As a high-performance feed additive, Sodium Propionate (Propionato de sodio,Propionato di sodio) features excellent mould inhibition and preservation capabilities, and is widely applied in various livestock and poultry feeds. This document systematically elaborates on its antifungal mechanism, physical properties, application scope, dosage guidelines and standardized usage precautions.

1. Mould Inhibition Performance

1.1 Mould Inhibition Mechanism

Sodium propionate is an acidic mould inhibitor. The growth and reproduction of moulds are highly dependent on environmental pH values. After being added to feed, sodium propionate decomposes into propionic acid, which effectively reduces the local pH of the feed matrix. This breaks the optimal growth conditions for moulds and restrains their proliferation.

Most moulds grow vigorously in neutral to weakly acidic environments. The acidic environment generated by propionic acid effectively suppresses the metabolic activities of moulds and inhibits their normal growth.

1.1.1 Inhibitory Effect on Aspergillus flavus

Aspergillus flavus is prone to breeding in humid feed. Its metabolite, aflatoxin, is highly toxic and causes severe damage to the liver and other internal organs of animals. Sodium propionate delivers prominent inhibitory effects on Aspergillus flavus, greatly reducing aflatoxin production and ensuring feed safety. Meanwhile, it provides broad-spectrum inhibition against various moulds and toxin-producing fungi.

1.1.2 pH Influence on Antifungal Efficacy

The antifungal performance of sodium propionate is closely correlated with feed pH. Under acidic conditions (pH ≤ 5.0), a concentration of 0.01% can effectively inhibit most moulds. When the pH value rises to 6.5, the effective inhibitory concentration needs to be increased to 0.5%. Therefore, feed formulas with high pH values require an appropriate increase in sodium propionate dosage to guarantee stable mould prevention effects.

1.2 Shelf Life Extension

Benefiting from its superior antifungal properties, sodium propionate can significantly extend the storage period of feed. Proper addition in compound feed, silage and other feed types effectively preserves feed freshness, prevents nutrient loss during storage, stabilizes nutritional value and improves feed palatability.

• Under conventional storage conditions, the shelf life of feed supplemented with sodium propionate can be extended by 3–6 months.
• Under high-temperature and high-humidity conditions, the shelf life can still be prolonged by 1–3 months.

2. Physical Properties

2.1 Appearance and Characteristics

Sodium propionate appears as white crystalline powder or spherical granules with a faint characteristic odour of propionic acid. It is freely soluble in water with a solubility of 100 g/100 mL at 20°C. The product is highly hygroscopic and prone to deliquescence in humid air.

Its uniform granular structure provides excellent dispersibility in feed, enabling even mixing and stable long-term antifungal effects in practical application. Compared with calcium propionate, sodium propionate possesses better water solubility, making it more suitable for liquid feed and feed systems that require rapid active ingredient release.

3. Scope of Application

Applicable to feeds for pigs, chickens, cattle and other livestock and poultry. It is especially suitable for the following mould-prone feed categories:

• High-protein feed: High protein content leads to high microbial contamination risks
• Aquatic bait feed: High moisture content and complex storage conditions
• Complete compound feed: Comprehensive nutrients make it vulnerable to microbial infection
• Silage: Susceptible to mould contamination during fermentation
• High-moisture grain feed: Elevated water content creates urgent mould prevention demands
• Pet feed: Requires long shelf life and strict quality standards

4. Recommended Dosage

The conventional addition dosage of sodium propionate in feed is 0.1%–0.3% (calculated as propionic acid), equivalent to 1–3 kilograms per ton of feed.

This dosage range can effectively inhibit the reproduction of harmful microorganisms, prevent feed mildew and nutrient loss, and stabilize the nutritional value and palatability of feed without adversely affecting feed flavour.

5. Usage Precautions

5.1 Dosage Adjustment According to Feed Characteristics and Environmental Conditions

Feed mildew probability is affected by storage duration, moisture content, nutritional components, external environment, post-processing status and packaging conditions, which determine the required dosage of sodium propionate:

• High-temperature and high-humidity seasons (summer, rainy seasons) → Increase dosage
• Feed moisture content > 12% → Increase dosage
• Long storage cycle (> 3 months) → Increase dosage
• Favorable storage conditions (low-temperature and dry warehouse) → Adopt the lower limit of the dosage range

5.2 Uniform Mixing

To maximize its antifungal efficacy, sodium propionate must be evenly dispersed in feed. It is recommended to pre-mix the product with a small amount of carrier materials (such as corn flour or limestone powder) before full-batch mixing, so as to avoid uneven local concentration that may weaken the overall effect.

5.3 pH Environment Adaptation

Sodium propionate achieves optimal antifungal effects under acidic conditions (pH ≤ 5.0). If the feed formula contains alkaline raw materials such as limestone powder and dicalcium phosphate, the final pH of the finished feed should be monitored. The dosage shall be increased appropriately when necessary to ensure reliable mould prevention performance.

5.4 Compatibility with Other Preservatives

• It can be compounded with other organic acid preservatives such as calcium propionate and sorbic acid to broaden the antibacterial spectrum and reduce the dosage of single preservatives.
• For compound application, calculate the total dosage strictly to ensure compliance with relevant regulatory limits.

5.5 Regulatory Compliance

• EU: Approved for use as a feed additive for all terrestrial animals (re-approved in 2025)
• USA: Classified as a GRAS (Generally Recognized As Safe) substance by the FDA
• China: Listed in the official Catalogue of Feed Additives, permitted for targeted addition in livestock and poultry feeds

6. Packaging Specifications

A. 25 kg per bag, packed in paper-plastic composite bags or woven bags

B. Nylon ton bag packaging for bulk purchases

C. Custom packaging specifications available upon customer requests

7. Storage Requirements

• Store in a cool, dry and well-ventilated place, away from direct sunlight, high temperature and high humidity environments.
• Do not store or transport the product together with toxic chemicals or strong alkaline substances.
• Once opened, the product should be used as soon as possible and tightly resealed to prevent moisture absorption and deliquescence.