Is that pork on your plate really white meat?

It’s the season for eating white meat: chicken and fish have been flying off the supermarket shelves over the past couple of days. And in recent decades pork has also been marketed as the “other white meat”.

The pork industry has been promoting it as an alternative to chicken for families looking for a cheap, low-fat, and nutritious form of protein. But is pork actually a white meat and what is the difference between red and white meats?

We’ve been chewing on this a fair bit lately, as one of the biggest differences we’ve noticed about our free range Wessex saddleback pork is the colour of the meat – it’s a lot darker (and that’s apart from the extra flavour and juiciness). It’s particularly noticeable with the meat found in the legs and shoulders.

Wessex Saddleback pork shoulder cross section

So why is meat light or dark? It all comes down to two different types of muscles: slow-twitch and fast-twitch. Animals will have different coloured meat depending on what type of muscles they use and their ratio of slow to fast-twitch muscles.

The slow ones are used often, for extended activities like constant walking, standing or flying. They’re the muscles found in the shoulders of pigs or the thighs and legs of chickens. Slow-twitch muscles are slower to contract, good for endurance, and are the muscles needed to help a marathon runner go the distance.

They need a lot of fuel and they get this through the protein myoglobin, which stores large amounts of oxygen to support the long-term energy use. Myoglobin is a reddish colour, sort of like hemoglobin in blood, which is why slow-twitch muscles are dark. They’re also linked with more fat or marbling, as fat has to be kept close-by for the constant demand for fuel.

In general, the more exercise a muscle gets, and the older the animal, the greater the need for myoglobin, and so the meat’s darker. Slow-twitch muscles, or red meat, tend to hold moisture better, have more fat, and hence are more flavoursome and forgiving to cook.

Fast-twitch muscles are used for sudden bursts of quick movement – like the breast of a chicken to help it escape from a predator. They have smaller amounts of myoglobin and instead need glycogen for their energy. They’re the muscle fibre types that a sprinter develops.

Fast-twitch muscles, or white meat, tend to carry less fat and while they can be tender if cooked properly they tend to be dry and bland and lack the flavour of slow-twitch muscles.

This explains why the working joints of free range pigs are not only darker in colour but also have more flavour, because of the marbling. An intensive pig that lazes about and is processed at a much younger age will have less slow-twitch muscles and its meat won’t be as dark and when cooked it is usually dry and lacks flavour.

Over the years meat breeders have been selecting animals that grow fast, and so they’ve got more fast-twitch muscles – making the meat leaner and whiter. This is what’s happened in the pork industry, because of its desire to sell itself as the “other white meat”.

The real casualty has been the loss of breeds with a higher ratio of slow-twitch muscles. Fortunately we’ve still got some old breeds like the Wessex Saddleback that haven’t been influenced by modern genetics and the push for fast, lean growth. They have the unique property of a lot of slow-twitch muscles, marbling, and best of all, moisture and flavour.

So if you’re having white meat this Easter, you’d better stick to your fish or chicken breast, or, the loin of an intensive farmed white pig!