0.1–0.3	0.3–0.5
Coriander	0.3–0.5	0.3–1.0	0.2–1.0
Cumin seed	0.1–0.5	0.2–1.5	0.2–0.7
Ginger	0.1–0.3	0.3–1.0	0.3–0.5
Mace	0.1–1.1	0.3–1.0	0.3–2.0
Marjoram	0.2–0.3	0.5–2.0	0.2–1.0
Nutmeg	0.2–0.5	0.3–1.0	0.3–1.0
Paprika	0.1–1.0	0.4–1.0	0.5–2.0
Pepper	1.0–4.0	1.5–3.0	1.0–4.0
Sage	0.05–0.5	0.1–0.3	0.05–0.5
Tarragon	–	0.1–0.3	0.05–0.5
Thyme	–	0.1–0.3	0.1–0.3
Garlic	according to taste	according to taste
Onion	–	according to taste
Mustard seed	0.5–2.0	0.1–0.2

Natural smoke

Natural smoke is a very complex mixture, consisting of a great number of compounds, and is obtained by controlled combustion of moist sawdust at low temperature. Sawdust from hardwoods is most commonly used to generate the smoke. Nowadays, it is considered that optimal smoke composition is obtained at temperatures of 300–500°C.

Smoke consists of gases (phenols, organic acids, carboniles and other compounds) and particles (pitch, tar, ash and soot). Gaseous components penetrate into a product through the casing to a certain level, and react with other components of meat products. Other components are deposited on to the surface. Smoke provides typical flavour and distinctive colour, and hardens the surface of the meat product.

General remarks

All substances which are added to meat products must have food grade purity. They should not contain any food-poisoning bacteria, so must be treated according to the highest hygienic standards. It is important to keep them in properly closed containers or intact packages, away from any dampness and dust. They are usually kept in special, dry premises away from the workshop, in which they can be pre-weighed, blended and packed into plastic bags in the proportions required for sausage formulations. The nitrate must be kept under lock and key (Figs 139 and 140).

139. Nitrite and nitrate stored locked in metallic containers (access only for authorized personnel because of toxicity of substances in higher concentrations)	140. Storage of different nonmeat substances and spice mixtures (dosage by scales for sausage formulation in waterproof plastic bags)

Dosage by hand of any non-meat ingredient is not allowed (Fig. 141). The only correct way is with scales which must be checked occasionally for accuracy (Fig. 142).

One of the most serious consequences of failure to protect all non-meat substances is contamination with dirt, excreta from rodents, birds or other animals and infestation with insects (Fig. 143).

141. Improper handling: dosage by hand	143. Impurities of common salt
	142. Correct handling: dosage with scales