Patent Description:
The color of fresh meat is one the most important evaluation parameters consumers use when purchasing. For many years, high-pressure processing (HPP) has been used to eliminate pathogens and harmful bacteria in many food and beverage products. HPP is the application of isostatic pressure to a product sealed in a container ("vacuum packed" or "vacuum sealed") and submerged in water at pressures between about <NUM>-<NUM> MPa (<NUM> and <NUM>,<NUM> pounds per square inch (psi)) and typically about <NUM> MPa (<NUM>,<NUM> psi) for varying times, is used to destroy harmful pathogens and bacteria.

As explained by the Food Safety Inspection Service (FSIS) of the U. Department of Agriculture (USDA) in directive <NUM>:
HPP subjects food to elevated pressures, with or without the addition of heat, to inactivate microorganisms and extend microbiological shelf life. Product processed with HPP is placed in a sealed flexible container. The flexible container is placed in a basket or barrel and moved to a high-pressure chamber filled with a pressure-transmitting fluid, usually water that does not contact product. The chamber is equipped with pumping and decompression systems. The action of the high pressure causes the microorganism cell walls to rupture resulting in injury or death. Depending upon length of time the product is subjected to pressure, some or all of the microorganisms might be affected. In addition, changes in the product could occur such as distortion of the shape of the product, as well as reduction in its capacity to retain moisture (purge) because of the rupture of the cell walls.

Thus, HPP can be summarized as pressure treating meat by application of pressure to the meat at a sufficiently high pressure, a selected and controlled temperature, and for a duration sufficient to rupture the cell walls of at least some microorganisms present in the meat. HPP is applied to both fresh or raw and cooked or cured meat products, including ready-to-eat products.

The principal advantage of products that have been treated with HPP is longer shelf life - up to <NUM>-<NUM> times that of untreated products. Extending shelf life results in less food waste and more time to market products. Further, USDA considers HPP a "lethality step" per the FSIS directive <NUM>. Products exposed to a lethality step may be exempt from some labeling exemptions and regulations. These exemptions result in cost savings and competitive advantages.

HPP eliminates pathogens such as e. coli, salmonella and listeria, among others and provides food safety benefits. Because HPP destroys microorganisms which cause spoilage, the flavor profile is extended as well.

Despite all of its advantages, one of the characteristics of meat that has been through HPP is that the meat changes color. In ready-to-eat meats, this color change is not very noticeable, but in others the color change is more severe. Ground meat has been one of the items that the color is changed so much that the consumers have not accepted it. The color of fresh ground beef is much lighter shade of red almost pink or opaque in some cases. Because most consumers buy ground beef based on appearance and the color of the meat is a determining factor of their perception of lean content, HPP ground meats have not met consumers' expectations in regards to color. Many have tried to add ingredients and made adjustments to temperature of water and product, time under pressure and varying pressure settings to eliminate or minimize the color change without much success. For example, <NPL> and, <NPL>, relate to High pressure processing of meat products. <NPL>, discloses the use of spray-dried animal plasma in comparison with other binders in canned pet food recipes. Patent documents with numbers <CIT>, <CIT>, <CIT>, and <CIT>, relate to coloring of meat.

The priority documents for this application contain color drawings and/or color photographs including entry into the National Stage in those countries that accept color drawings and/or photographs. Copies of this patent application publication with color drawing(s) will be provided upon request and payment of the necessary fee.

The novel features believed characteristic of the embodiments of the present application are set forth in the appended claims. However, the embodiments themselves, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein:.

Although the pressure values in accompanying drawings are labeled as "PSI," it will be understood that the values for the pressure are actually in KPSI, as referred to in the written description. In addition, the photographs used in <FIG> are representative of the results from using either porcine hemoglobin or bovine hemoglobin in carrying out the procedures according to the present application.

While the method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, combinations, and alternatives of the present application as defined by the appended claims.

Illustrative embodiments of the disclosed method for improving the color of HPP-treated meat products are provided below.

The color of HPP-treated meat products may be improved by the addition of hemoglobin, which may or may not contain red blood cells, to the meat prior to HPP treatment. According to one embodiment, about <NUM>% to about <NUM>% by weight of hemoglobin is mixed or kneaded into raw meat before HPP treatment. The percentage by weight of hemoglobin will vary depending on the desired color. As the percentage is increased the color will increase in a darker color, until desired color is achieved.

A lesser percentage of hemoglobin may be added to larger quantities, by weight, of meat or to whole-muscle meats. It may be manually or mechanically mixed with the meat or topically applied. The hemoglobin may be added to the meat in liquid form, sprayed dried, freeze dried or otherwise processed into a powdered form and mixed with the meat, or hydrated with water to form a slurry and mixed with the meat.

The hemoglobin is added as a separate processing step prior to HPP treatment. That is, the hemoglobin, alone or with spices, may be mechanically mixed or applied to the meat prior to placing it in a sealed, flexible container, which is in turn HPP processed.

Hemoglobin may be applied to beef, bison, lamb, pork, veal, chicken, turkey, or other poultry, or fish or other seafood, or any meat subject to HPP processing. The meat is fresh (raw). The meat may be ground or processed or whole muscle meat.

Hemoglobin is a pigment material derived from animal blood, which may or may not contain red blood cells. Whole animal blood has many components and these components can be separated by centrifuge equipment or filters. As an example typically whole blood is separated by centrifuge into red blood cells and plasma, the red blood cells can then be separated from the hemoglobin by filtration. As an example, it is commercially available from Sonac Loenen BV, Kanaaldijk Noord <NUM>, <NUM>, P. Box <NUM>, <NUM> AA Son, The Netherlands. It is available in a "stabilized" powder form, Hemoglobin powder 92P, derived by spray drying from porcine blood without active additives. It is also available from Sonac under the "Harimix" brand name mixed with various additives, such as sugar, salt, water, sodium ascorbate, and citric acid. Available from Sonac also is Harimix PB "stabilized" powder hemoglobin derived from bovine blood. The stabilized powder form, without other active ingredients or additives, is preferred, but hemoglobin with additives may be optimal, dependent upon the particular application. Hemoglobin may be derived from the blood of the same species as the meat being treated or from a different species. Dried hemoglobin is also available from Essentia Proteins Solutions, headquarters at <NUM> SE Oak Tree Ankeny, Iowa <NUM> USA under the trade AproRED.

Hemoglobin powder may be kneaded into the meat (for ground meat), applied to the surface of the meat (for muscle meat), or otherwise incorporated in the meat, until the surface of the meat is coated and a homogeneous blend and color is achieved. Hemoglobin powder may be hydrated with water and similarly mixed with the meat. Hemoglobin powder may be hydrated and frozen for storage and then thawed and similarly mixed with or applied to the meat. Hemoglobin in liquid form may be mixed with or applied to the meat with or without freezing for storage and thawing. Hemoglobin or red blood cells may be applied in a non-processed form to achieve similar results.

The following examples are provided by way of illustration of embodiments of the invention and are not intended to limit or constrain the invention. As set forth above, porcine hemoglobin and bovine hemoglobin may be interchanged in the examples below, either one producing very similar results, as represented by <FIG>. Other sources of animal hemoglobin may also be used and may also provide similar results.

Four samples, each of <NUM> grams of <NUM> % lean ground beef, were prepared as follows:.

Each sample was vacuum sealed in a polymer package. Samples <NUM>, <NUM>, and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> HPP apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of about <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for <NUM> seconds. Sample <NUM> was not HPP treated. The resulting packages are shown in <FIG>. As can be visually seen, samples <NUM>, <NUM> and <NUM> exhibit similar bright red color, while sample <NUM> without addition of dried hemoglobin powder is visibly lightened to pink.

Each sample's color was checked and recorded using a Hunter Mini Scan XE spectrophotometer:.

Four samples, each of <NUM> grams of <NUM>% lean ground beef, were prepared as follows:.

Each sample was vacuum sealed in a polymer package. Samples <NUM>, <NUM>, and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for about <NUM> seconds. Sample <NUM> the control was not HPP treated. The resulting packages are shown in <FIG>. As can visually be seen, samples #<NUM>,#<NUM> and #<NUM> exhibit similar bright red colors while sample #<NUM> is without addition of dried hemoglobin powder is visibly lightened in color.

Four samples, each of <NUM> grams of <NUM>% lean chuck ground beef, were prepared as follows:.

Each sample was vacuum sealed in a polymer package. Samples <NUM>, <NUM>, and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of about <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for <NUM> seconds. Sample <NUM> was not HPP treated. The resulting packages are shown in <FIG>. As can be seen, sample <NUM> exhibit bright red color, while sample <NUM> is visibly lighter than sample <NUM>, <NUM>, and <NUM>. While samples <NUM> and <NUM> having additive show to much darker red color.

Three samples, each of <NUM> grams of boneless pork chop, were prepared as follows:.

Each sample was vacuum-sealed in a polymer package. Samples <NUM> and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of about <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for <NUM> seconds. Sample <NUM> was not HPP treated. The resulting packages are shown in <FIG>. As you can see sample <NUM> has a darker natural meat color, sample <NUM> color is opaque almost white while sample <NUM> is a darker natural meat color as opposed to sample <NUM> and slightly lighter than sample <NUM>.

Three samples, each of <NUM> grams of Italian pork sausage King Soopers (TM) brand, were prepared as follows:.

Each sample was vacuum-sealed in a polymer package. Samples <NUM> and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of about <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for <NUM> seconds. Sample <NUM> was not HPP treated. The resulting packages are shown in <FIG>. As you can see, sample <NUM> has a natural meat color, sample <NUM> has a lighter color, and sample <NUM> is a darker natural meat color than sample <NUM>.

Four samples each of <NUM> grams of Pork Breakfast Sausage Kroger (TM) brand, were prepared as follows:.

Each sample was vacuum-sealed in a polymer package. Samples <NUM>, <NUM> and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of about <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for <NUM> seconds. Sample <NUM> was not HPP treated. The resulting packages are shown in <FIG>. As you can visually see sample <NUM> has a natural meat color, sample <NUM> has a similar natural meat color, sample <NUM> is a lighter natural meat color than sample <NUM>, sample <NUM> has a much lighter opaque color with little to no red pigment color.

Four samples each of <NUM> grams of chicken breast Heritage Farm (TM) brand, were prepared as follows:.

Each sample was vacuum-sealed in a polymer package. Samples <NUM>, <NUM> and <NUM> were then subjected to HPP treatment in an Avure QFP <NUM>-<NUM> apparatus at about <NUM> MPa (<NUM>,<NUM> psi) and a temperature of about <NUM>-<NUM> (<NUM>-<NUM> degrees Fahrenheit) for <NUM> seconds. Sample <NUM> was not HPP treated. The resulting packages are shown in <FIG>. As you can see sample <NUM> has a natural poultry meat color, sample <NUM> has a similar to slightly lighter natural meat color, sample <NUM> is a lighter meat color than sample <NUM> and <NUM>, sample <NUM> has a much lighter opaque to no color.

These examples demonstrate that the application of hemoglobin to meat prior to HPP processing assists in preserving pleasant color in the meat. The use of hemoglobin to preserve the color of meats may be used with any variant of the HPP process. Typical parameters for the HPP process is from about <NUM> to <NUM> MPa (<NUM>,<NUM> to <NUM>,<NUM> psi) pressure, and temperatures from about <NUM>-<NUM> (<NUM> degrees to about <NUM> degree Fahrenheit). The duration of application of pressure is usually <NUM> to <NUM> or several minutes, but less than an hour.

It will be appreciated that the process of the products, methods, and processes of the present application include the added benefit of fortifying the meat with iron.

It should be understood that the present application covers the following processes: (<NUM>) using animal blood, separating hemoglobin from the blood, while some red blood cells may or may not remain, converting the hemoglobin into a dried form, hydrating the dried hemoglobin, mixing the hydrated hemoglobin with meat, and subjecting the treated meat to a selected and controlled HPP process; (<NUM>) using animal blood, separating hemoglobin from the blood, mixing the undried hemoglobin with meat, and subjecting the treated meat to a selected and controlled HPP process; and (<NUM>) using animal blood, separating hemoglobin from the blood, mixing the hemoglobin, either in dry form or liquid form, mixing other color-retaining ingredients and/or agents into the meat, and subjecting the treated meat to a selected and controlled HPP process.

Claim 1:
A method of pressure treating fresh meat, comprising:
applying hemoglobin to the fresh meat;
placing the fresh meat in a sealed, flexible container prior to pressure treating the fresh meat; and
pressure treating the fresh meat by application of isostatic pressure to the fresh meat at a sufficiently high pressure from about <NUM> MPa ( ee-<NUM>,<NUM> psi) up to about <NUM> MPa ( <NUM>,<NUM> psi), and temperatures from about <NUM> to about <NUM> ( from about <NUM> degrees to about <NUM> degree Fahrenheit), and for a duration of time of <NUM> seconds to less than an hour sufficient to rupture the cell walls of at least some microorganisms present in the fresh meat.