In its simplest form the word ‘curing’ means ‘saving’ or ‘preserving’ meat and the definition covers preservation processes such as: drying, salting and smoking. When applied to home made meat products, the term ‘curing’ usually means ‘preserved with salt and nitrite.’ When this term is applied to products made commercially it will mean that meats are prepared with salt, nitrite, ascorbates, erythorbates and dozens more chemicals that are pumped into the meat. Meat cured only with salt, will have a better flavor but will also develop an objectionable dark color. Factors that influence curing:
- The size of the meat - the larger meat the longer curing time.
- Temperature - higher temperature, faster curing.
- Moisture content of the meat.
- Salt concentration of dry mixture or wet curing solution-higher salt concentration, faster curing.
- Amount of fat-more fat in meat, slower curing.
- pH - a measure of the acid or alkaline level of the meat. (Lower pH-faster curing).
- The amount of Nitrate and reducing bacteria present in the meat.
The curing temperature should be between 36-40° F (2-5° C) which falls within the range of a common refrigerator. Lower than 36° F (2° C) temperature may slow down the curing process or even halt it. Commercial producers can cure at lower temperatures because they add chemicals for that purpose. There is a temperature that can not be crossed when curing and this is when meat freezes at about 28° F (-2° C). Higher than normal temperatures speed up the curing process but increase the possibility of spoilage. This is a balancing act where we walk a line between the cure and the bacteria that want to spoil meat. The temperature of 50° F (10° C) is the point that separates two forces: below that temperature we keep bacteria in check, above 50° F (10° C) bacteria forces win and start spoiling the meat.
Meats were traditionally cured with Nitrate. Before Nitrate can release nitrite (the real curing agent) it has to react with bacteria that have to be present in the meat. Putting Nitrate into a refrigerator kept solution (below 40° F) will inhibit the development of bacteria and they may not be able to react with Nitrate. On the other hand sodium nitrite works well at refrigerator temperatures. When used with Nitrates/nitrites, salt is an incredibly effective preserving combination. There has not been even one documented incident of food poisoning of a meat cured with salt and Nitrates.
People in the Far East, Africa, South America and even Europe are still curing meats at higher than normal temperatures without getting sick. That does not mean that we recommend it, but if someone in Canada shoots a 1600 lbs (726 kg) Moose or a 1700 lbs (780 kg) Kodiak Bear he has to do something with all this meat. He is not going to spend 5,000 dollars on a walk-in cooler, is he? These are exceptional cases when curing can be performed at higher temperatures. After the Second World War, ended most people in Europe neither had refrigerators nor meat thermometers, but were curing meats with Nitrate and making hams and sausages all the same.
Because of primitive conditions the curing temperatures were often higher than those recommended today but any growth of C. botulinum bacteria was prevented by the use of salt and Nitrates.
They also predominantly used potassium Nitrate which works best at temperatures of 46-50° F (8-10° C) and those were the temperatures of basement cellars. There was not much concern about longer shelf life as the product was consumed as fast as it was made. Salt and nitrite will stop Cl. botulinum spores from developing into toxins, even at those higher curing temperatures. Due to increased bacteria growth at those higher curing temperatures the shelf life of a product would be decreased. Remember when handling meats, the lower the temperatures the slower the growth of bacteria and
the longer life of the product. Extending the shelf life of the product is crucial for commercial meat plants as the product can stay on the shelf longer and has better chances of being sold. Curing is a more complicated process than salting. In addition to physical reactions like diffusion and water binding, we have additional complex chemical and biochemical reactions that influence the flavor and color of the meat.
What Will Happen if Too Little or Too Much Cure is Added?
With not enough cure, the color might suffer with some loss of cured flavor too. FSIS regulations dictate the maximum allowed nitrite limits and there are no limits for the lower levels. It has been accepted that a minimum of 40-50 ppm of nitrite is needed for any meaningful curing. Too much cure will not be absorbed by the meat and will be eaten by a consumer.
What Will Happen if the Curing Time is Shorter or Longer?
If the curing time is too short, some areas of meat (inside or under heavy layers of fat) will exhibit an uneven color which might be noticeable when slicing a large piece of meat. It will not show in sausages which are filled with ground meat, although the color may be weaker. If curing time is longer by a few days, nothing will happen providing the cured meat is held under refrigeration. You don’t want to cure bone-in meats longer than 30-45 days as they may develop bone sour even when kept at low temperatures. Taste your meats at the end of curing. You can always cure them longer in a heavier brine (to increase salt content) or soak them in cold water (to lower salt content).
Cured Meat Color
Fresh Meat Color
The color of fresh raw meat is determined largely by the amount of myoglobin a particular animal carries. Meat color is determined largely by the amount of myoglobin (protein) a particular animal carries. The more myoglobin the darker the meat, that simple. The amount of myoglobin present in meat increases with the age of the animal. This color is pretty much fixed and there is not much we can do about it unless we mix different meats together.
Different parts of the same animal, take the turkey for example, will display a different color of meat. To some extent oxygen use can be related to the animal’s general level of activity; muscles that are exercised frequently such as the legs need more oxygen. Muscles that are exercised frequently such as legs need more oxygen. As a result they develop more myoglobin and a darker color unlike the breast which is white due to little exercise.
Pork loin is light pink in color as this muscle does not work much, however, leg muscles excercise a lot and are light red. Heart of any animal is dark red as it works continuously.
Fish float in water and need less muscle energy to support their skeletons. Most fish meat is white, with some red meat around the fins, tail, and the more active parts of the fish which are used for swimming. Most fish don’t have myoglobin at all. There are some antarctic cold water fish that have myoglobin, but it is confined to the hearts only (flesh of the fish remains white but the heart is of a rosy color). As most of the fish don’t have myoglobin the meat is not going to be pink and that explains why very few fish recipes include cure.
The red color of some fish, such as salmon and trout, is due to astaxanthin, a naturally occurring pigment in the crustaceans they eat. Most salmon we buy is farm raised and as it is fed a prepared commercial diet that even includes antibiotics, its meat is anything but pink. The only reason that farmed raised salmon flesh is pink is that canthaxanthin (colorant) is added to the food the fish eats.