Detecting PSE

In section 8 we identified the cause of PSE as being preslaughter stress (with or without the presence of the Halothane gene) leading to rapid post-mortem pH fall while the carcass was still hot. In this statement we find the means to monitor those carcasses likely to develop PSE.

This can be done by:

·                 Measuring the pH 45 minutes after slaughter (pH₄₅)

·                 Measuring the change in electrical conductivity in the muscle, or

·                 Measuring the reflectance of light in the muscle.

It cannot be done by measuring the ultimate pH (pH_u), which will be the same for PSE and non-PSE carcasses.

In New Zealand the only method routinely used, and certainly the one adopted by Murrellen Pork, is to measure the rate of pH fall at pH₄₅. This is in spite of the fact that the method most widely used in Canada and the EU is the Hennessey Reflectance probe, a product of New Zealand.

Post-Mortem

The following graph shows the comparative pH fall in a normal vs. a PSE pig.

Figure 9: pH falls PSE vs. Normal

Murrellen Pork is slaughtered at Bay City Meats, as this plant is the only slaughterhouse that offers on line PSE monitoring. The PSE status is indicated on each carcass and forms part of the return faxed back to Murrellen Pork on the day of slaughter.

Carcasses accepted to have the Murrellen Pork Brand must comply with the specification stated in Part 3 of this manual and this differentiates the product, in terms of eating quality, from all other pork produced in New Zealand.

Carcasses that fail to meet the PSE standard are sold to a major pork supplier where they are boned and the affected meat routed into mince (where water holding capacity is not critical)

Where the carcass is branded as Murrellen Pork, the eating experience is guaranteed – with other pork it is a possibility. This is the key output of the Murrellen system – certainty for those clients who must provide succulent, tender pork as a keystone of their business.