| HS Code | 577601 |
| Chemical Name | Potassium (2E,4E)-hexa-2,4-dienoate |
| Molecular Formula | C6H7KO2 |
| Molecular Weight | 150.22 g/mol |
| Cas Number | 24634-61-5 |
| Ec Number | 246-376-1 |
| E Number | E202 |
| Appearance | White crystalline powder or granules |
| Water Solubility | 67.6 g/100 mL at 20 °C |
| Melting Point | 270 °C (decomposes) |
| Ph | 7.0–8.0 (10% aqueous solution) |
| Density | 1.363 g/cm³ at 20 °C |
| Storage | Cool, dry, well-ventilated area; keep sealed to avoid moisture absorption |
| Shelf Life | 24 months if stored properly |
As an accredited Potassium Sorbate factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Potassium Sorbate, 25 kg net weight, packaged in multi-layer kraft paper bags with PE liner to ensure freshness. |
| Container Loading (20′ FCL) | 20′ FCL of Potassium Sorbate: 20-foot full container load, palletized in 25kg bags, safely secured and ventilated. |
| Shipping | Potassium Sorbate ships as a non-hazardous, stable white crystalline powder in sealed polyethylene-lined bags, drums, or bulk containers. Protect from moisture, heat, and incompatible oxidizers. Store in a dry, ventilated area and follow local chemical transport regulations. Standard ground or freight shipping applies. |
| Storage | Store Potassium Sorbate in a cool, dry, well-ventilated area in a tightly sealed container. Protect it from moisture, direct sunlight, and excessive heat. Avoid contact with strong oxidizing agents. Keep away from food and beverages. Under proper conditions, it remains stable for up to two years. |
| Shelf Life | Shelf life is typically two years when stored in a cool, dry place in sealed original containers. |
Post-fermentation stabilization lines for sweet rosé and fruit wines typically dose a 25% w/v aqueous potassium sorbate solution after the final clarification pass and before membrane filtration. The addition rate is set at 200 mg/L potassium sorbate, equivalent to 149 mg/L sorbic acid, and remains below the 200 mg/L sorbic-acid ceiling in the OIV International Code of Oenological Practices; U.S. wine operations may operate under 27 CFR 24.246 at a maximum of 300 mg/L as sorbic acid. The salt is introduced through an in-line dosing pump into a closed stainless-steel tank during recirculation, typically 30–60 min, after malolactic conversion has fully completed and after cold stabilization and crossflow filtration have removed gross yeast cells. Terminal products include semi-sweet white wines, sweet rosé, hard cider with residual sugar above 5 g/L, mead, and fruit wines. The critical process boundary is malolactic completion: residual lactic acid bacteria can metabolise sorbate to geranium-like off-odour compounds, so addition is withheld until malolactic conversion has ceased and the free SO₂ molecular fraction is maintained at no less than 0.8 mg/L. At wine pH 3.2–3.8, the undissociated sorbic acid fraction is 0.90–0.96 for pKa 4.76 at 25°C, but this high activity is the same property that makes sorbate unsuitable for unfiltered bottle fermentations. The 0.45 µm membrane filtration step immediately after dosing removes sorbate-insulted cells before final packaging.
Across the pH ranges relevant to the scenarios below, the undissociated sorbic acid fraction at 25°C is calculated as follows:
| pH at 25°C | Undissociated sorbic acid fraction |
|---|---|
| 3.0 | 0.98 |
| 4.0 | 0.85 |
| 4.5 | 0.65 |
| 5.0 | 0.37 |
| 5.5 | 0.15 |
| 6.0 | 0.055 |
High-moisture processed cheese lines operating at 44–60% moisture and pH 5.2–5.8 present a preservation problem that potassium sorbate addresses only within a narrow pH-dependent window. Under 21 CFR 133.169, pasteurized processed cheese may contain potassium sorbate at a maximum of 0.3% by weight calculated as sorbic acid, and Regulation (EC) No 1333/2008 Annex II permits 2000 mg/kg as sorbic acid in processed cheese. Dry potassium sorbate is pre-blended with emulsifying salts such as sodium citrate and disodium phosphate before entering a scraped-surface cooker; direct steam injection raises the emulsion to 85–95°C for 2–5 min, and the finished hot product is filled into blocks, slices, or portion-controlled cups. Terminal product types include sliceable processed cheese, spreadable cheese, block processed cheese, and retorted cheese sauces. The formulation addition falls between 0.10% and 0.25% w/w as sorbic acid in the finished product, with the upper boundary reserved for pH values above 5.5. At pH 5.5, only 15% of the preservative remains as undissociated sorbic acid; at pH 6.0 the fraction drops to 5.5%, which is why cheese plants using alkaline emulsifying salts monitor batch pH before sorbate addition rather than rely on a fixed weight. Potassium sorbate does not inhibit Clostridium spores, so process-cheese operations with ambient distribution combine sorbate with nisin or reduced headspace oxygen, and surface mold on cheese blocks may require a separate natamycin coating. Aseptic filling below 10°C after cooking is maintained because prolonged holding at high temperature in contact with oxidizing agents can accelerate sorbate degradation.
Cosmetic O/W emulsion lines that remove parabens often shift to potassium sorbate in low-pH systems, but the substitution requires reformulation around the acid dissociation equilibrium. Regulation (EC) No 1223/2009 Annex V lists sorbic acid and its salts as a permitted preservative at a maximum concentration of 0.6% as sorbic acid in ready-for-use preparation, and preservation efficacy is validated under ISO 11930:2019 challenge testing with Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus brasiliensis. The salt is dissolved in the heated water phase at 50–60°C before oil-phase addition, with pH adjusted to 4.5–5.0 using citric acid, followed by high-pressure homogenization at 300–800 bar for emulsion development. Typical inclusion is 0.20% w/w as sorbic acid in low-pH face creams and body lotions, while diluted surfactant systems such as body wash and wet wipes may use 0.10–0.30% w/w. Terminal product types include O/W facial creams, body lotions, shampoos, body washes, micellar waters, and preservative-boosted wet wipes. The boundary condition is pH 5.5: above this value the undissociated fraction falls below 15%, so formulations at pH 5.5–6.0 require either the legal maximum or a second preservative system. Potassium sorbate is incompatible with strong oxidizing agents such as hydrogen peroxide, ozone, and peroxide-generating preservatives, and trace metal ions from batch tanks can catalyse oxidative discoloration unless a chelator such as disodium edetate is added at 0.01% w/v. Production lines with cold-processing capability benefit from a pre-dispersion of potassium sorbate in propylene glycol or glycerin to avoid localized concentration gradients during low-energy mixing.
Because chemically leavened tortilla dough contains no active yeast fermentation to disrupt, potassium sorbate is added at the mixing stage at 0.2% of flour weight to control surface mold and rope-forming bacteria. In yeast-raised bakery products, direct dough incorporation above 0.1% inhibits Saccharomyces cerevisiae proofing activity and is avoided; instead, a 20% w/v potassium sorbate solution is sprayed onto the product surface after baking at 0.10–0.15% by product weight. Compliance falls under 21 CFR 182.3640 GRAS for food use, while European tortilla and fine bakery formulations use sorbates under Regulation (EC) No 1333/2008 Annex II at category-specific maximum 2000 mg/kg as sorbic acid. Production lines for tortillas run continuous tunnel ovens at 200–260°C with 20–40 s bake time, followed by forced-air cooling to 25–30°C within 8–12 min before packaging; the sorbate solution is applied on the cooling conveyor through atomizing spray bars calibrated to the belt load. Terminal products include wheat flour tortillas, corn tortillas, naan, pizza bases, croissants, and sliced bread. In high-pH dough systems above pH 6.0, the undissociated acid fraction is below 5.5%, and mold inhibition shifts to surface treatment with acidified spray solutions containing potassium sorbate plus fumaric or citric acid to depress the surface micro-pH. Published data for tortilla-specific shelf-life extension with potassium sorbate is limited to challenge studies and commercial belt-line validation rather than continuous process simulation.
Semi-moist pet food processing applies potassium sorbate in the liquid coating system rather than in the dry mix because the preservative must remain at the product surface where water activity permits mold germination. Under 21 CFR 582.3640, potassium sorbate is recognized as GRAS for use in animal feed, and the European feed additive framework Regulation (EC) No 1831/2003 lists sorbates as technological preservatives for complete feed and complementary pet food; AAFCO Official Publication also permits the compound in animal food. A 20% w/v aqueous solution is prepared with phosphoric acid to reduce pH to 4.0–4.5, then sprayed onto cooled extruded semi-moist pieces in a vacuum drum coater at 0.10–0.30% w/w of finished piece weight, equivalent to 1000–3000 mg/kg potassium sorbate in the final product. Coating retention time is 5–10 min under vacuum pulsing, after which the coated pieces are air-dried to remove surface moisture before flow-wrap packaging. Terminal products include semi-moist dog treats, cat morsels, jerky-type chews, and kibble with a soft-moist core. The coating boundary is water activity: at aw below 0.65, mold dormancy reduces the measurable efficacy of the preservative, so the compound is not relied upon as the sole preservation mechanism in dry extruded kibble. In semi-moist formulations with aw 0.65–0.75, potassium sorbate suppresses yeast and mold growth but has limited activity against spore-forming bacteria, requiring additional acidulant control and low-temperature storage during distribution.
Oral liquid manufacturing lines use potassium sorbate as an antimicrobial preservative in sugar-containing syrups and aqueous suspensions where pH can be maintained below 5.5. The USP–NF Potassium Sorbate monograph, USP <51> Antimicrobial Effectiveness Testing, and Ph. Eur. 5.1.3 Efficacy of Antimicrobial Preservation define the acceptance criteria for preservative performance across Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Aspergillus brasiliensis. The compound is dissolved in purified water at 20–25°C and added to the cooled syrup phase after sucrose inversion and filtration; typical use concentration is 0.10–0.30% w/v in oral syrups and suspensions, while topical gels are preserved with 0.05–0.20% w/v. Stainless-steel mixing vessels with bottom-mounted stirrers are preferred, and the solution is adjusted to pH 4.5–5.0 with citric acid before final volume adjustment. Terminal products include pediatric antipyretic syrups, oral electrolyte solutions, cough syrups, and topical hydrogel wound dressings. Operational boundaries include avoidance of alkaline buffers, which shift the equilibrium toward the ionized form and reduce preservative activity below the pharmacopoeial acceptance threshold, and exclusion of strong oxidizing agents or ultraviolet-degrading package materials. A chelator such as disodium edetate at 0.01% w/v is commonly dissolved with potassium sorbate to bind trace metals that accelerate oxidative browning in high-sugar syrup bases.
| Application | Regulatory reference | Maximum or typical use | Validation / limit basis |
|---|---|---|---|
| Wine and cider | OIV International Code of Oenological Practices; 27 CFR 24.246 | 200 mg/L sorbic acid (OIV); 300 mg/L (U.S.) | Residual sugar stability challenge |
| Processed cheese | 21 CFR 133.169; Regulation (EC) No 1333/2008 Annex II | 0.3% w/w as sorbic acid (FDA); 2000 mg/kg (EU) | Mold challenge at pH 5.2–5.8 |
| Cosmetics | Regulation (EC) No 1223/2009 Annex V | 0.6% as sorbic acid ready-for-use | ISO 11930:2019 |
| Bakery and tortilla | 21 CFR 182.3640; Regulation (EC) No 1333/2008 Annex II | 0.2% flour weight dough; 0.10–0.15% surface spray | Shelf-life visual mold count |
| Pet food | 21 CFR 582.3640; Regulation (EC) No 1831/2003; AAFCO | 0.10–0.30% w/w finished product | Water activity challenge 0.65–0.75 |
| Oral liquids | USP–NF; USP <51>; Ph. Eur. 5.1.3 | 0.10–0.30% w/v | Antimicrobial effectiveness testing |
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Potassium sorbate, the potassium salt of (2E,4E)-hexa-2,4-dienoic acid, is supplied as a white to pale-yellow crystalline powder, granule, or spherical prill under the additive designator E 202 and Chemical Abstracts Service registry 24634-61-5. The empirical formula is C6H7KO2, the molar mass is 150.22 g/mol, and the compound dissociates in water to release sorbic acid. Regulatory recognition for food use includes FDA 21 CFR 182.3640 as a substance generally recognized as safe, EU Regulation 1333/2008 Annex II as E 202, and the Codex GSFA under INS 202. Commercial product grades are differentiated by particle form, bulk density, and purity documentation; the principal food-grade material conforms to the FCC 15 monograph and EU 231/2012 purity criteria. Its central technical advantage over free sorbic acid is water solubility: potassium sorbate dissolves to approximately 58 g/100 mL at 20 °C, whereas sorbic acid remains near 0.16 g/100 mL. This makes the salt the preferred input for pump metering into liquid processing lines, beverage syrup tanks, and aqueous preservation systems.
Antimicrobial action is associated with the undissociated sorbic acid molecule rather than the potassium ion. Sorbic acid has a dissociation constant pKa of 4.76 at 25 °C; therefore, decreasing product pH shifts the equilibrium toward the neutral acid. At pH 4.0 the undissociated fraction is 85.2%, at pH 5.0 it is 36.5%, and at pH 6.0 it falls to 5.4%. Aqueous products with pH above 6.5 retain less than 2% of the active form, and preservative loading must be raised so far that off-taste and cation contribution become operationally unacceptable. The practical window is therefore pH 3.0–6.5; below pH 3.0, free sorbic acid may precipitate in high-dose concentrates because the uncharged form has very low water solubility.
| pH at 25 °C | Undissociated sorbic acid fraction | Processing implication |
|---|---|---|
| 2.5 | 99.5% | High activity, but free sorbic acid can precipitate in concentrated syrups or stock solutions. |
| 4.0 | 85.2% | Upper beverage acidulant range; effective mould and yeast control. |
| 4.76 | 50.0% | Dissociation midpoint; buffer capacity and pH stability become critical. |
| 5.0 | 36.5% | Still functional in cheese and low-salt foods, but dose-response narrows. |
| 6.0 | 5.4% | Marginal activity; only high-dose applications with validated challenge studies. |
| 6.5 | 1.8% | Operational ceiling for most aqueous foods; replacement preservative required above this pH. |
Microbial susceptibility is not uniform. Under pH 4.5 broth conditions, published minimum inhibitory concentrations for common spoilage moulds often fall between 0.02% and 0.08%, but strain-specific values must be validated with the product’s water activity, temperature history, and preservative partitioning. Potassium sorbate inhibits spore germination and mycelial growth rather than eliminating heat-resistant ascospores; it should not be used as the sole control for thermally under-processed low-acid systems. In high-sugar syrups, available water is low, and the effective preservative demand may be lower at equivalent pH; however, published data for this specific configuration is limited.
Commercial potassium sorbate for dry blending is not a single physical entity; suppliers grade the material as fine powder for rapid dissolution, compacted granules for low-dust weighing rooms, and beaded prills for high-speed auger and vibratory filling. A typical granular product may carry a bulk density of 0.75–0.85 g/cm³, but the value is grade-specific and must be read from the buyer’s certificate of analysis. Purity and contaminant control follow the FCC 15 monograph, which specifies an assay of 98.0%–101.0% on the dried basis, loss on drying not more than 1.0%, acidity not more than 1.0% calculated as sorbic acid, and lead not more than 2 mg/kg. EU 231/2012 applies comparable criteria for E 202, including an assay of not less than 99% on the dried basis, loss on drying not more than 1.0%, acidity or alkalinity not more than 1.0%, arsenic not more than 3 mg/kg, lead not more than 2 mg/kg, and mercury not more than 1 mg/kg.
Because potassium sorbate is a salt of a weak acid, addition to an acidic beverage raises local pH until neutralized. Formulators may observe a measurable pH excursion at the point of injection; the magnitude depends on the buffer capacity of the beverage and should be determined by in-line pH logging rather than assumed from small-batch mixing. On high-speed filling lines, the preferred practice is to acidify the sorbate stock solution with citric acid to pH 4.0–4.5 before metering, or to inject through a static mixer immediately before flash pasteurization. This prevents local sorbic acid crystallization and ensures that equilibrium is reached before microbiological sampling.
Production-scale handling is influenced by the physical form. Fine powder can flash out of open mixers and adhere to sight glasses when room humidity exceeds 60% RH; granules and beads reduce dust and bridge less in hoppers. A stainless-steel ribbon blender with low-shear end plows is sufficient for dry incorporation into cake mixes and powdered drink bases, but the sorbate should be pre-blended with an excipient to avoid localized high concentration. On continuous lines, a loss-in-weight feeder paired with a static mixer handles the material more consistently than manual bag dumping. Fine organic dusts should be managed under local dust-hazard or ATEX protocols because hygroscopic caking can create buildup on auger surfaces.
The principal distinguishing variable among preservatives is pH spectrum combined with solubility. Sodium benzoate is active chiefly below pH 4.0, and in the presence of ascorbic acid and dissolved oxygen it can form benzene under heat and UV conditions in beverages; potassium sorbate extends mould and yeast inhibition to pH 6.5 and does not require the same benzene formation controls in typical acidified beverages. Calcium propionate is favored in yeast-leavened bakery products because it has low yeast inhibition; potassium sorbate, by contrast, suppresses yeast fermentation at concentrations above roughly 0.05% and is therefore normally shifted to post-bake crust sprays or non-fermented dough systems. Natamycin is a surface-only antimycotic with strong mould and yeast action but negligible antibacterial activity; potassium sorbate provides broader bacterial coverage, although it is not a high-efficacy bactericide against spore-formers or lactic acid bacteria. Parabens and phenoxyethanol remain pH-independent alternatives when the matrix exceeds pH 6.5, but they carry different regulatory and labeling constraints.
No single preservative replicates the aqueous solubility, regulatory history, and acid-compatible spectrum of potassium sorbate in acidified foods. The replacement decision is therefore matrix-specific: if the product is above pH 6.5, sorbate is mismatched; if the product is yeast-raised and heavily leavened with Saccharomyces, propionate or post-bake treatment is preferable; if only surface mould on cheese is the target, natamycin may require less total additive but is not permitted as a general aqueous preservative in most applications.
In beverage manufacturing, potassium sorbate is metered as a 5%–10% stock solution into a cooled syrup or blending tank at pH 3.0–4.5. Common use bands for non-alcoholic flavored drinks are 0.02%–0.10%, but the Codex GSFA category maximum and local legislation control the upper loading; the addition should be made before final carbonation to avoid local over-concentration. In wine stabilization, EU Regulation 1333/2008 sets the maximum residual sorbic acid from sorbates at 200 mg/L; potassium sorbate is usually added after fermentation and clarification, in combination with sulfur dioxide, because sorbate inhibits Saccharomyces and is not a sterilant for established microbial loads.
For hard and semi-hard cheese surfaces, a potassium sorbate dip or spray at 20–30 g/L is used as a mould-inhibiting treatment on rind or wrapper; direct bulk addition into curd is not universal and must follow national dairy legislation. FDA 21 CFR 182.3640 classifies potassium sorbate as GRAS, but USDA FSIS limits sorbate use in meat and poultry, and direct addition to such products may be prohibited or restricted. In bakery products, sorbate is applied as a post-bake surface spray because yeast activity in fermented dough is affected above 0.05%; encapsulated forms exist for specialty doughs, but published data for specific encapsulation configurations is limited.
In leave-on and rinse-off cosmetics, potassium sorbate is used at 0.1%–0.3% in the finished product, with an acidified pH below 5.5; EC 1223/2009 Annex V permits sorbic acid and its salts at a maximum concentration of 0.6% acid equivalent. Its limitations include a taste threshold that may appear near 500–1000 mg/kg in beverages, potential off-odour when clear packages are exposed to UV and oxidative stress, and incompatibility with high concentrations of strong oxidizing agents or certain cationic surfactants in alkaline systems. Storage should be in sealed, dry packaging below 40 °C; prolonged exposure to ambient humidity above 60% RH can cause caking unless the granule has a dedicated moisture barrier liner.