Sodium Benzoate-Acidic Preservative
Product Name: Sodium Benzoate
Chemical Name: Sodium Benzenecarboxylate, Benzoic Acid Sodium Salt
INCI Name: Sodium Benzoate
INS/E Number: E211
CAS Number: 532-32-1
EINECS Number: 208-534-8
Purity: ≥99.0% (Food Grade), ≥99.5% (USP/Cosmetic Grade)
Appearance: White crystalline powder or granules
Molecular Formula: C₇H₅NaO₂
Molecular Weight: 144.11 g/mol
Sodium Benzoate, E211, CAS 532-32-1, Benzoic Acid Sodium Salt
Sodium Benzoate-Acidic Preservative(CAS 532-32-1)
Sodium Benzoate (CAS 532-32-1, E211) is the sodium salt of benzoic acid, a naturally occurring carboxylic acid found in cranberries, prunes, cinnamon, and cloves. As the world's most widely used acidic preservative for over 100 years, it remains the gold standard for cost-effective broad-spectrum preservation in acidic formulations.
Its antimicrobial mechanism works by penetrating microbial cell walls and disrupting metabolic pathways, with undissociated benzoic acid (formed below pH 4.5) being the active form. It provides highly effective control against yeasts, molds, and acidophilic bacteria, particularly in acidic environments where many other preservatives lose efficacy.
Certificate of Analysis (COA)
Item | Specification | Test Result |
Product Identification | ||
Product Name | Sodium Benzoate | Sodium Benzoate |
Grade | Cosmetics / Food Grade | Cosmetics / Food Grade |
Quality Parameters | ||
Appearance | White crystalline powder | White crystalline powder |
Assay (Dry Basis) | 99.0 - 100.5% | 99.87% |
Loss on Drying | ≤1.5% | 0.32% |
pH (1% Solution) | 7.5 - 8.5 | 8.0 |
Chloride Content | ≤0.03% | 0.008% |
Sulfate Content | ≤0.02% | 0.006% |
Benzoic Acid Content | 84.5 - 86.5% | 85.2% |
Heavy Metals | ||
Lead (Pb) | ≤2 ppm | <0.5 ppm |
Arsenic (As) | ≤2 ppm | <0.5 ppm |
Mercury (Hg) | ≤0.1 ppm | <0.05 ppm |
Cadmium (Cd) | ≤1 ppm | <0.1 ppm |
Microbiological Test | ||
Total Aerobic Count | ≤1000 CFU/g | <10 CFU/g |
Yeast & Mold | ≤100 CFU/g | <10 CFU/g |
Key Benefits
✅ Naturally Occurring - Benzoic acid found naturally in cranberries, prunes, cinnamon, and cloves
✅ Proven Track Record - Over 100 years of safe use globally; most studied preservative in history
✅ Exceptional Cost-Effectiveness - Lowest cost-in-use among all broad-spectrum preservatives
✅ Broad-Spectrum Activity - Highly effective against yeasts, molds, and acidophilic bacteria
✅ Industry-Standard Synergy - 1:1 blend with Potassium Sorbate = gold standard acidic preservation system
✅ Excellent Water Solubility - 62 g/100 mL water; easy incorporation at any production stage
✅ Heat & Processing Stable - Stable to pasteurization, sterilization, and high-temperature processing
✅ HALAL/KOSHER Certified - Suitable for all dietary and religious requirements
✅ pH Optimized - Ideal for acidic formulations (pH < 4.5) where other preservatives fail
Applications
Food & Beverage Industry (Primary):
• Beverages: Carbonated drinks, fruit juices, sodas, energy drinks, iced teas
• Condiments & sauces: Ketchup, mayonnaise, salad dressings, soy sauce, pickles
• Jams & preserves: Fruit jams, jellies, marmalades, fruit preserves
• Dairy & bakery: Processed cheeses, bakery fillings, icings, pastries
• Processed foods: Margarine, processed meats, seafood products, prepared salads
Cosmetics & Personal Care:
• Rinse-off products (max 2.5%): Shampoos, conditioners, body washes, shower gels, liquid soaps
• Leave-on products (max 0.5%): Creams, lotions, serums, toners (acidic pH formulations)
• Oral care (max 1.7%): Toothpastes, mouthwashes, oral rinses, dental products
• Wet wipes: Baby wipes, cleansing wipes, antibacterial towelettes
• Acidic formulations: AHAs/BHAs products, vitamin C serums, exfoliants
Frequently Asked Questions (FAQ) & Document Request Frequently Asked Questions (FAQ) & Document Request
Q1: What is the difference between Benzoic Acid and Sodium Benzoate?
A: Benzoic Acid is the free acid form (C₇H₆O₂), while Sodium Benzoate is its sodium salt. Sodium Benzoate has dramatically better water solubility (62 g/100mL vs 0.34 g/100mL for benzoic acid), making it practical for aqueous formulations. Both convert to active undissociated benzoic acid at pH < 4.5.
Q2: What are the regulatory limits in cosmetics by region?
A:
• EU Regulation: Max 0.5% (leave-on), 2.5% (rinse-off), 1.7% (oral care) - all calculated as benzoic acid
• China: Same as EU - 0.5%/2.5%/1.7% limits per Safety and Technical Standards
• US FDA: GRAS status; generally 0.1-0.5% in cosmetics
Q3: At what pH is Sodium Benzoate most effective?
A: Sodium Benzoate is ONLY effective at pH < 4.5, with optimal activity at pH 2.5-4.0. Above pH 5.0, it is essentially inactive. This makes it ideal for acidic formulations like AHAs/BHAs, vitamin C products, and low-pH toners.
Q4: What is the classic synergistic combination with Sodium Benzoate?
A: The industry standard acidic preservation system is:
• Gold standard blend: 0.2% Sodium Benzoate + 0.2% Potassium Sorbate (pH 4.0-4.5)
• Enhanced clean system: 0.2% Sodium Benzoate + 0.2% Potassium Sorbate + 0.5% 1,2-Octanediol
This combination provides complete broad-spectrum coverage with exceptionally low total preservative load.
Q5: Is there an incompatibility with Vitamin C (ascorbic acid)?
A: At very high concentrations and elevated temperatures, Sodium Benzoate and ascorbic acid can form trace amounts of benzene. This reaction is negligible at typical cosmetic use levels and normal storage conditions. Avoid combining at >0.5% each in high-heat processed products.
Q6: Is Sodium Benzoate approved for organic or natural cosmetics?
A: Sodium Benzoate (E211) is accepted by Ecocert and COSMOS for use in natural and organic cosmetics (with concentration limits). It is NOT permitted in certified organic food products under USDA NOP standards. It is widely used in clean beauty formulations.
Q7: What are proper storage conditions?
A: Store in tightly sealed containers in a cool, dry, well-ventilated area. Sodium Benzoate is stable in air and does not require special storage beyond moisture protection. Shelf life is 24 months from manufacture under proper conditions.
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