Lovely image provided by blood–stock.

Heated discussions, desperate queries, massive brain-imploding confusion about blood safety pop up quite regularly in sang friendly spaces. Unfortunately, while there are some excellent, albeit brief mentions out there regarding the topic, nothing really attempts to do more than vaguely address the subject. Information is divided, curtailed, and often painful to follow through various spaces and mediums. In forums & channels, for example, guidance can be wildly mixed in accuracy, even intention. There’s a lot of improper advice given that, if put into practice, could possibly make people ill. The bottom line is this: if you’re a sang, you’re likely ingesting blood; not only that, but in a raw state. When it comes to health and safety, I had hoped that sound attempts at reducing the risk of potential pathogens would be kept alongside proper food management techniques. They are not.

In this article, I will be focusing on information regarding the safety of handling blood that has already been collected from a source and treated. Due to the degree of pertinence, therefore, animal blood will be used as the prime example here. If you’re collecting the blood yourself and it has not been treated, here is an amazing article detailing the process. If you’re more curious about human blood, you may look here or there to start. Consuming raw blood comes with inherent risks that are made more complicated with mishandling. Difficulties in sourcing blood to begin with can also pose a problem. The ease of obtaining animal blood and its quality depend greatly on your location, unfortunately – or fortunately, if you’re a lucky bastard. In areas where people are not far removed from their food sources, blood is much easier to obtain. Lack of demand and cultural aversion in other places can make acquisition quite difficult. It’s worth noting that animal blood is illegal in some countries, so save yourself the added grief by doing some research on the subject before beginning your fervent quest.

It’s thirsty-time and you have no donor? Don’t waste time weeping. Animal blood is a good option for sangs in need who are going through a difficult dry spell. Butcher shops will often carry frozen pig’s blood (sometimes beef) of decent quality. If not typically stocked, many of them can make a direct order for you without any additional charges. Asian markets can be a sang’s friend for both cow and pig’s blood (and they won’t bat an eyelash at you). Quality can, admittedly, vary greatly, however.. Farmers markets and direct contact with private livestock handlers can be ideal options. Don’t be coy about it. It may be unfashionable at the moment, but cooking with blood isn’t unheard of, especially in these circles. If you’re reluctant about it, you can take a recipe with you to help temper the situation. Another option for those without access to such is our old friend, the internet. Even Facebook has groups dedicated to getting in touch with farmers. For the shy, overly secretive sang out there, or the one that’s just SOL, many online meat stores will ship frozen blood (for an added price, of course). Again, quality can be extremely hit or miss here, sadly.. horribly.. painfully.. furiously.. mind numbingly.. Anyhow, there will be a lot of trial and error happening, but don’t be discouraged! Keep your eyes peeled for opportunities and you will find them.

For the general population, blood is typically an off-putting, even frightening substance. Waat?! As sangs, we may scoff at such nonsense; however, when scientific evidence is considered, it’s not entirely without reason. Being packed with protein and other nutrients, it’s no surprise that blood is a highly corruptible substance. When it becomes tainted, it’s the stuff of nightmares. Blood Gone Bad. It’s an excellent gateway to a variety of unpleasant, sometimes deadly beasties. This holds true for all blood, human & animal alike. Several pathogens often make the jump from animal to human through zoonotic transmission. Sounds like creepy mind violation, doesn’t it? Well, some of it actually is..;) The more recognizable of these organisms are trichinosis (pork especially), avian flu (poultry, water and wild fowl), rabies (mammals, wild game primarily), tuberculosis (mammals, cattle in particular), salmonella (common in poultry and cattle), botulism (water fowl), Lyme disease (primarily rodents, hares, birds, and contact with deer ticks), Streptococcus suis (pork again), and prion diseases (yes, mad cow disease, folks). Many of these pathogens are not blood-borne, however, poor butchering and handling practices can lead to infection and/or contamination.

Have I terrified you yet? Please don’t be afraid or dismayed. That’s not the purpose of this article and I’m not trying to spoil your dinner. There is good news, at least in many countries. Infection is much less common due to aggressive disease prevention strategies, and the adoption of strict rules regarding the slaughtering and processing of livestock in commercial facilities. In the U.S., animals brought to official abattoirs are inspected both prior to and after slaughter for visible signs of health, as well as potential disease and other problems. Their carcasses must pass through several rigorous safety checks before being allowed to enter the public food supply. Blood, itself, is required to be processed immediately at time of slaughter, using sterile instruments and often closed containers. At least that’s the supposed official protocol. When it comes to food safety, general industry consensus always assumes that the consumer will be cooking the animal products, so these preemptive safety practices only extend so far. Freezing, salting, or acidifying blood is no guarantee of safety either. There’s no absolute way around the intrinsic risks of consuming blood, however, there are ways to minimize them. How far you decide to go with that is up to you and what you’re comfortable with.

  

There are a few things that I look for when purchasing raw blood. Smell.. If it smells bad, don’t consume it, especially not raw. While fresh blood can have a strong scent, especially with certain animals, an off smell is likely an indication of decomposition and possible contamination. Coloration is also an important factor and can tell a great deal about the sordid life your blood has lived from slaughter house to that cozy store freezer. Though the depth of color in blood can vary by animal, darker colors can indicate oxidization, which naturally happens as blood ages (or is mishandled). Look at the top of the container. Is the blood bright or is it dull? Steer clear of any packaging that’s suspicious or damaged. Check the date. Even if it’s frozen. As blood ages, it picks up foreign smells and scents. It may also have developed a sad case of freezer burn. Unless you know directly where the blood has come from and what its been through along the way, I’d recommend a no date, no buy policy.

So now you have that lovely container of blood. What to do? Well, unfortunately, without proper medical grade preservatives and completely sterile collection methods, blood stored in the fridge is only briefly less temperamental. Even with common preservative methods employed for food-bound animal blood, such as the addition of sodium citrate, the shelf life of Our Precious is a considerably sad and short one. Bad news, folks: blood should either be consumed in entirety, or processed within a day of acquiring / thawing by cooking or one final freezing. Keep in mind that freezing blood more than once is not encouraged, as it has most likely been frozen already for transport. Rupturing of the cell structure, or haemolysis, happens naturally as ice crystals form in the blood during the freezing process. Doing this several times will lead to a gloopy, watery, possibly contaminated hot mess that is as unappetizing as it is ineffective.

How does one prevent this this sort of thing from happening? Well, planning ahead, working quickly, and having the proper containers and storage methods are good places to start. I find it best when thinking about storing blood to pay great attention to the actual amount you need on a typical basis and portion accordingly. You can easily create servings of blood using ice trays to freeze neatly and then pack into airtight containers for later use. How long does that frozen blood last? Personally, I wouldn’t keep it for much longer than a month because blood has an uncanny fondness for absorbing terrible odors and wayward flavors in a surprisingly efficient manner. Why would you want to keep it that long anyway?

Before you begin the whole bloody process, it’s very important to handle it with care. Get it home and in the fridge quickly. If you receive it frozen, it’s best to keep it that way until you’re ready to process it completely. Thawing your blood in the fridge is the safest route, but keep in mind that, depending on the temperature of your fridge and its location within, it can actually take several days. If you’re struggling and need to thaw it more quickly, place the frozen, packaged blood on a clean container (plate, shallow bowl, etc.) in a sanitized sink. Use a steady stream of cold water to help initiate and complete the melting. Not hot water. Not warm water. Not a sink full of water. Running cold water. I know it’s difficult, often painful to wait. You can pour it off as it thaws, just try to be careful not to contaminate in the process (i.e., don’t drink out of the container;).

In the meantime, you can sanitize your equipment for the freezing. The dishwasher works well for this and no other chemicals need be involved, aside from soap, of course. Wash your hands! Clean and sanitize your work space. Beware the floaters.. Even frozen blood will likely be a clotted mass upon thawing. I recommend using a blender to help destroy some of the fibrin. At this stage, unless the blood is going to be used for cooking purposes, I sometimes use a small amount of filler liquid to help with the liquefaction. Coconut water is great for this because it doesn’t really interfere with the flavor of the blood in a noticeable way. You can choose to keep or remove the foam from the agitation (it doesn’t bother me personally). Pouring the blood through a fine mesh strainer or cloth will help remove smaller solid bits and preserve future palatability. Use something like a measuring cup with a lipped spout to portion blood into the tray and then go directly into the freezer with it. Ice cube trays with lids, like this one, are wonderful. Though not air tight, they do help with reducing contaminants. The silicone also makes it much easier to remove the blood. I recommend putting the cubes into air tight, freezable containers. Blood kept like this can be thawed and consumed quickly, which is always optimal.

Note: Blood may separate after thawing. It happens naturally, even with blood that’s never been frozen. You may still find floaty bits. It may be semi-gelatinous again. As long as you’ve handled the blood properly, it’s likely just more clotting, not an indication bacterial growth. Blood does what it wants! ¯\_(ツ)_/¯

More technical approaches and musings:

Freezing does not kill all potential pathogens. Some are quite resistant to low temperatures and can survive this process far longer than I would recommend keeping blood to begin with. If you’d like to experiment with quality control, this is an interesting article on using glucose for long term blood storage.

I’ve heard of people using milk filtration techniques for blood. While an interesting concept that could likely increase the safety of blood by removing some of the bacterial load, filtration success is dependent upon certain factors such as pore size, type of filter, and even the equipment being used. It is not effective at removing all contaminates that might exist within milk and certainly not blood.

Thermal processes such as pasteurization come up, as well. Blood is notoriously difficult when it comes to rising temperatures. When researching the best temperature for blood pasteurization, a common number I found was 60°C (140°F). How long is necessary? That varies by each potential pathogen, unfortunately, so it’s hard to say. Some sources say thirty minutes, but I’ve seen up to 10 hours in one study. To be able to attempt such a feat, you’d likely need something like a sous vide immersion circulator. Unfortunately, blood is such a difficult thing to heat, unless your aim is to actually cook the blood outright, using a low temperature / long time approach is probably the best option. Keep in mind that blood begins to denature at about 45 °C (113 °F) and completely after about 70 °C (158 °F). Blood that has been heated in any way may be changed.

Sources and further reading:

Techniques and hygiene practices in slaughtering and meat handling
Slaughter Inspection 101
Ante-Mortem Inspection
Slaughterhouse Animal Blood Collection and Separation
Physical And Rheological Properties Of Slaughterhouse Swine Blood And Components
Animal slaughter
Cold Preservation Of Meat Products
Perishable Foods
Sodium Citrate Uses In Blood Collection
Advice On Eating Game
Protect Yourself from Brucellosis
Trichinae Survival
Trichinosis
Trichinellosis
The Mystery of Kuru
Prions and Prion disease
Salmonella infections in poultry: Diagnosis and control
Lyme Disease
Streptococcus suis : An Emerging Human Pathogen
Zoonotic Diseases
Psychrotrophic Bacteria