Food Additives and Food Toxins

Benzoic Acid (E210)

• Naturally occurs in berries, plums, prunes, and some spices.
• Used as benzoic acid or benzoate (more common due to better water solubility).
• Benzoic acid's solubility in water 0.27\% at 18°C, while sodium benzoate's is 66.0 g/100 mL at 20°C.
• The undissociated form is the most effective antimicrobial agent.
• Optimum pH range is 2.5 to 4.0 (pKa of 4.2).
• Effective in high-acid foods like fruit drinks, cider, carbonated beverages, and pickles.
• Also used in margarines, salad dressings, soy sauce, and jams.
• Purpose: Antimicrobial, particularly against yeasts and molds.
• Frequently used in acidic foods.
• Allergic reactions may occur in asthma patients and individuals with aspirin sensitivity.
• Excessive intake of sodium benzoate is harmful for individuals restricting sodium consumption.
• ADI (Acceptable Daily Intake): 0–5 mg/kg body weight.
• Combined with ascorbic acid (vitamin C), it can form benzene (a potential carcinogen).

Parabens (Metilparaben, Propylparaben etc) E214, E216, E218

• Alkyl esters of p-hydroxybenzoic acid (methyl, ethyl, propyl, butyl, or heptyl).
• Colorless, tasteless, and odorless (except methyl paraben).
• Nonvolatile and nonhygroscopic.
• Solubility in water decreases with longer alkyl chain length.
• Antimicrobial activity in both acid and alkaline pH regions.
• Antimicrobial activity is proportional to the alkyl group's chain length.
• More active against molds and yeasts than bacteria; more active against gram-positive than gram-negative bacteria.
• Used in fruitcakes, pastries, and fruit fillings.
• Methyl and propyl parabens can be used in soft drinks.
• Combinations used in fish products, flavor extracts, and salad dressings.
• Purpose: Preservative against fungi and bacteria.
• Wide range of uses including bakery products, jams, syrups, some dairy products, and cosmetics.
• Potential endocrine-disrupting effects (estrogen-like).
• Caution advised for individuals with precocious puberty, infertility, or hormonal disorders.
• Consider co-exposure from other sources (cosmetics, drugs).
• Preventive approach may be preferred in sensitive groups like pregnant women, breastfeeding women, and young children.

Sorbic Acid (E200) and Derivations (Potassium Sorbate E202, Calsium Sorbate E203)

• Straight-chain, trans-trans unsaturated fatty acid (2,4-hexadienoic acid).
• Low solubility in water at room temperature (0.15 g/100 mL).
• Salts (sodium, potassium) are more water-soluble.
• Stable in dry form, unstable in aqueous solutions due to oxidation.
• Oxidation rate increases at low pH, increased temperature, and light exposure.
• Effective against yeasts and molds.
• Inhibits yeast growth in wine, fruit juice, dried fruit, cottage cheese, meat, and fish products.
• Most effective in low pH products like salad dressings, tomato products, and carbonated beverages.
• Effective level in foods: 0.5–0.30%.
• Generally doesn't affect food flavor at typical levels.
• Higher levels may be perceived as an unpleasant flavor.
• Can be degraded by certain microorganisms, producing off-flavors.
• May cause similar issues in fermented vegetables.
• Purpose: Broad-spectrum preservative against mold, yeast, and some bacteria.
• Frequently used in cheese, yogurt, dried fruits, bread, fruit juices, and some fermented products.
• Considered one of the safest preservatives.
• Rapidly broken down by metabolism and does not accumulate in the body.
• Low allergenic potential, but mild skin reactions or mucosal irritation may occur in sensitive individuals.
• Some studies suggest sorbates may cause behavioral effects when taken with colorants (especially E102, E110).
• ADI: 0–25 mg/kg body weight.

Sulfites (E220-E228) (Sodium metabisulfit, Potassium bisulfit, Sulfur dioxide)

• Sulfur dioxide and sulfites have been used as preservatives for a long time; act as antimicrobial and antioxidant agents.
• Used in wine preservation since Roman times.
• Sulfurous acid inhibits molds and bacteria, less so yeasts.
• Can control undesirable bacteria and wild yeast in fermentations without affecting SO2-tolerant cultured yeasts.
• High levels (200-500 ppm) can result in unpleasant off-flavor.
• Acceptable daily intake (ADI): 1.5 mg/kg body weight.
• Difficult to reduce SO2 use in winemaking.
• Not permitted in foods with significant thiamine content (destroys the vitamin).
• Widely used in dried fruits (up to 2000 ppm).
• Also used in dried vegetables and dried potato products.
• Volatile and easily lost to the atmosphere, so residual levels may be lower than initially applied.
• Purpose: Prevents oxidation, inhibits microorganism activity.
• Especially used in dried fruits, wine, fruit juices, pickles, potato products, and seafood.
• Can trigger asthma attacks in asthma patients.
• Side effects include headache and nausea in sensitive individuals.
• Products containing more than 10 mg/kg of sulfites must be clearly labeled in the EU and Türkiye.
• Sulfite sensitivity is an intolerance-type reaction, not an allergy.

Nitrates (E251 – Sodium Nitrate, E252 – Potassium Nitrate) Nitrites (E49 – Potassium nitrite, E250 – Sodium nitrite)

• Curing salts produce the characteristic color and flavor of cured products (bacon, ham).
• Traditionally contained nitrate and nitrite; nitrite is the active compound (discovered around 1890).
• Nitrate isn't considered essential now; may be transformed into nitrite, thus forming a reservoir for the production of nitrite.
• Both nitrates and nitrites are thought to have antimicrobial action.
• Nitrate used in Gouda cheese production to prevent gas formation by butyric acid–forming bacteria.
• Nitrite inhibits toxin formation by Clostridium botulinum (safety of cured meat products).
• Nitrosamines are powerful carcinogens, potentially mutagenic and teratogenic.
• Very small amounts of nitrosamines can form in certain cured meat products (ppm or ppb range).
• Difficult analytical procedures make it hard to get a clear picture of nitrosamine occurrence.
• Suitable modifications of process conditions can drastically reduce nitrosamine levels.
• No suitable replacement for nitrite in cured meats.
• ADI of nitrite is set at 60 mg per person per day.
• Estimated daily intake per person in Canada is about 10 mg.
• Dramatic decline in the residual nitrite levels in cured meat products in the United States.
• Current residual nitrite content of cured meat products is about 10 ppm.
• In 1975, the average was 52.5 ppm (80% reduction due to lower ingoing nitrite, increased ascorbate use, improved process control, altered formulations).
• Nitrate-nitrite intake from natural sources is much higher than from processed foods.
• Nitrate intake from 100 g of processed meat might be 50 mg; from 100 g of high-nitrate spinach, 200 mg.
• Nitrate in cured meats is insignificant compared to nitrite produced endogenously.
• Purpose: Antimicrobial, color and aroma preservative.
• Common in processed meat products.
• Critical use in products with a risk of Botulism!
• Nitrites can transform into nitrosamines in the body (especially at high temperatures or low pH), identified as potential carcinogens.
• Linked to stomach and colorectal cancer according to some studies.
• Careful consumption for children & pregnant women!
• Nitrite may increase the risk of “blue baby syndrome” (methemoglobinemia) in babies (not recommended for babies under 6 months).
• Ascorbic acid or its derivatives (E300–E304) can suppress nitrosamine formation when used with the product.

Hydrogen Peroxide

• Strong oxidizing agent and bleaching agent.
• Used for bleaching crude soya lecithin.
• Antimicrobial action used for preserving cheese milk.
• Decomposes slowly into water and oxygen (accelerated by increased temperature and catalysts).
• Antimicrobial action increases with temperature.
• In cheesemaking, milk is treated with 0.02\% hydrogen peroxide followed by catalase.
• Used for sterilizing food processing equipment and packaging material (aseptic food packaging systems).
• E code generally not used due to limited use in foods.
• Purpose: Disinfectant, bleaching and oxidizing agent.
• Used in the sterilization of liquid foods (milk, dairy, egg products, fruit juices).
• Should not leave any residue, considered a processing aid, not a food additive.
• Toxic in excess, can cause cell damage through free radical production.
• Residue can cause mucosal irritation and gastrointestinal problems.
• Use in milk used to be common, but now limited or prohibited in most countries.
• Prohibited in organic products.

Sodium Chloride

• Used for centuries to prevent food spoilage.
• Used to preserve fish, meats, and vegetables.
• Used mainly in combination with other processing methods today.
• Antimicrobial activity related to its ability to reduce water activity (aw), influencing microbial growth.
• Produces an osmotic effect.
• Limits oxygen solubility.
• Changes pH.
• Sodium and chloride ions are toxic.
• Contributes to loss of magnesium ions.
• Self-limiting use due to taste.

Bacteriocins

• Examples: Nisin – E234, pediocin, lantibiotics
• Nisin is an antibacterial polypeptide produced by some strains of Lactococcus lactis.
• Not used for therapeutic purposes in humans or animals, thus the term "antibiotic" is avoided.
• Nisin-producing organisms occur naturally in milk.
• Can be used as a processing aid against gram-positive organisms.
• Unlikely to cover up unhygienic practices, as effectiveness decreases with increased bacterial load.
• Approved for use as a food preservative in many countries.
• Used effectively in preservation of processed cheese.
• Used in the heat treatment of nonacid foods and in extending the shelf life of sterilized milk.
• Purpose: Natural antimicrobial peptides.
• Defense proteins produced by some bacteria to suppress other harmful bacteria (Listeria, Clostridium, Bacillus).
• Used in cheese, dairy products, delicatessen products, canned food and ready meals.
• Produced by probiotic bacteria (especially Lactococcus lactis), a more acceptable "clean label" additive.
• Effective against serious pathogens such as Listeria monocytogenes, making it important for nutrition in risk groups (hospitals, elderly care).
• Non-toxic: broken down by the digestive system and does not accumulate in the body.
• Synergy with probiotic products: Explaining the protective role of bacteriocins enriches functional nutrition information.
• Some may have been produced in animal-based environments.

Acids

• Examples: Citric acid (E330), Ascorbic acid (E300), Lactic acid (E270), Acetic acid (E260), Fumaric acid (E297), Malic acid (E296).
• Serve a dual purpose: acidulants and preservatives.
• Phosphoric acid is used in cola soft drinks to reduce pH.
• Acetic acid is used to provide tartness in mayonnaise and salad dressings.
• Organic acids (citric, tartaric, malic, lactic, succinic, adipic, fumaric acid) serve a similar function in various other foods.
• Straight-chain carboxylic acids (propionic and sorbic acids) are used for their antimicrobial properties.
• Propionic acid is mainly used for its antifungal properties.
• Applied as a 10\% solution to the surface of cheese and butter to retard mold growth.
• Each acid has a different source and effect profile.
• Citric Acid (E330): derived from lemon, natural and safe, but excessive consumption can damage tooth enamel.
• Acetic Acid (E260): vinegar acid, can have a digestive effect but can trigger reflux in sensitive stomachs.
• Lactic Acid (E270): naturally found in fermented products such as yogurt, can even be used in baby formulas.
• Malic Acid (E296): apple acid, safe, but can irritate the tongue due to its intense flavor.
• Ascorbic Acid (E300): acts as an antioxidant and is versatile as an additive.
• Purpose: Low pH makes it difficult for microorganisms to multiply.
• Used as part of microbial control, not as a preservative.

Antioxidants

• Examples: Ascorbic acid (E300), Tocopherols – E306-E309, BHA (E320), BHT (E321), Citric acid (E330), Gallic acid, Sulfur dioxide (E220).
• Substances that prevent or retard oxidative deterioration in foods.
• Primary antioxidants terminate free radical chains and function as electron donors.
• Include phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butyl hydroquinone (TBHQ), alkylgalates (propylgallate (PG)), and natural and synthetic tocopherols and tocotrienols.
• The most widely used compounds are vitamin C and related substances, ascorbyl palmitate, and erythorbic acid (the D-isomer of ascorbic acid).
• Chelating agents or sequestrants remove metallic ions (copper and iron) that are powerful prooxidants.
• Citric acid is widely used for this purpose.
• Amino acids and ethylene diamine tetraacetic acid (EDTA) are other examples of chelating agents.
• The level of phenolic antioxidants permitted for use in foods is limited.
• U.S. regulations allow maximum levels of 0.02\% based on the fat content of the food.
• Sometimes incorporated in the packaging materials rather than in the food itself.
• In this case, a larger number of antioxidants is permitted, provided that no more than 50 ppm of the antioxidants become a component of the food.
• Purpose: Prevents oxidation of oils, extends shelf life, prevents deterioration of color/odor.
• Especially used in foods that are sensitive to oxidation such as fatty products, meats, chips, nuts.
• Natural antioxidants (ascorbic acid, tocopherols, rosmarin extract) are generally safe, even nutritious.
• Synthetic antioxidants (BHA – E320, BHT – E321) have discussed their carcinogenic potential.
• Products containing synthetic antioxidants should be kept to a minimum in children, pregnant women and sensitive individuals.
• Additives such as E320 and E321 should be monitored carefully.
• Antioxidants naturally found in foods such as vegetables, fruits, and olive oil are much more beneficial than taking them as additives.
• Also used in cosmetic products, increasing awareness of “additives from food + external exposure”.

Emulsifiers

• Examples: Lecithin (E322), Mono- and diglycerides (E471), Polysorbates (E432–436), Sodium stearoyl lactylate (E481), Propylene glycol esters, Hardened resins.
• With the exception of lecithin, all emulsifiers used in foods are synthetic.
• All of the synthetic emulsifiers are derivatives of fatty acids.
• Lecithin is the commercial name of a mixture of phospholipids obtained as a byproduct of the refining of soybean oil.
• Phosphatidylcholine is also known as lecithin, but the commercial product of that name contains several phospholipids including phosphatidylcholine.
• Crude soybean lecithin is dark in color and can be bleached with hydrogen peroxide or benzoyl peroxide.
• Purpose: Mixing oil and water, increasing stability, creating consistency and texture.
• Widely used in products such as dairy products, chocolate, ice cream, margarine, mayonnaise, ready-made cakes, breads.
• Some only have a technical function, some can have metabolic effects in the body.
• Lecithin (E322): Natural, usually soy or egg-based → may have an allergy potential, but is a useful choline source.
• E471 (mono- and diglycerides): May be plant-based, but sometimes animal-based → caution for vegan/vegetarians!
• Some synthetic emulsifiers (especially polysorbate 80 – E433 and carboxymethyl cellulose) can damage the intestinal barrier and increase inflammation (IBS and IBD).
• Emulsifiers are often found in “ready-made” products with extended shelf life.
• They can make up for the lack of texture in gluten-free, low-fat or vegan products.

Sweeteners

• Two main groups:
  • Nutritive (caloric) sweeteners: Sorbitol (E420), Mannitol (E421), Maltitol (E965), Eritritol (E968), Xylitol (E967)
  • Nonnutritive (non-caloric) sweeteners: Aspartame (E951), Saccharin (E954), Acesulfame-K (E950), Sucralose (E955), Stevia (E960)
• Plant extracts from Stevia and Monk Fruit extract where the main sweetener is Mogroside V are plant extracts that have been approved for food uses.
• Saccharin is available as the sodium or calcium salt of orthobenzosulfimide.
• The cyclamates are the sodium or calcium salts of cyclohexane sulfamic acid or the acid itself.
• Cyclamate is 30–40 times sweeter than sucrose, and about 300 times sweeter than saccharin.
• At higher concentrations, the sweetness intensity of the synthetic sweeteners increases at a lower rate than that which occurs with sugars.
• Aspartame is a dipeptide derivative, L-aspartyl-L-phenylalanine methyl ester, which was approved in the United States in 1981, in dry beverage mixes, and in foods that are not heat processed.
• This substance is metabolized in the body to phenylalanine, aspartic acid, and methanol.
• Only people with phenylketonuria cannot break down phenylalanine. Another compound, diketopiperazine, may also be formed.
• The main limiting factor in the use of aspartame is its lack of heat stability.
• Acesulfame K is the potassium salt. It is a crystalline powder that is about 200 times sweeter than sugar.
• The sweetening power depends to a certain degree on the acidity of the food it is used in.
• Acesulfame K is reportedly more stable than other sweeteners.
• The sweet taste is clean and does not linger.
• Sucralose is a trichloroderivative of the C-4 epimer galactosucrose. It is about 600 times sweeter than sucrose and has a similar taste profile.
• One of its main advantages is heat stability, so it can be used in baking.
• Blending of nonnutritive sweeteners may lead to improved taste, longer shelf life, lower production cost, and reduced consumer exposure to any single sweetener.
• Advantages: Blood glucose and insulin response are low. It provides a controlled alternative especially for diabetic individuals. Energy intake can be reduced. Some are tooth-friendly (xylitol is used in chewing gums - can prevent cavities).
• Things to Watch Out For: Digestive system sensitivity: Sugar alcohols such as sorbitol and mannitol → can cause gas, bloating, and diarrhea when consumed excessively. Aspartame → is strictly prohibited in patients with phenylketonuria (PKU)! Pay attention to the "contains phenylalanine" warning on labels. Some synthetic sweeteners (especially saccharin, aspartame, sucralose) → there are studies that they can affect the intestinal microbiota. It is not clear but should be approached with caution. Its taste is much more intense than sugar → can change taste perception. This can increase the desire for sugary foods in some individuals.

Phosphates (E338–E341, E343, E450–E452)

• These compounds are widely used as food additives, in the form of phosphoric acid as acidulant, and as monophosphates and polyphosphates in a large number of foods and for a variety of purposes.
  • buffering agents in dairy, meat, and fish products
  • anticaking agents in salts
  • firming agents in fruits and vegetables
  • yeast food in bakery products and alcoholic beverages
  • melting salts in cheese processing
• The largest group of phosphates and the most important in the food industry is the orthophosphates.
• Too much is harmful!
• Phosphate additives are generally in “inorganic” form → their absorption in the body is very high.
• An increase in phosphorus load increases the risk of hyperphosphatemia, vascular calcification and cardiovascular diseases, especially for kidney patients.
• Even in healthy individuals, it can negatively affect bone health by disrupting the phosphate/calcium balance. It is a long-term risk factor for osteoporosis.
• Phosphoric acid + carbonated drinks =
  • Phosphoric acid, especially used in cola and caramel colored drinks, can suppress calcium absorption → threat to bone health.
• Even if it does not say “phosphate” on the labels, it is there! It may be called “emulsifier” , “stabilizer” , “acidity regulator”.
• Dietary inorganic phosphate intake should be limited for patients with chronic kidney disease (CKD), elderly individuals, and individuals who need to pay attention to calcium balance (e.g. postmenopausal women).

Coloring Agents

• Two main groups:
  • Natural colorants: Beta-carotene (E160a), Beet root (E162), Chlorophyll (E140), Curcumin (E100), Anthocyanins (E163)…
  • Synthetic colorants (azo dyes): Tartrazine (E102), Sunset yellow (E110), Allura red (E129), Brilliant blue (E133)…
• In the United States two classes of color additives are recognized: colorants exempt from certification and colorants subject to certification.
  • The former are obtained from vegetable, animal, or mineral sources or are synthetic forms of naturally occurring compounds.
  • The latter group of synthetic dyes and pigments is covered by the Color Additives Amendment of the U.S. Food, Drug and Cosmetic Act.
• In the United States these color compounds are not known by their common names but as FD&C colors (Food, Drug and Cosmetic colors) with a color and a number.
• Over the years the originally permitted fat-soluble dyes have been removed from the list of approved dyes, and only water-soluble colors remain on the approved list.
• Purpose of use: To add visual appeal to foods, compensate for natural color loss, maintain brand standards.
• Most commonly used in confectionery, beverages, desserts, sauces, ready-made soups…
• Natural ones are generally safe.
• Natural pigments such as beta-carotene, curcumin, anthocyanins also have an antioxidant effect.
• Color = can be a functional component → E.g. anthocyanins in purple fruits
• Be careful with synthetic colorants!
• Azo dyes in particular (E102, E110, E122, E129 etc.) can cause:
  • Allergic reactions
  • Hyperactivity (especially in children, associated with ADHD)
  • Immune system sensitivity
• The European Union requires the warning “May cause activity and attention problems in children” for some azo dyes.
• Eating behavior and perception:
  • Color has an appetite-stimulating effect → Can trigger overconsumption, especially in children.
  • “Natural appearance” and “healthy content” do not always coincide!
• It may be riskier in liquids:
  • In products such as carbonated drinks and sugary drinks, the combination of colorant + sweetener + acid + aroma can cause multiple exposure. A holistic approach should be taken against such products in counseling.

Nutrition Supplements

• Two fundamental reasons for the addition of nutrients to foods consumed by the public:
  • (1) to correct a recognized deficiency of one or more nutrients in the diets of a significant number of people when the deficit actually or potentially adversely affects health
  • (2) to maintain the nutritional quality of the food supply at a level deemed by modern nutrition science to be appropriate to ensure good nutritional health, assuming only that a reasonable variety of foods are consumed
• A variety of compounds are added to foods to improve the nutritional value of a product, to replace nutrients lost during processing, or to prevent deficiency diseases.
• Most of the additives in this category are vitamins or minerals.
• Enrichment of flour and related products is now a well-recognized practice.
• The U.S. Food and Drug Administration (FDA) has established definitions and standards of identity for the enrichment of wheat flour, farina, com meal, com grits, macaroni, pasta products, and rice.
• These standards define minimum and maximum levels of addition of thiamin, riboflavin, niacin, and iron.
• In some cases, optional addition of calcium and vitamin D is allowed.
• Margarine contains added vitamins A and D, and vitamin D is added to milk.
• The addition of the fat- soluble vitamins is strictly controlled, because of the possible toxicity of overdoses of these vitamins.
• The vitamin D enrichment of foods has been an important measure in the elimination of rickets.
• Another example of the beneficial effect of enrichment programs is the addition of iodine to table salt.
• One of the main potential deficiencies in the diet is calcium.
• Lack of calcium is associated with osteoporosis and possibly several other diseases.
• The recommended daily allowance for adolescents/young adults and the elderly has increased from the previous recommendation of 800–1200 mg/day to 1500 mg/day.