Prof Dr M.Ali BATUHAN
(Food Science Expert)
In meat products, additives such as salt, nitrate, and nitrite, along with various spices depending on the type of product, are used to improve the product's color, texture, taste, aroma, and flavor, as well as to enhance its shelf life. Nitrite, a key additive, has been used for many years in meat products to develop the characteristic cured meat color, enhance flavor and texture, and to kill pathogenic microorganisms, especially Clostridium botulinum, as well as to prevent bitterness caused by oxygen. Additives should not negatively affect human health.
Nitrite reacts with secondary amines in meat, leading to the formation of carcinogenic and mutagenic N-nitroso compounds. However, the additives added to meat should be used in the allowed quantities for foods that are considered safe for human health. When the additives nitrate and nitrite in processed meat products are used above the permissible limits and consumed in those amounts, they can cause cancer, memory loss, and brain damage. For this reason, in recent years, natural, non-synthetic, plant-based preservatives have begun to be produced.
Organic acids that show antimicrobial activity in foods include lactic, acetic, citric, and benzoic acids. While these acids show antifungal activity in foods, their antibacterial effects have also been noted, though there is insufficient information on their use in all food products.
Sodium Nitrite (E250), Sodium and Potassium Nitrate (E251, E252) Usage
Nitrites and nitrates are added to easily perishable meat and meat products to preserve the meat and increase its shelf life. They also prevent the development of bad odors in meat. Nitrites provide the desired red color and help in the formation of the desired aroma. They are curing agents used to maintain microbial stability. In the production of some meat products, either nitrate or nitrite or both may be used, along with other additives and various spices, to improve the appearance, color, texture, taste, aroma, and flavor characteristics and to extend shelf life.
Nitrite-nitrate compounds are also strong antimicrobial agents. Nitrite provides significant antimicrobial effects against Gram-positive and Gram-negative bacteria but is not effective against yeast and molds. Nitrite, especially in vacuum-packed meat products, shows inhibitory effects against toxin-producing pathogens such as Clostridium botulinum and its spores. Other microorganisms affected by nitrite include Clostridium butyricum, Clostridium sporogenes, Clostridium perfringens, and Listeria monocytogenes.
Legal Regulations on Nitrate and Nitrite Usage
Nitrates (potassium nitrate, E251; sodium nitrate, E252) and nitrites (potassium nitrite, E249; sodium nitrite, E250) are officially listed as food additives in Commission Regulation (EC) No. 1129/2011. Various countries have set legal limits for nitrites and nitrates to protect consumers and preserve the quality characteristics of processed meat products. The European Union has also regulated the levels of nitrate and nitrite in meat products, specifying the allowed amounts or residue levels in products sold across member states.
The allowable amounts of nitrate and nitrite in meat products may vary depending on the type of product and the country of production. In the United States, the maximum allowable amount of sodium nitrite in ground products is 156 mg/kg, and sodium nitrate is 1718 mg/kg. In the European Union, the allowable limits for nitrate and nitrite are regulated by European Commission Directive (2006/52/EC). This directive specifies a maximum of 150 mg/kg for dried fermented meat products and 250 mg/kg for non-nitrite-containing long-aged products. Research in Korea has shown that dietary nitrate intake (390-742 mg/day) is much higher than that in European countries (52-156 mg/day) and China (422.8 mg/day), although no significant correlation between high nitrate intake and cancer was found.
Nitrate and Nitrite Safety
Due to their adverse effects on human health, nitrate and nitrite should not be present in foods above certain levels. While the consumption of nitrate and nitrite has been associated with cancer risks, it is noted that these compounds alone are not carcinogenic but may form carcinogenic compounds when they react with other components during cooking or digestion. While nitrates are not toxic by themselves, they break down into nitrite in meat, which then reacts with proteins to form N-nitroso compounds, which are carcinogenic. However, evidence of their carcinogenic potential in humans is limited.
In humans, nitrates and nitrites from food are quickly absorbed by the body, with the non-absorbed portion being excreted as nitrate. Some of the absorbed nitrate is circulated from the salivary glands, where it is converted to nitrite by oral bacteria. Nitrite, when it interacts with hemoglobin in the body, causes Fe+2 to oxidize to Fe+3, which impairs the blood's oxygen-carrying ability. Chronic nitrite poisoning may occur. Nitrite in food can also contribute to the formation of nitrosamines, some of which are carcinogenic.
Previously, nitrates and nitrites were considered precursors to N-nitroso compounds, which were classified as human carcinogens. Nitrate is converted to nitrite and enters the stomach, where the low pH conditions promote the conversion of nitrite to reactive nitrous acid. However, in 2010, the International Agency for Research on Cancer (IARC) concluded that there was insufficient evidence to classify nitrates as animal carcinogens. Additionally, recent epidemiological studies have not shown a correlation between dietary nitrate and stomach or esophageal cancer in humans. In fact, some studies suggest that nitrate may even reduce the occurrence of stomach cancer. Thus, there is still no consensus among scientists on the carcinogenic nature of nitrite.
Cutter Auxiliary Agents
In our country, all boiled sausages are produced using cold meat. The binding ability of cold meat is not as strong as that of hot meat. To enhance the binding property of cold meat, cutter auxiliary agents are used, primarily salt and some organic acids.
Salt
In trade, salt is added in small or large quantities. It serves as a flavor enhancer and preservative in foods. Besides giving flavor to the product, salt also plays a significant role in the maturation and preservation of sausages, affecting the physical-chemical and biological processes that occur during sausage maturation. Salt helps the sausage acquire its consistency by drawing water out of the meat, along with dissolved proteins. Furthermore, it reduces the water activity in the sausage, helping to stop the activity of harmful microorganisms. Salt is generally added to meat products at a rate of 2-3%.
Lactic Acid (E270) and Lactates
Lactic acid is a colorless, yellowish, slightly aromatic organic compound that plays an essential role in various fermentation processes, as well as in the maturation of meat and sausage. It helps the meat products turn red and aids in the reduction of bacteria in the intestines and the elimination of odors, thus extending the product's shelf life.
Tartaric Acid
Disodium tartrate is used as a cutter auxiliary agent. It is a white crystalline powder. In a 1% aqueous solution, its pH is 7.3. It is used in all types of meat products, including frozen meat. It is added to the sausage mixture at 0.2% of the meat portion. It helps improve the consistency of lean meat in the cutter.
Citric Acid and Citrates
Citric acid, which was originally obtained from lemon juice, is now largely produced by fermenting an Aspergillus niger culture in a carbohydrate-rich medium. The citric acid produced by fermentation is obtained as calcium salts, which are soluble in water. The esters formed by citric acid with mono- and diglycerides are used as emulsifiers in food preparation.
Ascorbic Acid and Ascorbates
Ascorbic acid and its sodium salts are the most important and effective agents in providing color formation and color stability in sausages. Ascorbic acid directly contributes to the color formation in sausages. In the production of fermented sausages, sodium ascorbate, a milder reducing agent, is used to achieve better color. The required amounts are 0.4-0.5 grams of ascorbic acid or sodium ascorbate per 1 kg of sausage mixture.
