The definition of pork quality is painted with a broad brush. Depending on who you ask, they may define it as lean quantity, food safety, environmental acceptability, human nutritive value, absence of residues, pH, color, marbling and water holding capacity (WHC). For this discussion, we'll narrow the definition to the attributes of pH, color and WHC.

Superior pork quality can be defined as having the following attributes:

* The ideal pH range is 5.6-6.0. Pork with a pH below 5.6 is likely to have reduced WHC and an unacceptably pale color. Pork with a pH greater than 6.0 may be too dark in color. WHC does not continue to improve above 6.0.

* Ideal fresh pork color is a No. 4 on the new National Pork Producers Council (NPPC) color chart. This translates to an objective color score (Minolta L*) of 43.

* Pork processors are enhancing so much fresh pork with moisture to make it more tender and juicy. Therefore, high WHC is very important - less than 1% purge in a vacuum-packaged, boneless loin after 21 days of storage.

The many efforts aimed at improving pork quality have one primary goal - to provide pork products that "delight" the consumer. If we are to succeed in this goal, top quality pork products must be produced from raw material that exhibits superior pork quality traits.

How do you identify a delighted consumer?

We would describe this consumer as one who:

* understands the benefits of a product;

* through experience, trusts the product to always deliver the understood benefits;

* is willing to reward the supply chain for the added value of a great eating experience; and

* keeps coming back for more.

For the pork industry to consistently delight consumers, we must satisfy three key desires:

* First, the pork products must deliver a great eating experience. Above all else, it must taste good.

* Next, the pork must be easy to prepare, and/or the eating experience must be so good that it justifies the time required for preparation.

* Finally, there must be a greater variety of pork products to satisfy the diversity of flavors, eating occasions and serving sizes demanded by consumers from their protein choice.

Fresh pork products that are visually attractive (ideal color, little or no moisture in the package), tender and juicy (due to higher pH and increased WHC) and consistently taste great (able to carry a flavor and/or moisture-enhancing solution because of increased WHC) will certainly delight consumers.

Quality Improvement Tools In order to improve pork quality we must measure it and understand what those measurements mean. Virtually every packer is measuring pork quality with a variety of subjective and/or objective means. The most common include:

* pH: This is most commonly measured in the loin and/or ham 24 hours after slaughter. Some packers also measure pH 45 minutes and 3 hours after slaughter to determine how fast the pH is declining. Measuring pH (especially 24-hours after slaughter) is useful because it's fast, accurate (repeatable), less invasive (product doesn't have to be exposed or damaged) and a good predictor of important product attributes such as color and WHC.

* Color: This is measured subjectively (i.e., using the NPPC color chart, Japanese color chips, etc.). It's also measured objectively (i.e., using machines such as a Minolta colorimeter). The color score (subjective - NPPC color score of 3) and/or color value (i.e., Minolta L* of 45) is then compared against a standard to determine if the product or process is performing as desired.

* WHC: Water holding capacity is often determined by measuring the purge (loose moisture) within a vacuum bag containing a boneless loin. A higher purge level indicates a lower WHC, which results in tough, dry pork.

More specifically, pork quality measurements are being used today for three basic purposes:

* Identify genetic lines with superior pork quality. Measuring pH, color and WHC is helping identify which genetic lines produce the best pork quality. While every packer is evaluating the pork quality traits of different genetic lines, each packer may have a different view about what is the optimal combination of these traits.

* Sort carcasses/primals for optimal end-use utilization. A packer may measure color, pH and WHC to sort primal cuts for particular uses, such as: case-ready products; moisture-enhanced primals (loins, butts, ribs, etc.); export, and satisfying unique requirements of certain customers.

* Process control. Pork quality measurements are being used to monitor the variation of pork quality caused by various production and processing steps (nutrition, handling, rest time, stunning, chilling, etc.).

What Have We Learned? Recent data provides some insight into procedures that have an impact on pork quality. For example:

* Genetics plays the largest role in pork quality. There are definitely genetic lines that will have higher pH, color and WHC values.

* Rough handling during loading and unloading will cause lower 45-minute and 3-hour pHs (faster rate of decline), which results in pale pork with reduced WHC. Even the best genetics can produce inferior pork quality if the hogs have been improperly handled.

* Proper rest times (at least 2 hours, but preferably 4 hours immediately prior to slaughter) will lead to a slower pH after stunning and a higher ultimate pH. The end result is fresh pork with better color/WHC.

* Producers' inputs can affect pork quality. There is variation in pH, color and WHC even between producers using the same genetics.

* Faster carcass chilling improves pork quality.

Again, the overall reason for measuring pork quality is to identify superior quality raw material that will result in value-added pork products which will delight customers. As we look toward the future, to be successful, new pork products will certainly require high quality raw material.

Pork quality measurements will continue to play an important role in our drive to improve the pork quality of the U.S. hog population. Pork products made from high quality raw material are absolutely necessary to delight consumers and grow the profitably of the pork industry.