大多数肉食者吃过腊肠、火腿、熏鲑鱼、烟肉、牛肉干或培根。所有这些食物都属于腌肉的范畴,但我们很少停下来思考腌肉意味着什么,以及它如何影响肉。腌肉健康吗?腌制肉类的具体步骤是什么?在家怎么做?有没有让人生病的风险?
Curing meat for the first time can feel intimidating. Intuitively, we understand that when we preserve meat there is a high risk of illness and spoilage. However, meat curing is an ancient practice that has been used safely for thousands of years. Around 150 B.C., Cato the Elder, a Roman noble and politician wrote:
This is the way to cure hams in jars or tubs. . . . Cover the bottom of the jar or tub with salt and put in a ham, skin down. Cover the whole with salt and put another ham on top, and cover this in the same manner. Be careful that meat does not touch meat. So proceed, and when you have packed all the hams, cover the top with salt so that no meat can be seen, and smooth it out even. When the hams have been in salt five days, take them all out with the salt and repack them, putting those which were on top at the bottom. . . .
After the twelfth dayremovethe hams, brush off the salt, and hang them for two days in the wind. On the third day wipe them off clean with a sponge and rub them with oil. Then hang them in smoke for two days, and on the third day rub them with a mixture of vinegar and oil.
Then hang them in the meat house, and neither moths nor worms will touch them.”(De Agricultura, 162)
At its simplest, all it takes to preserve meat issalt和时间。然而,有一种艺术和科学的腌肉,我们将在这篇文章中探讨。
Curing meat just refers to preservation. There are two very distinct types of cures with different processes and outcomes – a salt cure, which Cato the Elder describes, and a microbial cure or fermentation cure.
Salt Cures
Salt curing preserves meat by dehydrating the cells of the tissue. Osmosis draws water out of the meat, and spoilage microbes can’t live without it.
Typically, salt is mixed with sugar for a more palatable cure. The ratio varies depending on the recipe, type of meat, and length of cure, and this ratio is one of the components in the flavor outcome. The curing mixture can be applied using a brine or directly to the surface of the meat.
这一过程主要使用非碘化氯化钠,但通常还会添加一种臭名昭著的硝酸钠盐。它可以抑制肉毒杆菌(一种特别危险的腐败微生物)的生长,但最近它被认为是潜在的致癌物。在《食品安全》中有更多关于硝酸盐安全使用的讨论。
You can salt cure by either applying salt directly to the surface of the meat or by immersing the meat in a brine. Salting the surface draws water out of the meat, and this liquid needs to be regularly poured off the meat and the salt mix reapplied.
Brines allow deeper penetration of the salt and produce a saltier tasting product, often requiring the salt to be soaked out before cooking. Not all meat that is brined for flavor before cooking would be considered cured. For example, grocery store rotisserie chickens are not cured, although they have been brined. The preservative effect is the key to curing.
Nitrate-Free Currant Bacon
Ingredients
- 1 slab fresh pork belly
- 1 pound salt
- 1 pound sugar
- Handful of dried currants
Directions
- Mix the salt and sugar in equal proportions with the currants and set aside.
- Put the pork belly in a shallow tray, like aPyrex dish, and sprinkle the curing mixture liberally on all sides, rubbing it in with your hands if desired. Don’t use the full 2 pounds of salt and sugar at once.
- Cover the dish and put in the refrigerator; set aside the rest of the curing mixture. Water will be pulled out of the meat.
- Twice a day for 2-3 days, empty the water and repeat salting the surface of the meat, until over the course of 12 hours, little to no water is drawn from the meat.
- Once the salting is finished, dry the surface of the meat with a paper towel and smoke.
You can stop salting the meat at any point if you plan to preserve it with freezing and refrigeration. Store-bought bacon is not shelf-stable because it has been insufficiently salted.
However, for a fully cured product, continue salting until water no longer leaves the meat. This product will be unpalatably salty but safely preserved, and for best eating, cut into small bits in a soup or other dish.
Another tool to help safely preserve meat is the use of sodium nitrate, orpink curing salt. This allows you to use less salt overall and still have a safe product. Always follow the instructions on the packaging when using nitrate salt.
Microbial Or Fermentation Cures
Before we dive into microbial cures, I want to provide you with a quick glossary so we’re all on the same page.
A Quick Glossary:
- Anaerobic: environments without oxygen
- Dry cure: another name for fermentation cures
- Beneficial microbes: Any non-toxic microbe that causes a desirable result when introduced to food
- Fermentation: digestion of sugars in the absence of oxygen into acids and alcohols
- Inoculate: the introduction of beneficial microbes to the substrate
- Pathogens: harmful microbes which cause illness in humans when consumed
- Substrate: the food or material that microbial processes are happening to
The far more complicated and delicate art of curing is fermentation. Curing meat with fermentation is exactly the same process by which any other fermented food, like sauerkraut, yogurt, kimchi, sourdough, kombucha, and wine are produced. Fermentation is the practice of introducing microbes, which are not toxic to humans, that eat sugars and sometimes proteins in the substrate.
As beneficial microbes digest the sugars in an anaerobic environment, they produce acid or alcohol, as well as carbon dioxide. Acid and alcohol are both preservatives, and when done correctly, the growth of beneficial microbes introduces enough of those substances quickly enough to prevent the growth of pathogens. Fermentation is also a process of developing a desirable sour or tangy flavor.
Preparing meat for fermentation involves salt, but not enough to inhibit the growth of all organisms. For greater safety, use curing salt with nitrates, following the instructions on the packet. Most meat fermentations involve inoculation but not all.
For fermented sausages like salumi, keep in mind that sanitation and food safety will be of the utmost importance, far more so than in making cooked sausages.
Once the meat is prepared, it must be aged in a curing chamber while the fermentation progresses. A curing chamber, like a cheese cave, is a dark, sterile environment or one inoculated with beneficial microbes, with the correct temperature and humidity to encourage the desired microbial processes while inhibiting as many harmful microbes as possible. An improvised curing chamber can be made with a mini-fridge, as long as it is modified with atemperature and humidity sensor.
根据配方和最终产品的不同,发酵可能需要几天、几周或一年以上的时间。这些肉应该定期检查。一些食谱和微生物会导致表面霉菌在肉上生长,尤其是在发酵香肠(如腊肠)的肠衣上。
Always inspect the mold for uniformity and for any other colors and textures. An unpleasant or rotting smell is always an indicator of spoilage, and the meat should be removed from the chamber immediately. One part of your batch spoiling may not instantly mean the rest is inedible, but it is a warning sign that something about your recipe or your environment was not correct.
发酵是一个复杂而微妙的过程,对许多人来说,这是一门需要终生掌握的艺术。有些发酵比其他的更容易获得和容易,但肉不是其中之一。这并不是要打击你的信心,但要安全地发酵肉类,需要了解比这里描述的更详细的微生物过程和风险。
Start with a book, like the “Art of Fermentation” by Sandor Katz, which is intended to guide beginners through each step of the fermentation process. As always, the best way to learn is to find a mentor or friend to work with.
Flavor
决定一道菜好坏的最重要因素是肉的好坏、饲养方式以及吃什么。最好、最健康、最美味的菜肴都是用好肉做的。
Fats from animals raised outdoors and on pastures havehigher levelsof antioxidants, omega-3s, andfat-soluble vitamins like A and E.Any type of meat can be smoked. No matter what your ingredients are, the quality of your sourcing will raise the quality of your final product.
Another important factor in flavor is salt to sugar ratios. Sugar is not an essential part of the curing process in that it doesn’t help preserve the meat at all, but it cuts the saltiness. Home-salting meat is an experiment in balance and personal taste. While recipes can help you get the ratio of salt to sugar to meat correct, I’ve found it nearly impossible to predict the saltiness of the final product without a test batch.
You can always err on the side of less salt and plan to refrigerate or freeze the product. All cured meat products you buy at the grocery store do not actually have high enough levels of salt to be shelf-stable.
Historically speaking, salted meat would often be soaked in water and rinsed before cooking. It was not expected to be edible straight out of storage. When you do want to take the leap for the first time to make a shelf-stable cure, make a small batch and expect it to be very salty.
Additional spices and ingredients can be added to cures for nuance in flavor, like honey, pepper, thyme, marjoram, or even dried fruit like currants. However, these flavors will all be overwhelmed by too much salt, so the salt to sugar balance is paramount.
In fermentation, part of the flavor comes from the beneficial microbes themselves. Fermentations are a delicate and sophisticated balance of a number of microbes, and it is rare for a fermentation process to involve just one.
微生物活动的混合是如此的精确和无限的变化,它创造了布里干酪和卡门贝尔,埃芒尔和格鲁耶尔之间的差异,或香槟的味道,独特的法国香槟。
每个制作酸面包的烘焙坊都有不同的既定文化,这就造成了面包味道的巨大变化,尽管配料——盐、水和面粉——是相同的。肉类也是如此。只有时间、经验、实验,以及微生物群体的反复无常,才能改变发酵的味道。
Food Safety
With cured meats, spoilage and disease are large concerns. Some of the usual food safety requirements do not apply since curing is a preservation method meant to allow meats to be stored at room temperature. However, when not trying to establish a microbial community, curing meat should happen under refrigerated conditions.
当腌制充分并脱水后,肉类应储存在阴凉干燥的地方,避免阳光照射,以达到最佳保存效果。随着时间的推移,肉的味道会变得不新鲜或氧化,但变质的肉会有一种明显可怕的气味。
In addition to spoilage, there are a couple of particular diseases, botulism and listeria, that are of great concern to charcuteries. Those microbes do not cause a smell or visual change. The only way to detect them is to test for them, but strict control of the curing process can prevent these illnesses.
Botulism
Botulismis a foodborne illness that is often fatal. It is caused by a microbe,clostridium botulinum,that lives commonly in soil, but it is not the microbe itself which is harmful, rather a neurotoxin that it produces. Botulism only produces a toxin in anaerobic environments – where there is no oxygen, like inside the tissue of curing meat.
Since this takes some time, it poses no danger on fresh meat and vegetables. Heating to cooking temperatures kills active microbes and denatures dangerous toxins, but the microbe uses protective spores which are not damaged at cooking temperatures (140 degrees F). So even cured meat that has been cooked can develop botulism later.
There are three reliable methods to prevent botulism. First is salting and dehydrating, which prevents the spores from becoming active microbes and producing toxins. Second is low pH, or acidic conditions in recipes like pickled herring, where the acid inhibits microbial growth.
Last is pressure-canning, which heats the canned food, like tuna, to temperatures above boiling, where even the spores cannot survive. Since cured meats are often consumed without any of these methods (remember that the “cured” deli meat you buy in the refrigerated section is not actually fully preserved), the use of sodium nitrate in curing meat is very important for preventing botulism.
Listeria
Listeriais a bacteria which causes sepsis and other complications, especially in pregnant women, infants, and the elderly. It is a common worry in any raw product, like fermented meat, raw seafood, and raw milk and dairy products.
Unlike botulism, the listeria bacterium also occurs on fresh fruits and vegetables, and it is one of the few organisms that can continue to be active in a refrigerator below 41 degrees Fahrenheit. The temperature needs to be below 39 degrees, a small but crucial difference, to inhibit listeria growth.
However, since it is a live organism, instead of a toxin, it can be controlled and killed with the same methods of sterilization used to prevent any contamination – heat, salt, acid, alcohol, or another disinfectant. Cleanliness of your work space is paramount in preventing listeria.
肉毒杆菌中毒、李斯特菌和其他食物传播微生物的最大风险是发酵肉类。如果良好的微生物培养不能正确建立,并迅速产生酸和醇,有害微生物就会繁殖。Fermentation cures do use some salt, and most safe, reliable recipes include nitrates also, which inhibits肉毒梭状芽胞杆菌。
The American and industrial approach to controlling listeria is absolute sanitization of all surfaces. Curing rooms, creameries, and other places where fermentation take place are quarantined from outside microbes and intensively cleaned. The historic and European approach to bacterial control is to rely on the established populations of good or desirable microbes to outcompete disease-causing bacteria.
Cheese caves, charcuterie curing chambers, creameries, and other places where food is fermented, have ancient and established populations of beneficial microbes which prevent listeria and botulism for taking hold and also provide a unique flavor to the product.
无论你使用什么预防方法,在发酵肉类时,检测有害微生物总是很重要的。任何做烹饪或农业测试的实验室都可以测试你的成品是否有李斯特菌和肉毒杆菌中毒。USDA standards also call for facility inspections, anew requirement since 2002, which has caused tighter standards of cleanliness. Since listeria, in particular, is a common environmental bacteria, sometimes facility testing comes back positive even if the fermented product tests negative.
Nitrates
Sodium nitrate is a naturally occurring salt which gives a pink color to cured meat, the classic ham color and helps prevent the development of botulism microbes. Nitrates are an important component of protein molecules and naturally occur in vegetables and fruits. In fact,80% of all dietary consumption of nitratescomes from eating vegetables.Celery saltis used as a substitute in meats cured “without nitrates,” but those recipes actually include a higher level of nitrates than recipes using curing salt.
Curing salt is a mixture of sodium chloride, with about 6-10% of sodium nitrate or nitrite. Nitrates and nitrites are similar except in the number of oxygen atoms in the molecule and react chemically in the same ways. Curing salt is pink in color, not to be confused with Himalayan pink salt. Historically, saltpetre has been used in curing as a source of nitrates.
In recent years, nitrates have come under suspicion for their relationship to a compound callednitrosamines,这在一定程度上是致癌的。当硝酸盐或亚硝酸盐与较长的氨基链结合时,会产生亚硝胺。This reaction occurs inhigh heat or high acid environments, including the acid of the stomach. Frying cured meats, like bacon, poses a higher risk of creating nitrosamines, although some occur in the digestive process regardless of cooking method.
However, in small quantities, the risk of nitrosamines causing damage is low, and nitrates are an important safety measure for meat fermentation, especially for beginners. In ferments, the compounds pose lower risk of becoming carcinogenic because the meat is not heated to high temperatures before eating.
Another health concern about cured meat is the high levels of sugar and salt. For people needing a low-sodium or low-glucose diet, cured meats are not as safe or healthy as fresh meat. For most people, however, in moderation and especially when made with high-quality meat to begin with, cured meat is a healthy and delicious option.
Curing meat ranges from the simple to the overwhelmingly complex, but the good news is there are easy places to start, and we live in a day and age where our lives do not depend on successfully curing meat to be shelf-stable.
When in doubt, always use the refrigerator or freeze method for your product, and don’t be afraid to throw meat away if you are afraid it is spoiling. If you take common-sense precautions for food safety and aren’t worried about having a very salty first try, there isn’t much to be worried about for taking your first steps toward home-curing meat.
Horstsays
Great treatise on preserving meat!