Curing salt what it is and how much to use

What is curing salt?

Curing salt is an additive used in the production of cured foods. Its main function is preservation by inhibiting contamination by bacteria and fungi. One of the main reasons for its use is to suppress the proliferation of the bacteria clostridium botulinum, which contaminates food with botulinum toxin. In addition to preservation, curing salt also acts as an antioxidant and adds specific flavor and color to foods that use this additive. It is generally used in sausages, sausages or cured meats (smoked and/or dried). Curing salt is made up of a mixture of table salt, sodium nitrite and/or sodium nitrate. The curing salt acts on the meat, giving it the reddish color typical of cured products, such as salami, mortadella, sausages and sausages.

The characteristic red color of cooked cured meat products (that is, those containing nitrite or nitrate) is due to the pigment nitrosylhemochrome, which is the heat-denatured form of nitrosomyoglobin, which, in turn, is formed through reaction between nitric oxide (NO) from nitrite (NO₂) and natural myoglobin from meat. During cooking, the myoglobin (globin) protein chain denatures and separates from the heme group, thus producing the aforementioned nitrosylhemochrome, responsible for the characteristic red color of cured and cooked meat products.

The intensity of these reactions depends on some conditions, such as the presence and action of certain microorganisms, natural reducing agents in the meat (natural antioxidants/vitamins), mitochondrial enzymes, added antioxidants, pH of the medium, redox potential, type and form of packaging, oxygen pressure and conservation/storage time and temperature. There are many technical details, but in general there is a rule and proportion that can be used safely. It is not necessary to understand all the details, just the basics that we detail below.

The curing salts that follow the North American standard (instacure#1 and instacure#2) are composed of 93.75% of table salt (sodium chloride) and 6.25% of sodium nitrite (NaNO²). Some contain 4% sodium nitrate. Sodium nitrate (NaNO³) gradually loses an oxygen molecule during the curing process and starts to have the same composition as sodium nitrite, which is why it is used in longer curing processes, having a slower and more prolonged action.

To learn more about sodium nitrite and sodium nitrate, read Sodium nitrite and nitrate.

How much curing salt to use?

Each recipe usually calls for a different amount and this tends to create confusion when deciding how much curing salt to use. For this reason, the ideal is to standardize according to the limitations established by the competent bodies.

The calculations presented below were made based on the curing salt that follows the North American standard for the designation of Curing salt 1 or, as it is also known, Instacure#1, which contains 6.25% of sodium nitrite and 93.75% of common salt (Sodium Chloride). In Brazil there is no standardization, so it is important to check the quantity in the product purchased.

The Collegiate Board of the National Health Surveillance Agency, through RDC nº 272, of March 14, 2019, provides for food additives authorized for use in meat and meat products, determining that the level of residual nitrite and nitrate in the final product cannot exceed 0.015g per 100g of product, or 150ppm. Therefore, the added nitrite must be reduced during the curing process, ensuring that this limit is not reached in the ready-to-consume product. Following legislation, a maximum of 0.015g of residual sodium nitrite is limited for every 100g or ml of product (meat) or solution (brine). check out here the official table of additives and reference quantities.

The curing salt that follows the North American instacure#1 standard contains 6.25% of sodium nitrite, that is, 1g of curing salt contains 0.0625g of sodium nitrite. According to our calculations, the established residual limit is 2.4g of curing salt for every 1kg of meat\brine. In other words, this is the minimum to be added, because using this measure the final product will never have more than the maximum residual established as it is already at the limit and there is still a strong reduction during the curing process. Read the post Nitrite conversion time in cured meats where studies are presented on the reduction/conversion of nitrite in products.

The European Union limits it, as in Brazil, to a maximum of 150ppm, but there are exceptions such as Denmark, which limits it to 60ppm.

The North American FSIS (Food Safety and Inspection Service) differentiates between the types of nitrite insertion processes, such as injection, massaging and immersion. In the immersion and massage technique, a limit of 200ppm of sodium nitrite is established for the raw meat of the product to be cured. It is the equivalent of 0.02% of sodium nitrite. Converting we arrive at 0.2g of sodium nitrite for each kilo of meat. Calculating we arrive at 3.2g of curing salt for each kg of meat. Limit slightly higher than that established in Brazil. North American legislation still provides for a minimum to be added, which is 120ppm. In other words, as a safety measure, no cured meat product has additions below this limit.

It is well-founded scientifically that at least 50-75 ppm of nitrite are needed to maintain an adequate curing color in meat and to be able to inhibit lipid oxidation, as well as 75 to 100 ppm of nitrite are needed to contribute to the control of micro -pathogens and decomposition organisms.

We reiterate that the calculated values refer to the curing salt that follows the North American standard, called instacure#1, or, as it is commonly called in Brazil, curing salt 1.

Does your curing salt contain different amounts of Sodium Nitrite than what was used in the calculation? Use our Food Additive Calculator

If you want to check and do your analysis and calculations (recommended), see the FSIS document

What is the difference between Curing Salt 1 and Curing Salt 2?

To understand the difference between these types of curing salt, read the post Curing salt 1 and Curing salt 2.

Is the use of curing salt mandatory?

The majority of processed meat products, such as salami, sausages, bratwurst, bacon, ham and mortadella intended for sale must contain sodium nitrite, which is generally added in the form of curing salt. States and municipalities, through specific secretariats, follow national guidelines and certify establishments and products for sale within their territorial limits.

For home production intended for personal consumption, use is optional. Each person must evaluate the risks and benefits and decide whether or not to use curing salt.

Botulism

This is one of the biggest dilemmas when we think about not using curing salt. There is some controversy about the health harm caused by excessive consumption of sodium nitrite, but botulinum toxin is real and dangerous. Coming from “botulus”, sausage in Latin, botulism is not caused by the bacteria clostridium botulinum itself, but by the toxin generated by the bacteria, therefore there is no point in eliminating the bacteria, it is necessary to ensure that there has been no contamination. This bacteria does not develop at pH < 4.5 (acidic), that is, an important factor is to ensure acidity in the products. When preparing cured meat, such as salami, for example, it is recommended to monitor the acidity of the product throughout the process to ensure it has the correct pH. A combination of factors (protection barriers) is ideal to guarantee the safety of a product. See the main protection barriers in the table below.

Although it is possible to prevent botulism without the action of curing salt, nitrite is still used due to a combination of factors and mainly due to the other benefits obtained, such as color and flavor.

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