Pork quality is a matter pH, says scientist

US scientists are proposing a new way to evaluate pork quality - its pH content.

Research has found a strong correlation between higher pH levels and pork quality, which is leading processors and packers to develop ways to maintain higher pH in their product.

The measurement of pH is the amount of hydrogen ions in a substance and, therefore, its acidity. A higher pH level means less acidity.

This is a major stir-up for the pork industry, which once proudly marketed its product as The Other White Meat - as higher pH level is usually indicated by the darkness of pork.

Ken Prusa is a professor of food science and has been spearheading research at Iowa State University to find ways of improving pork quality. His work has led him to the conclusion that darker pork and higher pH means less acidity - which is the main culprit in meat deterioration, discoloration and watery consistency.

"Through sensory testing, we found pH to be a pretty strong driver of ultimate pork quality," said Prusa. "Higher pH products are more tender, juicy and flavorful."

"It's an opportunity to add value to pork products in the market place," said Prusa. "Producers and packers are hearing more about the pH factor and learning that it's in their best interest to produce products with higher pH."

Research conducted over the past 20 years has identified three contributing factors that processors can control to increase pH levels: genetics, processing and stress levels.

Findings indicate one of the most important measures is to ensure a carcass is chilled rapidly. Chilling preserves the pH levels of pork, which deteriorate quickly in room temperatures.

Prusa also placed emphasis on the stress an animal undergoes before being slaughtered. Stress increases the metabolism rate, which in turn pushes a larger amount of adrenaline through the body. This natural process has been shown to increase the acidity in muscles.

There is a trend, in Japan especially, to purchase pork on a basis of their pH levels. The increasing demand by retailers around the world is beginning to have an effect on processors and packers who are moving towards buying pigs based on their pH levels, said Prusa. Some packers are at the point of routinely measuring pH on the production line.

To Prusa, this is a small step toward improving the overall quality of pork available to consumers.

"We hope that through our work with packers and processors, we'll see higher pH products on the market soon. We're looking at ways of marketing products on the basis of the deeper, richer colour and flavour," Prusa said. "People can see the difference. Once they taste it, the better quality is obvious."