Nitrites and Starter cultures and their effects on curing meat (in simple terms)

Nitrites

Nitrites in the form of either Sodium Nitrite or Potassium Nitrite are a types of salt that are commonly used in meat processing to cure meats such as ham, bacon, and sausages. These curing agents come in many different forms but one popular curing salt is Prague Powder. If you want to know more about these cures and their application there is a blog covering that subject here. 

 The curing process involves adding nitrites to the meat, which helps preserve it by inhibiting the growth of bacteria that can cause spoilage and food poisoning. Nitrites also give cured meats their characteristic pink colour and distinct flavour.

When nitrites are added to meat, they react with certain proteins in the meat to form nitric oxide. This process is known as reducing. Nitric oxide then reacts with myoglobin, a protein in meat that gives it its red colour, to form nitrosomyoglobin. This compound is what gives cured meats their pink colour.

In addition to adding colour and flavour to cured meats, nitrites also have antimicrobial properties. They inhibit the growth of bacteria that can cause food poisoning, such as Clostridium botulinum, which produces botulinum toxin, a deadly toxin that can cause botulism.

However, it's important to note that there are concerns about the potential health risks of consuming nitrites in cured meats. As a result, many health experts recommend limiting your intake of cured meats and choosing nitrite-free or nitrite-reduced products whenever possible.

Starter Cultures

Starter cultures can also assist in the colour, texture and flavour department too. The use of starter cultures in salami-making is a process known as fermentation, and it plays an important role in developing the flavour and texture of the finished product.

Starter cultures are made up of beneficial bacteria, such as lactobacilli, that are added to the meat during the salami-making process. These bacteria feed on simple sugars which are added to the mixture and the natural sugars and other compounds in the meat, producing lactic acid as a by-product. The lactic acid helps to lower the pH of the meat, creating an environment that is hostile to harmful bacteria and helps to preserve the meat.

In addition to aiding in preservation, the fermentation process also plays a role in developing the flavour and texture of the salami. The beneficial bacteria in the starter culture break down the proteins in the meat, creating new compounds that give the salami its characteristic tangy flavour and aroma. They also help to create a softer, more tender texture in the meat by breaking down connective tissue and making the meat more succulent.

One of the most noticeable effects of fermentation in salami-making is the development of a reddish colour in the meat. This is due to the formation of nitric oxide and other compounds during fermentation, which react with myoglobin in the meat to create a red or pink colour. The use of starter cultures in salami-making helps to ensure that the fermentation process is consistent and controlled, leading to a more uniform and desirable finished product.

Protective starter cultures

To help protect against Listeria monocytogenes, some starter cultures are designed to produce bacteriocins, which are natural antimicrobial compounds that can inhibit or kill Listeria and other harmful bacteria.

Listeria monocytogenes is a type of bacteria that can cause serious illness or even death, particularly in people with weakened immune systems, pregnant women, and their unborn babies. It's a common concern in food safety, particularly in ready-to-eat foods like deli meats, soft cheeses, and smoked fish.

These starter cultures are often made up of strains of lactic acid bacteria, such as Lactobacillus sakei or Pediococcus acidilactici, that are known to produce bacteriocins.

Using starter cultures that are specifically designed to protect against Listeria monocytogenes can be an effective strategy for reducing the risk of contamination in ready-to-eat foods. However, it's important to note that while these starter cultures can help to reduce the risk of Listeria contamination, they are not a substitute for good hygiene and proper food handling practices. It's important to follow proper food safety procedures at all times, including washing hands and surfaces, storing food properly, and cooking and reheating food to a safe temperature, to minimize the risk of foodborne illness.

Outperforming the bad guys

The beneficial bacteria also play a crucial role in outcompeting undesirable bacteria. They consume the available nutrients in the meat, leaving less food for harmful bacteria to grow and multiply. Additionally, the beneficial bacteria produce bacteriocins, which are natural antimicrobial compounds that help to kill or inhibit the growth of harmful bacteria.

By creating an acidic environment and producing bacteriocins, the beneficial bacteria in fermented sausages effectively outcompete harmful bacteria and prevent them from growing to dangerous levels. This is why it's important to use a high-quality starter culture when making fermented sausages and to ensure that the fermentation process is carried out correctly to encourage the growth of beneficial bacteria.

Acidity levels in fermented salami.

pH is an important factor when it comes to food safety because it can affect the growth and survival of pathogens, which are microorganisms that can cause illness or disease if consumed.

Pathogens have different pH requirements for growth and survival. Some pathogens, such as Salmonella and E. coli, can survive in a wide range of pH levels, while others, such as Listeria, are more sensitive to changes in pH.

Generally, acidic conditions are less favourable for the growth of most pathogens. The pH scale ranges from 0 to 14, with 7 being neutral. A pH below 7 is considered acidic, while a pH above 7 is alkaline or basic. Most bacteria that cause foodborne illness grow best in the range of pH 4.6 to 7.5. However, some pathogens, such as Clostridium botulinum, can grow in foods with a pH as low as 4.6. pH can be measured in several ways using a special pH meter or litmus paper. with meat a special meat probe attachment should be used. 

 

To prevent the growth of pathogens, it's important to ensure that the pH level of food is within a safe range. For example, in the case of canned foods, the pH level must be below 4.6 to prevent the growth of C. botulinum spores, which can survive in low-acid environments and produce the deadly botulinum toxin. In fermented foods, such as sauerkraut and yogurt, the pH level is lowered by the growth of beneficial bacteria that produce lactic acid, creating an acidic environment that is inhospitable to pathogens.

In summary, maintaining the correct pH level in food is crucial to preventing the growth and survival of pathogens that can cause foodborne illness. A pH level below 4.6 is generally considered safe for most foods, but the specific pH range for salami is anywhere between 4.6 - 5.3  to be considered safe.