Curing Meats Naturally
Cured products with claims such as “all-natural” and “no added nitrites or nitrates” are now on the market for consumers interested in such foods. However, curing is an ancient processing technology resulting in safer meats with longer shelflives. The challenge is to produce natural products that still possess characteristics that make them safer than uncured meats that may be mishandled by customers. One conference speaker offered suggestions on how this can be accomplished.

Regulations do not define a “natural” product. However, there is some understanding as to what ingredients are or are not acceptable for such items. For example, the retailer Whole Foods has a formal Unacceptable Ingredient List for products sold in their stores, noted James Lamkey, applications manager, meat and poultry, Chr. Hansen Inc. [Editors’ note: Symrise has since purchased the flavor division of Chr. Hansen, and Lamkey is now with Symrise.]

Curing involves meat myoglobin (which has a fresh red color) reacting with nitric oxide (NO) to form nitric oxide myoglobin (which has a bright pink color). When heat is applied, the nitric oxide myoglobin becomes nitrosohemochrome, and the meat takes on a typical, cured pink color.

Meat processors have the option of using ingredients such as sea salt, starter cultures, sodium lactate (from corn), lemon juice, and buffered equivalents and cherry powder to provide functionalities, when certain additives are shied away from in efforts to provide ingredients perceived to be more natural than their alternatives.

Processors typically provide nitric oxide through the addition of sodium nitrite (NaNO2) or sodium nitrate (NaNO3). Sodium nitrate, only allowed in dry-cured meat products, is then reduced to sodium nitrite during curing through bacterial enzymes. An acidic environment turns the sodium nitrite to nitrous acid (HNO2) that undergoes a chemical reaction to form the needed nitric oxide.

Historically, curing took place when the saltpeter (potassium nitrate or KNO3, an impurity in the salt used in the preservation, or “salting,” of meats and fish) converted to nitrite (NO2) by wild microorganisms. Nitrites are not as stable as nitrates, and, therefore, are not readily available in nature. Nitrates, however, are a part of the nitrogen cycle and are widely prevalent in soil and plant material, said Lamkey.

To naturally cure meat, two components are required. The first is a naturally occurring nitrate source that is found in many plants and vegetable juices. The second component is select microorganisms capable of reducing nitrate to nitrite within normal meat processing steps. Toward this end, for example, brine for a whole-muscle meat could be composed of ingredients such as sea salt, turbinado sugar, spices, natural flavoring (celery juice powder, which is also a source of natural nitrates) and a lactic acid starter culture to reduce the nitrate to nitrite. Typically, the meat is pumped to 20-35%, macerated, vacuum-tumbled, stuffed or compacted, and processed with a normal cook cycle.

The speaker noted that a proprietary, nitrate-providing celery powder is available specifically for this use. Its usage rate is 0.25-0.40 of total batch or injected weight. Thus, the calculation for a ham at 30% pump would be: 0.0025/0.3 X 1.3 X 100=1.1lbs required for 100lbs of pickle at 30% injection. The ingredient can be labeled “natural flavoring” or “celery powder.” An added label qualifier is required for such natural nitrate sources as: “Naturally occurring nitrates found in vegetable juices (e.g., celery juice powder, beet juice powder, celery juice concentrate, carrot juice concentrate, etc.).” A label disclaimer is also needed: “No nitrates or nitrites added, except for naturally occurring nitrates found in (celery powder, sea salt or other ingredient previously just mentioned).” If the label declares that no nitrates or nitrites are added, a disclaimer must be added to identify the source of the naturally occurring nitrates and nitrites. The disclaimer should state: “No nitrates or nitrites added, except for that which occurs naturally in (celery juice powder, sea salt or other ingredient previously mentioned),” advised Lamkey.

Staphylococcus carnosusis a lactic acid starter culture used worldwide in meat products. It releases a reductase enzyme that reduces nitrate to nitrite. Used at 0.02% of the total injected product, it is eliminated at internal cooking temperatures of 158-160°F.  It is labeled as “lactic acid starter culture.”

Lamkey discussed a number of processing parameters. Depending upon formulation, product diameter and heat penetration, heat processing steps may need adjustment.  “Small diameter products will need an added step to allow the starter culture to reduce nitrate to nitrite,” he said.

Large diameter items, such as hams, do not require a heat process change due to “come-up time.” Since phosphates are not used in natural products, the brine composition and processing steps (e.g., the active/rest times during vacuum tumbling) may require adjustments. The lack of added phosphates impacts pH. Since protein extraction is just from salt, more surface area is required, and maceration/tenderization and the vacuum- tumbled steps may need adjustment.

Lastly, safety studies that confirmed the ability of this natural preservative system to reduce risk ofClostridium botulinumwere also presented.

“Curing Meat--Naturally,” James W. Lamkey, development/applications manager, Savory Business Unit, Symrise Inc.,
--Summary by Claudia D. O’Donnell, Chief Editor

Phosphate Innovations

While one supplier discussed advances in natural meat processing, another offered processed meat improvements through use of two new phosphates. Providing some background, Eugene Brotsky, senior technical service representative, Innophos Inc., in his presentation, “‘Meat’ New Trends with Innovative Phosphates,” noted pyrophosphates are increasingly being used in processed meats. As the pyrophosphate content in a meat formulation increases, so does protein extraction, which leads to increased texture firmness through enhancement of the protein matrix that binds moisture. The higher a meat’s pH (i.e., altered through incorporation of brines with certain phosphates), the greater its water-holding capacity (WHC), since a higher pH increases the unfolding of protein molecules--exposing more charged, moisture-binding groups.

Besides pH, phosphate type and ionic strength (increased by salt and the phosphate itself) also impact WHC. Greater ionic strength increases WHC by increasing the solubility of the myofibrillar proteins. A greater ionic strength and pyrophosphate use also compensate for lower pH, with its weaker binding.

However, a challenge exists in that, while a higher meat pH is desired for yield, a lower pH is wanted for taste and appearance. In poultry, a lower pH increases whiteness and helps avoid “pinking,” which is mistakenly associated with undercooked meats by some customers. Lower pHs also help reduce a potential “soapy” taste in products and help enhance the curing reaction. By using a stronger phosphate, such as a pyrophosphate, moderate yields can be obtained while avoiding higher pH, said Brotsky. He also reviewed two relatively new ingredients, TCP (tricalcium phosphate) and 3SP, also known as sodium pyrophosphate, trisodium monohydrogen pyrophosphate or trisodium diphosphate.

The pyrophosphate 3SP has a pH of 6.96. It can be formed by reacting SAPP (sodium acid pyrophosphate, pH of 4.3) with TSPP (tetrasodium pyro phosphate, pH of 10.4) or directly in the furnace used to synthesize phosphates. Improved meat products result when 3SP is blended with other phosphates.

One particular slide provided from a company study showed how the performance of TSPP was compared to STP in a model ham system with 20% yield extension. At lower phosphate levels, S3 and TSPP give higher yield per pound of phosphate used than STP. At higher phosphate levels, however, phosphate type is not as important, he noted. (See the chart “Phosphate Levels and Yield.”)

SAPP dissolves well, but is less useful, because of its low pH. However, TSPP’s high pH is beneficial, but is not widely used, because it has very limited solubility, especially with hard water. However, 3SP can be put into saturated 26% brine, and it will still dissolve--while possessing a neutral pH.

Brotsky summarized some of 3SP’s benefits as having good protein extraction at lower pH, as well as very good solubility. Additionally, it is a cost-effective alternative to using TKPP and complex multi-component phosphate blends.

As for regulations, 3SP meets E.U. specifications, and the company received a USDA approval letter in 2003. The ingredient’s bag label is “sodium pyrophosphate” and is labeled in the finished meat product as “sodium phosphate.”

Brotsky noted that several new blends are now available. One blend, with STP and SAPP, has a pH of about 8.1 in a 1% solution. It also dissolves quickly and is completely soluble. The blend helps avoid color problems, such as “tiger striping,” in cured products. This happens when needles are used to inject brine and a localized pH of 9-10 results, while the adjacent meat has a pH of 5.8-6. The alternating areas of high and low pHs produce stripes. The blend also helps avoid the pinking that occurs in poultry at higher pH.

Tricalcium phosphate (TCP) was another new phosphate presented to the USDA for approval. TCP traditionally has been used to calcium-fortify orange juice, but it also lightens poultry meat color. While a lower pH increases the redness reaction in cured products, it increases whiteness in uncured, lightly colored meat poultry by facilitating pigment denaturation. TCP overcomes the “graying effect” from alkaline phosphates. It is completely insoluble at the pH of meat and is flavorless and label-friendly, said Brotsky. USDA regulations allow its use up to 1.5% in comminuted poultry products, with an additional 0.5% of functional phosphates also allowed in the product, says Brotsky. Labeling for calcium enhancement cannot be used, if just the meat is present in the finished product, but can be done if the meat is only a component in a larger product, such as a meal.

In-house company research has looked at the impact of various blends on color, yields of various blends, use levels and processing parameters.

“‘Meat’ New Trends with Innovative Phosphates,” Eugene Brotsky, senior technical service representative, Innophos Inc.,
--Summary by Claudia D. O’Donnell, Chief Editor

Binding Meat with an Alginate System

Other systems for binding raw meats to form high-quality, reformed meat products do not use phosphates or salt. Advantages to one cost-effective, proprietary system presented atPrepared Foods’ R&D Applications Seminar-East include the fact that standard meat processing equipment can be used; binding is achieved in both raw and cooked products; and bound meat pieces are freeze-thaw stable, said David Ortega, technical service manager, International Specialty Products, in his presentation titled, “Alginate System for Binding Raw Meat and Creating Value Added Products Without Salt and Phosphate.” Additionally, there is no specific requirement for sizes of meat pieces used, and while leaner meats are required (maximum 20% fat), many types of meats can be used--such as beef, pork, lamb and some varieties of fish. Higher fat content tends to impair the bind.  Once formed and sliced into portion-controlled pieces, the pieces can be coated, battered, breaded or marinated using standard techniques. Finally, the appearance, cooking and frying losses are similar to that of unbound and processed meat, said Ortega.

The easy-to-use, two-component binder system is different from carrageenan-based systems that utilize salt and phosphate to bind water and increase yields. The first binder part contains sodium alginate, while the second binder part contains encapsulated calcium lactate.

To process, the meat is added to a tumbler followed by water (maximum of 10% based on the weight of the meat, if called for in the formulation, but it is not necessary), which is tumbled until absorbed. Part one of the binder (sodium alginate) is sprinkled over the meat, while it is being mixed. The product is tumbled/mixed for 5-15 minutes to hydrate the alginate. Part two of the binder is sprinkled over the meat, while it continues to mix, in order to disperse the calcium lactate. Less mixing time (about 2-5 minutes) is required for part two, since it only needs to be dispersed, not hydrated. The product is transferred to a stuffer, or formed and refrigerated (or frozen) overnight. Recommended starting use levels for part one is 1% (2% maximum) for beef and pork, and for part two, it is 0.6% (maximum), based on the weight of the meat, for restructured meat products. For ground and formed, raw or cooked poultry pieces, the starting use level is 1.2%, and the maximum levels for part one and two are 1.6% and 1.2%, respectively.      

Phosphates should not be used, as these will impair the bind. Sodium ions weaken the alginate/calcium binding system. Thus, if salt needs to be added to the product, such as in a marinade surrounding the product or injected into it, it is necessary to allow the product to set before coming into contact with the salt. It is also best to combine the salt with a calcium salt (such as calcium chloride) at a salt-to-calcium chloride ratio of about 10 parts salt to one part calcium chloride, said Ortega.

The meat can be formed into rolls, steaks orroulades. The finished product can be chopped and used in meal kits, such as soups and stir-fried varieties. Or, it can be battered and coated with spices using standard techniques.

“Alginate System for Binding Raw Meat and Creating Value Added Products Without Salt and Phosphate,” David Ortega, technical service manager, International Specialty Products,
--Summary by Claudia D. O’Donnell, Chief Editor