A Personal Note
Often many customers will report to us, "it was delicious", after trying some of the premium meat we sell at Ruxstons. But why do I also hear this very same statement when people will have tried meat from animals that most probably will have been raised indoors and badly. Such as beef in burgers involved in some of the fast food giants including Burger King, are they both really equally delicious? So, for the purpose of this study, removing the other factors we value in meat production, such as high welfare, the environment, and the diet. Can the quality be measured, and do animals genuinely raised outdoors produce better meat?
For myself, trying known poorer quality beef vs known "well raised" beef, I noticed, that even amongst the good quality, the most tender were the ones that had been outside until the end. Beef that is consistently tender all year round from outwintered cattle. Similar with pork where pigs that were raised outdoors up until slaughter. With colour and tenderness substantially different to what you can find in a supermarket, where there is pork on sale from pigs that may have never seen the light of day.
Summary
Using cattle as the main part of this research, I theorise that animals raised outdoors under regular sunlight, will have an increased likelihood of actually producing a more tender meat, and an explanation, not a placebo, as to why outdoor bred and raised animals do in fact create a better quality meat, that will likely be ranked more highly among consumers. [3][8]
While flavour of the fat is a factor, it's excluded here, as there is too much matter of opinion involved of what makes one meat product over another taste better among the most premium choice.
Flavour of fat is majorly influenced on diet. Grain fed vs 100% grass fed animals will have different flavours and some of the population will prefer one over the other, without finding the taste of either meat offensive.
Aside from flavour, tenderness and the texture can be more distinguished in quality, as a more tender final meat product is likely to be voted better quality than a chewy and tough meat product.
Farmed animals that live naturally outdoors are exposed to UV light from the sun. As with humans, this causes the body to produce Vitamin D3, which plays a role in increasing the ability of calcium absorption from our diet in the gut, which in turn, elevates the calcium levels present in the blood.
The high calcium levels are important in its relevance to tenderness, and thus quality, as after slaughter, these higher calcium levels, allow calcium-dependant enzymes that exist in the muscles, known as calpains, to tenderise the meat.
Low levels of calcium in the blood can indicate an animal carcass could have been deprived of natural sunlight during the end of its life and will not be able to reach its full potential of tenderisation, ultimately creating a lower quality, more tough meat and therefore considered "lower quality" by the general population.
On the other hand, an outdoor raised animal with enough sunlight per day over a certain threshold, is able to absorb more calcium into the bloodstream and the carcass will be more likely to tenderise faster, and to a higher extent, producing higher quality meat.
Additionally this tells us UK Farmers growing animals outside are likely to be producing better quality produce which would be deserving of better prices paid by supermarkets. With increased development of ways of tenderness scoring with shear tests, using theory, and collecting statistics, we are able to predict the likelihood of the quality of meat before it is even tried. Alongside evidence that consumers are happy to pay extra for a known increase in quality, there is no excuse for unfair prices to be paid on much of the UKs outdoor, higher welfare meats.
Why "flavour" is difficult to measure within quality?
Amongst the UKs population, many people will say they like one flavour of meat over another, as an example with beef, grain fed and fully grass fed beef will produce different tastes due to the composition of fatty acids and antioxidants [1] and some may prefer one over another as shown in some surveys. [2]
However, flavour, is something of which the matter of opinion can cause a split so it is hard to judge what is, and what isn't better. Although, the tenderness of beef is rated as an important factor among consumers. It is highly unlikely anyone prefers to chew on tough beef even if the flavours were enjoyable, meaning tender beef is widely considered a better product overall, and the majority of people would prefer tender meat, and even pay a premium for it to be guaranteed. [3]
How exactly could UV light from the sun improve meat tenderness?
A possibility of happier outdoor raised animals tasting better, is that the tenderness of beef could be increased from naturally raised animals that live outdoors, due to exposure to natural ultraviolet light from the sun, on animals' skin to produce vitamin D3.
Animals such as pigs will absorb the ultraviolet radiation through the skin, and cattle will through exposed areas such as the nose, eyelids, ears, lower flank, but even also throughout all hair covered areas.[4][5][6]
Vitamin D3 (Cholecalciferol) produced at the skin when exposed to UV light, goes through a multi-step process through the liver, and then the kidney to become calcitriol, which is then active in the digestive system of many animals, entering cells such as enterocytes, an intestinal absorptive cell.
Calcitriol when in an enterocyte, binds to a protein known as a Vitamin D receptor, moves into the nucleus, finally activating a genetic program which increases the number of calcium (Ca2+) transporters in the enterocyte cell.
This, will allow more Ca2+ to be absorbed from the diet of an animal in the intestine. The Ca2+ pump also increases its activity, moving calcium out of the enterocyte and into the bloodstream on the other side, therefore finally creating higher levels of Ca2+ in the blood.
After slaughter, during the ageing process, the presence of Ca2+ allow calcium activated enzymes, μ-calpain and m-calpain, to tenderise the meat via their intracellular protease role, a digestion of sorts that partially breaks down the meat [8][9], making it more tender and palatable to the consumer. It is found that the higher the Ca2+ concentrations are, the more tender the beef is.
These propositions would suggest:
1) Meat from outdoor raised animals will be of better quality as it is more tender and an enjoyable eating experience
2) Outwintered farmed animals would show the most consistency year round, with winter having enough average daily sunlight to keep Vitamin D3 production at it's most optimum. (approximately 1.5 hours per day) [10]
3) Long hanging times, a method that is used to increase tenderisation, would become less meaningful in optimising the most tender beef. Ie. 28 days offers no noticeable difference over 21 days. Therefore, environmental benefits as less aging, refrigeration is required.
4) Outdoor raised animals, such as pigs, chickens, sheep and cattle could all show a positive effect on tenderisation in combination with at least a short hanging/aging period.
Vitamin D3 from the sun vs supplementation
From studies, it is seen that animals kept outdoors show higher levels of vitamin D3 [5]. However this gradually drops over 30 days if put indoors with no exposure to natural light, or under a threshold of about 90 minutes per day.[15] Calcium levels will then drop beyond this timing through lower absorption rates coupled with the natural excretion.
On the other hand, it is proved Vitamin D3 can be supplemented directly and give the same effect that an animal would get from the sun. And possibly higher levels of calcium ultimately.
However, in a study found that in lactating dairy cows, supplementation of Vitamin D3 was not necessary in summer time as the sunlight alone was sufficient.[12] Dairy cows, not used for meat typically, may be sometimes supplemented with Vitamin D3 as the excretion rate is three times as high, up to 30g a day from 10g[13]
Other factors in tenderness
As animals living outdoors could be shown here to have a positive effect on the final product, other major factors will also show and effect, such as long-term stress, and short term stress just before slaughter, and the genetics of the animals involved.
Outwintering isn't always an ideal option in many cases. Firstly, it can cause damage to the land, in some areas more than others which would eventually lead to poorer quality grazing or forage opportunity. In particular, many animals during poorer winter weather, can noticeably appreciate being indoors, naturally animals will seek shelter for protection of the elements. Most fields will not have an option for shelter during bad weather, and plentiful forage during good weather.
If animals get too cold and wet this can lead to stress, which would have a detrimental effect on the quality of the meat[11], not to mention the welfare.
The supplementation issue and its labelling...
As you may notice, if animals can be supplemented, and without clear labelling on, how do you know what is going to be better quality, and what may have been outside?
Animals with higher levels of vitamin D3 before slaughter produce darker meats. [14] Beef and lamb will be darker brown/red rather than light red, outdoor pork should be a more red pink than a pale pink.
And if they have been outside or supplemented? The diet should be visible in the product. Beef and lamb fat will display more yellow colouring due to the diet higher in grass. Pasture raised chicken which we sell has a golden yellow skin due to the high grass diet, all meaning that with access to natural pasture showing in the skin and fat, the animals will almost certainly have been outside.
The easiest way? Ask the retailer that is selling the meat. The traceability (or lack of) will give you all the answers you need to know, and in turn, asking and asking again, will create the demand that is desperately needed for more precise labelling of meat products.
Sources