What are the common preservatives used in the personal care industry?

Isothiazolinones 【CAS】26172-55-4, 2682-20-4; Molecular formula: C21H38NCl; Relative molecular mass: 115.16. Structural formulas: 2-Methyl-4-isothiazolin-3-one (MI); 5-Chloro-2-methyl-4-isothiazolin-3-one (CMI). I. Properties and uses: Isothiazolinones are primarily composed of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI). Isothiazolinones also exert a bactericidal effect by breaking the bonds in bacterial and algal proteins. Upon contact with microorganisms, isothiazolinones can rapidly and irreversibly inhibit their growth, leading to the death of those microbial cells; as a result, they have a strong inhibitory and lethal effect on common bacteria, fungi, algae, and others. It features high killing efficiency and good degradation properties, as well as the advantages of no residue formation, safe operation, good compatibility, strong stability, and low usage costs. It is miscible with chlorine and most anionic, cationic, and non-ionic surfactants. At high doses, isothiazolinones have a significant effect on the removal of biofouling. Isothiazolinone is also a broad-spectrum, highly effective, low-toxicity, non-oxidizing biocide. It is widely used in industries such as oil fields, papermaking, pesticides, cutting oils, leather, inks, dyes, and tanneries. II. Quality Indicators Item Indicator Category 1 Category 2 Appearance Amber-colored transparent liquid Light yellow or light green transparent liquid Active ingredient content % ≥ 14.0 1.50 pH value 1.0–4.0 2.0–5.0 Density (20°C), g/cm3 ≥ 1.25 1.02 CMI/MI (mass percentage) 2.5–4.0 2.5–4.0 Note: The factory can produce products with different concentrations such as 2%, 4%, 8%, etc., according to customer requirements. III. Usage Method When using isothiazolinones and similar products as sludge removers, the dosage concentration should be 150–300 mg/l ； When used as a fungicide, it should be applied every 3–7 days at a dosage of 80–100 mg/L. It can be used simultaneously with oxidizing disinfectants such as chlorine, but cannot be used in cooling water systems containing sulfides. Thiazolidines work better when combined with quaternary ammonium salts. When used as an industrial fungicidal and bactericidal agent, the typical concentration of isothiazolinones is 0.05–0.4%.

Hey, how effective are the bactericides you mentioned? There are many types of preservatives used in cosmetics these days, and their methods of use vary. It seems there are also products like triclosan, IPBC, ZPT, OIT, BIT, etc. I’d like to know more about these bactericides: which ones are environmentally friendly and effective?

1. It can be said that carbomer is the most widely used preservative in liquid detergents, including those used for cleaning cosmetics. Moreover, carbazone also has antibacterial properties; for example, it is used as a bactericidal and algaecidal agent in the water treatment industry. 2. Isothiazolinones are also active ingredients in carbamazepine; as mentioned in the above information, there are two components. 3. There are many suppliers of Carson products, including both imported and domestic ones. Romand Hus has the most classic products, with S&M and Thor available as well. Domestically produced versions are available; the HuaKe 88 model from Shaanxi Petrochemical Institute offers the most reliable quality, while many other manufacturers such as Shandong Taihe also produce such products. Additionally, triclosan is quite effective in itself; it has been used in soaps, shampoos, toothpaste, and other products. However, it was reported by the British last year to be capable of reacting with sodium hypochlorite in tap water to produce chloroform, which is why large-scale manufacturers are now afraid to use it. IPBC is oil-soluble and is generally used in creams. ZPT, zinc pyrithione, is generally used in shampoos as an anti-dandruff and anti-itching agent. Head & Shoulders uses ZPT. The other two don’t interact much! Hope this helps!

What I know is that preservatives are food additives used to maintain the original quality and nutritional value of foods; they inhibit the growth and reproduction of microorganisms, preventing the food from spoiling and thus extending its shelf life. The mechanisms by which preservatives exert their antiseptic effect are roughly as follows: first, they interfere with the enzyme systems of microorganisms, disrupt their normal metabolism, and inhibit enzyme activity. Second, it causes the proteins of microorganisms to coagulate and denature, disrupting their survival and reproduction. Third, it alters the permeability of the cell membrane, inhibiting the elimination of enzymes and metabolic products within the cell, thereby causing its inactivation. When it comes to preservatives, people often think they are harmful; in fact, when used within safe limits, they have no toxic side effects on the human body. There are strict regulations regarding the use of preservatives in our country; preservatives must meet the following standards: 1. Their rational use is harmless to the human body ； 2. Does not affect the gut microbiota ； 3. It can be degraded in the digestive tract into normal components of food ； 4. Does not affect the use of antibiotic drugs ； 5. It does not produce harmful components during food heat treatment. To date, our country has approved 32 food preservatives for use, among which the most commonly used ones are sodium benzoate and potassium sorbate. Sodium benzoate is more toxic than potassium sorbate, and at the same acidity level its antibacterial efficacy is only 1/3 that of sorbic acid; therefore, many people are gradually switching to potassium sorbate. However, due to its low cost, sodium benzoate is still widely used in China, mainly in carbonated beverages and fruit juice drinks. Potassium sorbate has strong antibacterial properties and low toxicity; it can participate in the body’s normal metabolism and be converted into CO2 and water. Looking at the development trends of preservatives, bio-preservatives produced through biological fermentation will be the trend for the future. First, the following provides a brief introduction to the product properties, anti-corrosion mechanisms, and application areas of the commonly used preservatives in our country. 1. Benzoic acid and its salts, white granules or crystalline powder, odorless or with a slight benzoin scent. Antimicrobial mechanism: Sodium benzoate has high lipophilicity, allowing it to easily penetrate cell membranes and enter cells. It disrupts the permeability of these membranes, inhibits their ability to absorb amino acids, and suppresses the activity of cellular respiratory enzymes, thereby achieving an antimicrobial effect. The optimal pH for its antiseptic effect is 2.5–4.0; in products with a pH above 5.0, the bactericidal effect is not very satisfactory. Because its safety level is only 1/40 that of potassium sorbate, Japan has completely banned its use in food. 2. Sorbic acid and its salts, white crystalline powder or slightly yellow crystalline powder or flaky in appearance. Potassium sorbate is an acidic preservative with strong antibacterial properties; it inhibits the growth and reproduction of molds. It exerts its preservative effect by suppressing the dehydrogenase system in microorganisms. It has an inhibitory effect on bacteria, molds, and yeasts. Its antiseptic effect is significantly higher than that of benzoates, being 5-10 times that of benzoates. The product has low toxicity, equivalent to half that of table salt. Its anti-corrosion effect weakens as pH increases, with the best anti-corrosion effect at pH=3. It retains antibacterial activity at a pH of 6, but the minimum concentration must not be lower than 0.2%. Its toxicity is even lower than that of parabens. In our country, it can be used in soy sauce, vinegar, pasta sauces, beverages, jams, and more. 3. Dehydroacetic acid and its sodium salts: Both dehydroacetic acid and its sodium salts are white or light yellow crystalline powders; they are stable to light and heat, degrade into acetic acid in aqueous solutions, and are non-toxic to humans. It is a broad-spectrum preservative that exerts a strong inhibitory effect on bacteria, molds, and yeasts in food. It is widely used for preserving the freshness of meat, fish, vegetables, fruits, beverages, pastries, and more. 4. Parabens (i.e., p-hydroxybenzoate esters), with products including methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, etc. Among them, butyl paraben has the best preservative effect. In our country, ethyl and propyl parabens are mainly used. Butyl paraben is the most commonly used in Japan. The preservative mechanism of parabens is to destroy the cell membranes of microorganisms, cause denaturation of proteins within the cells, and inhibit the activity of the cellular respiratory enzyme systems. The antibacterial active component of parabens acts mainly in its molecular form; since the hydroxyl groups in its molecules have been esterified, they no longer ionize, and 60% of these molecules remain at a pH value of 8. Therefore, parabens exhibit good efficacy within the pH range of 4–8. It does not change with pH levels, offers stable performance, and has lower toxicity than benzoic acid. It is a broad-spectrum preservative. Since paraben esters are insoluble in water, they are first dissolved in ethanol before use. To enhance the preservative effect, it is best to use a mixture of two or more such esters. Ethyl paraben is generally used in fruit drinks, and propyl paraben is also generally used in fruit drinks. 5. Sodium diacetate is a preservative commonly used in pickled foods; it is safe and non-toxic, and has an excellent preservative effect. Its final breakdown products in the human body are water and carbon dioxide. It shows a significant inhibitory effect on Rhizopus nigricans, Aspergillus flavus, Listeria, etc. In pickled products, a combination of 0.2% sodium diacetate and 0.1% potassium sorbate yields excellent preservation effects. 6. Calcium propionate appears as white crystalline particles or powder; it is odorless or has a slight propionic acid smell. It is stable to light and heat and soluble in water. Propionic acid is produced as a result of the oxidation of amino acids and fatty acids in the human body, so calcium propionate is a preservative with high safety levels. No limits are set for its ADI (allowable daily intake per kilogram of body weight). It has an inhibitory effect on molds, a minor inhibitory effect on bacteria, and no effect on yeast. It is commonly used in the fermentation of flour products and to prevent mold growth in cheese products. 7. Sodium lactate is a colorless or slightly yellowish transparent liquid with no distinct odor, though it has a slight salty-bitter taste. It is miscible with water, ethanol, and glycerin. The typical concentration is 60%-80%, with a maximum usage limit of 30g/KG at a concentration of 60%. Sodium lactate is a new type of preservative used primarily in meat and poultry products; it has a strong inhibitory effect on bacteria in meat products. Such as Escherichia coli, Clostridium botulinum, Listeria, etc. It enhances food safety by inhibiting pathogenic bacteria in food. Enhances and improves the flavor of meat, and extends its shelf life. Sodium lactate exhibits good dispersibility in raw meat, as well as strong water-absorbing properties, which effectively prevents dehydration of the raw meat and thus helps to maintain its freshness and moisture. It is mainly suitable for barbecued meat, ham, sausages, poultry products such as chicken and duck, as well as marinated and pickled products. Reference formula for preserving freshness in meat products: sodium lactate: 2%, sodium dehydroacetate: 0.2%. Second, biological food preservatives: The production of biological preservatives in China began with nisin, and this has been going on for ten years now. Over the past decade, certain progress has been made in the research, production, and application of biological preservatives. GB2760 permits the use of nisin and natamycin; since 2006, polylysine has been developed (now available from four companies). Applications to include polylysine in GB2760 are currently under consideration, and it is expected to be available on the market soon. In addition, products on the market claim to be biological preservatives but are actually composite formulations. 1. Nisin is a peptide compound composed of various amino acids, and it can be absorbed and utilized by the human body as a nutrient. It can effectively inhibit Gram-positive bacteria, and in particular has a good inhibitory effect on bacterial spores. It can effectively inhibit food contamination caused by Clostridium botulinum, Staphylococcus aureus, Hemolytic streptococcus, Bacillus subtilis, Bacillus stearothermophilus, and others. It is generally ineffective against molds, yeasts, and Gram-negative bacteria. The antibacterial mechanism against bacteria includes the ability to inhibit the biosynthesis of peptidoglycan in the cell wall. The optimal pH for activity is 3; under alkaline conditions, its solubility is very low and its stability is poor, hence it does not provide significant preservative effects on alkaline foods. 2. Natamycin (also known as Mycostatin): Natamycin is a natural, broad-spectrum, highly effective and safe inhibitor of filamentous fungi such as yeasts and molds. It not only suppresses these fungi but also prevents the production of mycotoxins. Natamycin is harmless to humans, is difficult to be absorbed by the human digestive tract, and it is hard for microorganisms to develop resistance to it. Due to its low solubility and other characteristics, it is commonly used as a preservative on the surface of food. Natamycin is currently the only antifungal microbial preservative available internationally. In 1997, China’s Ministry of Health officially approved natamycin as a food preservative. Currently, this product is widely used in over 50 **. It is mainly used in the production and preservation of foods such as dairy products, meat products, fermented beverages, and drinks. 3. Polylysine: it is a peptide with antibacterial properties produced by streptomycin; once it enters the human body, it can be completely digested and absorbed. It not only has no toxic side effects but can also serve as a source of lysine. It features a broad antibacterial spectrum, good water solubility, safety, and a wide range of antibacterial activity. Lysine fermentation broth has an inhibitory effect on various bacteria. Among them, Staphylococcus aureus, Bacillus subtilis, and Rhodotorula have a significant effect. At the same time, polylysine also possesses certain antiphage capabilities. It can bind to the cell membrane, disrupt the membrane structure of microorganisms, interfere with the transfer of substances, energy, and information within cells, and cause the rupture of the lysosomal membranes inside the cells, thereby inducing autolysis in the microorganisms and ultimately leading to cell death. The application of polylysine is still in the research and development stage, and no hygiene standards for its use have been established in the food industry yet. III. Types and Application Areas of Food Preservatives
Types of Food Preservatives Application Areas
Benzoic acid and its salts Carbonated beverages, low-salt pickles, preserved fruits, wine, fruit wine, soft candies, soy sauce, vinegar, jams, fruit juice beverages, concentrated fruit and vegetable juices used in the food industry.
Potassium sorbate In addition to the above, it is also used in fish, meat, eggs, poultry products, for preserving fruits and vegetables, in collagen-based food coatings, jellies, lactic acid bacteria beverages, pastries, fillings, bread, mooncakes, etc.
Sodium dehydroacetate Tofu sticks, pickles, orange juice concentrate.
Propyl paraben For preserving fruits and vegetables, fruit juice beverages, jams, pastry fillings, egg yolk fillings, carbonated beverages, vinegar, soy sauce.
Calcium propionate Wet dough products (noodles, wonton wrappers), bread, vinegar, soy sauce, pastries, soy-based foods.
Sodium diacetate Various types of pickles, as well as in flour and dough. Sodium lactate is used in barbecued meats, ham, sausages, poultry products, as well as marinated and pickled foods. Nisin: Canned foods, plant-based protein beverages, dairy products, meat products, etc. Natamycin: Cheese, meat products, wine, fruit juice beverages, tea beverages, etc. Hydrogen peroxide is used to preserve fresh cow’s milk and packaged dried tofu. Fourth, how to use food preservatives correctly – adding food preservatives. First and foremost, it must be used strictly in accordance with the dosage and scope of use specified by food hygiene regulations, on the premise that it is non-toxic to the human body. At the same time, to achieve the best results from food preservatives, it is necessary to pay attention to various factors that affect their use and apply them flexibly in practice. 1. pH value and water activity. In water, certain preservatives are in an ionization equilibrium state. For example, acid-type preservatives rely mainly on the action of the uncharged acid for their preservative effect; such preservatives work well at low pH values. A high activity of water facilitates the growth of bacteria and molds. The water activity required for the survival of most bacteria is above 0.9, while that for most molds is below 0.7. Reducing the water activity helps enhance the preservative’s antiseptic effect. Adding electrolytes to water, or other soluble substances, can reduce the activity of water when a certain concentration is reached, thereby enhancing the effectiveness of preservatives. 2. Combined use of preservatives. Various preservatives have certain ranges of effectiveness; no single preservative can inhibit all microbial organisms, and many of these microorganisms may also develop resistance. Therefore, preservatives with different ranges of action should be used in combination. When used in combination, preservatives may have three effects, one of which is a synergistic or additive effect ； One is the increase or additive effect ； There is also an antagonistic effect. Generally, they are used in combination with other preservatives of the same type. Such as acidic preservatives and their salts, along with several esters of the same acid used in combination. Combining long-acting preservatives with those that act quickly but have lasting effects can also enhance the preservative effect. Some metal salts are resistant to preservatives. For example, calcium oxide can slightly weaken the antibacterial effects of sorbic acid and benzoic acid. 3. Duration of use of preservatives: The effectiveness of the same preservative can vary depending on when and how it is added. It is essential to first ensure that the food itself is in good sanitary conditions, and to add preservatives during the induction period of bacteria. If bacterial proliferation enters the logarithmic phase, the effectiveness of preservatives diminishes. Preservatives should generally be added early; adding them sooner yields better results and requires less amount. The more severe the contamination of food with bacteria, the weaker the effect of preservatives; if the food has already spoiled, no preservative can reverse that situation. 4. The impact of food ingredients and components. The effectiveness of preservatives is influenced by the raw materials and ingredients of the food. Flavorings, seasonings, emulsifiers, etc. in foods have antibacterial properties. Salt, sugars, and ethanol can reduce the activity of water. Certain components in food react with preservatives, which may render the preservatives partially or completely ineffective. It can also be broken down by microorganisms in food; sorbic acid can be reduced to sorbitol by lactic bacteria, which can serve as a carbon source for them. The development of preservatives in our country has entered a period of rapid growth; we are now a major producer and consumer of sodium benzoate, with the production of potassium sorbate accounting for 40% of global consumption. With the improvement of people’s living standards and increasing focus on health, along with the progress in food engineering technology, the food industry, driven by market forces, is actively moving in the direction of being \"green\" and \"natural.\" The development and application of natural, safe, and efficient functional food preservatives will become a focus of future research.