An official website of the United States government.

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Post-Mortem Muscle/Meat Changes that Affect Product Safety and Quality


The objectives of this project are twofold, and both relate to utilizing the structural and biochemical properties of the post-mortem muscles and/or cooked meat to optimize process efficiency, product quality, and safety. The first objective is to optimize finished poultry meat product quality while decreasing processing times and costs, and the second is to develop accurate, simple to use, economical objective procedures to profile post-mortem changes in the muscle/meat system.

More information

The first objective involves a better understanding of the rate of post-mortem interactions of the muscle proteins with non-meat protein additives. Two approaches will be used: different processing avenues for portions (breasts, wings, legs) will be established to optimize functional and textural properties, and the effects rigor state at the time of non-meat ingredient incorporation, and product fabrication on color, moisture binding, and texture will be determined to optimize finished product quality. <P>The second objective involves developing methods to monitor/verify heat treatment that has been applied to products and to profile the progression of product deterioration (rancidity and putrification) prior to consumption. Two different approaches will be used: establish the relationship between structural and functional protein changes during heating to specific temperatures and isolate, identify and quantify causative compounds responsible for deterioration.
PROGRESS: 2000/10 TO 2001/09 <BR>
DUCT SAFETY AND QUALITY<BR> 1. What major problem or issue is being resolved and how are you resolving it? The charge for this team was to optimize processing efficiency and ensure both end-product quality and safety. Two problems/issues were addressed: 1)abbreviate processing times to avoid costs associated with holding carcasses prior to breast muscle removal, 2) develop tests based on enzyme inactivation to accurately monitor and/or later verify the heat treatment applied to poultry meat. Research was focused on optimizing processing, further-processing and packaging of intact parts and fabricated products, with emphasis on breast tissue since it is the economic driver of the industry. Specific objectives were to optimize yield and texture of these parts/products by coordinating production practices such as age at slaughter; postmortem processing factors such as state of rigor and marination techniques; and storage and shipping conditions. Development of methods to identify enzymes that can be used to determine the heat treatment that has ben applied to poultry meat was essential for both industry and regulatory personnel as they try to ensure that consumers have access to products that have been adequately cooked to destroy human pathogens associated with poultry processing and further-processing. <BR> <BR> 2. How serious is the problem? Why does it matter? These issues were of vital importance because the poultry industry and Food Safety Inspection Service (FSIS) were moving toward a science-based approach to processing and inspection (Hazard Analysis & Critical Control Point) concept. Even though these changes are primarily designed to improve product safety, they also have major impact on product quality. There is constant financial pressure for the industry to modify operating procedures to remain competitive in both the domestic and international markets. For example, major processors list breast meat toughness as a major problem/complaint. A typical processing facility slaughters approximately 250,000 birds per day. If front halves or carcasses must be held from 6 to 8 hours prior to muscle removal to ensure optimum tenderness, the refrigerated space, labor and utility costs become prohibitive. If this cost was eliminated, it would save an estimated $5,000,000 per processing plant each year. 3. How does it relate to the National Program(s) and National Component(s)? This CRIS directly addressed Program 108 (Animal Production, Product Value and Safety Category, Food Safety (animal products), and Program 306 (New Uses, Quality & Marketability of Animal & Plant Products. 4. What were the most significant accomplishments this past year?
<BR> <BR>
A. Single Most Significant Accomplishment During FY 2001 Year: <BR> In an effort to improve poultry processing efficiency and reduce costs, a study was conducted to eliminate my post-mortem aging after chilling. We conducted a series of studies in cooperation with a commercial processor in Georgia to determine the effects of electrical stimulation time of muscle removal, and marination on the texture of cooked breast meat. The combination of stimulation, muscle removal after chilling, and marination resulted in acceptable tender cooked mat. This combination can be used to eliminate any additional carcass chilling, thus saving processors the costs of refrigerated space and labor. <BR> <BR> 5. Describe the major accomplishments over the life of the project including their predicted or actual impact. <BR> 1) Cooperative research with the Quality Assessment Research Unit resulted in texture benchmarks for cooked breast meat. The relationship between objective procedures and sensory panels was established. Ranges of tough to tender for each procedure were related to a sensory scale. Objective values relating to the tender portion of the scale are routinely used by industry quality control personnel to ensure process control and product quality. <BR> 2) An in-line apparatus conceived, built, and tested under pilot plant and commercial conditions applies pulsed electric current to carcasses to hasten postmortem biochemical reactions (deplete energy from the fiber) thus making it feasible to remove the large breast muscles without the traditional 6 hour aging time. With stimulation, the aging time can be reduced to 2 hours. <BR> 3) Research established that the onset of rigor mortis could be hastened by subjecting carcasses to pulsed electrical stimulation during bleeding, and that marination of the breast muscles after carcass chilling resulted in acceptable tender breast meat without any further aging. This stimulation/marination treatment allows central preparation of breast meat products at the processing facility in a continuous flow which increases efficiency and reduces costs and handling. It is estimated that the cost savings will be $5,000,000 per plant each year. <BR> 4) Various enzyme based systems were developed to determine adequacy of heating poultry and red meat. Examples include the GOT, PK, and ACP tests. The tests have proved to be accurate to the point that they are being used by both regulatory and industry personnel as integral parts of their Hazard Analysis Critical Control Point (HACCP) approach to science-based inspection. <BR> 5) Cooperative research within the unit resulted in a patented process to tenderize breast meat by removing it from carcasses shortly after slaughter and placing in a clamp to prevent fiber contraction and subsequent toughening. The technique may allow breast meat to be removed earlier in processing instead of aging whole carcasses after chilling (U.S. Patent 6,110,034). <BR> 6) Yield studies in cooperation with University of Georgia faculty showed that bird age has a significant impact on the resultant proportion of parts. Even as feed efficiency declines as age increases, the proportion of meatier parts increases. Moreover, age also affects texture of early-harvested breast fillets. Early-harvested breast meat from younger birds was more tender than that of older birds. This information allows processors to designate specific marketing avenues based on bird age while minimizing process changes. <BR> 7) Studies established that significant losses due to package overfilling of breast fillets could be reduced by initially weight categorizing the fillets then filling the packages by count instead of absolute weight. This results in a finite and known proportion of underweight packages, and that proportion can be controlled within acceptable levels. <BR> <BR> 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product? <BR> 1) The specifics of the apparatus designed to stimulate carcasses during bleeding was transferred to domestic poultry companies and is either in use or is being tested in at least 24 plants and a company in Brazil. An equipment company has used the concept to market a commercial version of the stimulator. Many of the processing companies are making their own in-house version of the stimulator based on information provided by unit scientists.<BR> 2) The enzyme kits developed to measure heat treatment in domestically produced poultry and imported beef products were transferred to a private sector cooperator, FSIS, and APHIS (GOT test). <BR> <BR> Lyon, C.E. Invited participate at the Georgia Poultry Federation Spring Meetings and Summer Executive Board Meetings. 1996-200. <BR> Lyon, C.E. Invited participant to ARS National Food Safety Workshop (NP 108) addressing Post-harvest Meat Slaughter. 1999. <BR> Lyon, C.E. ARS Presenter (Overview of ARS Meat Research) at National Program 306 Workshop, New Uses, Quality and Marketability of Plant and Animal Products. 1999.<BR> Lyon, C.E. Invited speaker at Annual Research and Development Meeting, Tyson Foods, Inc. Presentation: Current Areas of Research and Opportunities for Cooperation. 1999.

Lyon, Clyde
USDA - Agricultural Research Service
Start date
End date
Project number
Accession number