NATAMYCIN

CAS: 7681-93-8 FUMIGANT

Natamycin is a polyene antimycotic additive permitted as a food preservative to inhibit yeast and mold growth, evaluated by major regulators for specific surface applications.

What It Is

Natamycin is a naturally derived polyene antimycotic compound with a defined CAS of 7681-93-8 that functions principally as a mold and yeast inhibitor when applied to food surfaces. Classified technically here as a fumigant, natamycin is produced by certain species of _Streptomyces_ bacteria and has been used in food preservation systems to target spoilage organisms, particularly where fungal growth is a concern. This additive is known under other names including pimaricin and is referenced in regulatory frameworks such as 21 CFR 172.155 in the United States, which codifies its identity, purity, and allowable use in food products. Regulatory agencies globally refer to natamycin by these chemical and functional descriptors when discussing its safety and application, reflecting its role in limiting fungal spoilage while having minimal direct impact on the food matrix itself. Natamycin belongs to the larger class of polyene macrolides, antimicrobial substances that interact preferentially with ergosterol-like sterols in fungal cell membranes, inhibiting growth without permeabilizing bacterial cells. This selective action forms the basis of its technological use in food systems. While technically termed here as a fumigant based on the input instruction, in food usage contexts natamycin is typically applied as a surface coating or spray rather than through gas-phase fumigation, illustrating how its functional categorization in technical inputs may differ slightly from common industrial usage descriptions. Because it specifically inhibits mold and yeast proliferation on food surfaces, natamycin’s employment helps address spoilage pathways that can otherwise lead to product losses or quality degradation. Its inclusion in regulatory codices underscores its established applications and controlled conditions of use for food preservation.

How It Is Made

Natamycin is biosynthesized through the controlled fermentation of specific actinomycete bacteria, primarily _Streptomyces natalensis_ and related species. During production, these microorganisms are cultured under aerobic submerged fermentation, allowing them to produce the polyene macrolide antimicrobial compound as a secondary metabolite. After sufficient fermentation, the natamycin-containing broth is processed to separate the desired compound through broth extraction or by isolating it from the mycelial biomass, and then undergoes purification steps such as crystallization and drying to achieve a food-grade substance suitable for regulatory specifications. The purified natamycin must meet defined industry and regulatory criteria for identity and purity, which may vary by jurisdiction but often include limits on contaminants such as heavy metals and specifications for the active compound’s concentration. For example, in United States federal regulations, natamycin used in foods must conform to specified purity standards, including a defined percentage of the active compound and limits on arsenic and lead content in the additive formulation, as detailed in 21 CFR 172.155. These manufacturing and specification controls help ensure that the product applied to food surfaces performs consistently and is free from undesirable impurities that could affect quality or safety. Industrial fermentation of natamycin and its downstream refinement into a powdered or liquid form suitable for application involves standardized unit operations in biotechnology manufacturing, including upstream culture optimization, downstream filtration and extraction, and final formulation. These processes are managed to produce a stable additive that can be reliably used in surface treatment applications, where its low solubility in water concentrates the activity at the food surface rather than distributing it throughout the food, aligning with its intended technological function.

Why It Is Used In Food

Natamycin is used in food systems primarily to prevent or retard the growth of yeasts and molds that contribute to spoilage, particularly on surface-treated products such as cheeses and cured meats. Its technological role stems from its specific antifungal action, which makes it valuable for extending the shelf stability of foods that are not sterile and that may otherwise experience fungal growth during storage or distribution. Because yeast and mold spoilage can affect texture, appearance, and quality, preventing this growth helps maintain product integrity and reduces food losses. The use of natamycin is targeted to surface applications where fungal contamination risk is highest and where its physicochemical properties—especially low solubility in water—keep the active compound localized where it’s needed. Such surface treatment allows manufacturers to apply minimal active substance while achieving effective inhibition of spoilage organisms, which can be more efficient than other preservatives that require distribution throughout the food matrix. In regulatory contexts that permit its use, natamycin is applied at controlled levels on specific product categories under conditions that achieve the antifungal effect without altering the sensory properties of the food. This controlled use aligns with the technological goal of preserving product quality without introducing off-flavors or undesired changes, making natamycin a practical tool for addressing fungal spoilage in targeted food applications where mold and yeast growth present a recurring challenge.

Adi Example Calculation

To illustrate how an acceptable daily intake (ADI) is used, consider a hypothetical adult weighing 70 kg. If an expert committee has established an ADI range for an additive such as natamycin, the upper bound of this range represents the maximum amount that could be consumed daily over a lifetime without appreciable health risk under conditions of authorized use. Using this concept, multiply the ADI value by body weight to estimate the total milligrams of additive considered safe for daily intake. For example, if the ADI range’s upper bound corresponds to a certain milligram-per-kilogram value, multiplying that by 70 kg provides the total daily intake threshold for that individual. This calculation helps regulators and risk assessors compare dietary exposure estimates from multiple food sources with the ADI to determine whether typical consumption patterns remain within safety margins. It is important to note that such calculations are illustrative and based on average body weight assumptions; actual individual tolerances vary, and regulatory frameworks emphasize that ADIs are not targets for consumption but rather safety benchmarks for risk management. ADIs are used by authorities to evaluate whether permitted uses of an additive keep estimates of intake below levels that could raise health concerns.

Safety And Health Research

Safety evaluations of natamycin by major international expert bodies have focused on toxicological data, dietary exposure, and mechanisms of action relevant to consumer exposure. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) reviewed data on natamycin and established an acceptable daily intake range that reflects the levels at which lifetime daily intake is not expected to raise health concerns, based on available animal and exposure data. Such evaluations typically consider absorption, distribution, and excretion of the compound, and they assess toxicological endpoints including systemic effects in chronic studies to identify levels below which adverse effects are not observed. European food safety authorities have also examined natamycin’s safety in the context of specific use conditions, evaluating proposed surface treatment levels and considering whether these use levels present safety concerns for consumers. These reviews include assessments of whether its use could contribute to antimicrobial resistance issues and dietary exposure, concluding that specific authorized uses do not raise such concerns under regulatory conditions when applied within permitted levels. Overall, the body of safety research and regulatory assessment for natamycin emphasizes careful evaluation of toxicology and exposure, aligning permitted uses with conditions that maintain safety margins. This evidence-based approach supports regulatory decisions that allow natamycin for targeted applications while ensuring that consumers are not exposed to levels that would exceed established risk thresholds.

Regulatory Status Worldwide

In the United States, natamycin is regulated under specific provisions in the Code of Federal Regulations that permit its use as a food additive for direct addition to certain foods under defined conditions. Federal regulations in 21 CFR 172.155 authorize natamycin (pimaricin) with defined identity and purity specifications, and set maximum permissible application levels for use on cheese surfaces to inhibit fungal growth, illustrating a controlled regulatory status for this additive. This codified allowance means that natamycin is permitted in foods under the conditions outlined in the regulation, but such permissions are narrow and specific to certain use scenarios. In the European Union, natamycin is known under the additive code E235 and is authorized for use as a surface preservative on designated cheese and cured meat products with specified limits on concentration at the surface layer, reflecting conditions of authorized use under EU food additive law. These definitions and conditions derive from scientific assessments by EU food safety authorities, and they require compliance with specific food additive lists and maximum permitted levels to ensure that use falls within safety assessments performed by the relevant regulatory bodies. Internationally, the Joint FAO/WHO Expert Committee on Food Additives has evaluated natamycin and reaffirmed an acceptable daily intake based on toxicological data, which is used as a scientific basis in many jurisdictions’ risk assessments. While different countries may have varying lists of permitted uses or limits, regulatory frameworks commonly emphasize defined surface treatment applications, concentration limits, and compliance with purity specifications to ensure that the additive’s use accords with safety evaluations and legal requirements in each jurisdiction.

Taste And Functional Properties

Natamycin exhibits physical and functional properties that make it suitable for surface preservation applications without significantly affecting food taste or appearance. As a crystalline powder or suspension, it has minimal solubility in water and is largely inactive in the bulk food matrix, which contributes to its effectiveness as a surface treatment; this limited solubility helps confine its antifungal activity to the exterior layers where molds and yeasts typically initiate growth. Because of these properties, natamycin generally does not impart noticeable taste, odor, or color changes to treated foods, which is critical for maintaining the sensory quality that consumers expect in products like cheese. Functionally, natamycin interacts with ergosterol-like sterols in the membranes of fungal cells, inhibiting growth of yeasts and molds at low applied levels. This mode of action is distinct from that of common chemical preservatives that may act through pH-dependent mechanisms. For product developers, natamycin’s stability across a range of pH conditions and its localized action at the point of application support consistent antifungal performance without requiring high concentrations that could influence sensory attributes. Overall, the functional behavior of natamycin—localized antifungal activity, low solubility, and sensory neutrality—makes it a preferred choice for surface preservation of certain foods where minimizing yeast and mold growth is a priority, and where maintaining product taste and appearance is equally important.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is an estimate used by regulatory scientists to describe the amount of a food additive that can be consumed every day over a lifetime without appreciable health risk, expressed relative to body weight. Scientific committees review toxicological data from animal studies and other relevant information to identify levels that do not produce adverse effects, and apply uncertainty factors to account for differences between animals and humans as well as variability among individuals. This process results in an ADI that serves as a benchmark for safety evaluations of dietary exposure. For some additives, including natamycin, expert committees such as JECFA have reviewed extensive toxicological data and dietary exposure estimates to define an ADI range, which reflects the level of intake that is not expected to cause harm when the additive is used in accordance with authorized conditions. Regulatory bodies use the ADI as part of their risk assessment frameworks to determine whether proposed uses and resulting consumer exposure fall within safe limits. This conservative, science-based approach helps ensure that food additives do not pose undue risk to public health when used as intended.

Comparison With Similar Additives

Natamycin’s role as a surface-targeted antifungal preservative can be compared with other additives that serve to preserve food products by different mechanisms. For example, sorbic acid and its salts are widely used surface and bulk preservatives that inhibit a range of yeasts, molds, and some bacteria by lowering cellular activity through pH-dependent pathways. In contrast, natamycin’s mechanism involves direct interaction with fungal cell membranes, making it more specific to molds and yeasts and less influenced by food pH. This specificity can be advantageous in cheese and cured meat contexts where pH varies but surface fungal control is needed without broad-spectrum antimicrobial action. Another comparative example is nisin, a bacteriocin used predominantly to inhibit Gram-positive bacteria in certain foods such as processed cheese and canned products. While nisin targets bacterial cells, natamycin targets fungal cells, illustrating how different preservatives can be selected based on the spoilage organisms of concern. Both additives are regulated with defined conditions of use and concentration limits reflecting safety evaluations. Comparing these preservatives highlights how formulation strategies align with the additive’s spectrum of activity and the food product’s preservation needs, allowing manufacturers to choose agents that best match the desired microbial control without compromising sensory attributes.

Common Food Applications Narrative

Natamycin is widely used in food preservation to help control spoilage caused by molds and yeasts on the surfaces of specific products. Because many dairy foods and cured meats can develop surface fungal growth during ripening, storage, or distribution, manufacturers have long applied natamycin as a surface agent to address this common challenge. In cheeses such as semi-hard and semi-soft varieties, surface treatment with natamycin helps maintain appearance and extend shelf life without impacting the interior texture or flavor, which supports both retail quality and consumer satisfaction. Beyond cheese, cured and dried meat products that are susceptible to unwanted fungal development on casings or external surfaces can also benefit from targeted natamycin application, which allows producers to meet quality expectations for visual and microbiological stability. By focusing natamycin’s activity where mold growth commonly initiates, these applications achieve their preservation goals without excessive use of broader-spectrum preservatives that might influence product character. In each of these applications, the use of natamycin aligns with the technological need to manage spoilage organisms while preserving the sensory qualities that define these products. This targeted use of an antifungal additive supports food industry efforts to reduce waste, maintain quality over shelf life, and meet regulatory conditions that permit such functional surface treatments, illustrating how natamycin contributes to practical preservation strategies in surface-sensitive food categories.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.155

EFSA

  • Notes: Specific numerical ADI not quoted directly on the provided EFSA opinion link
  • Approved: True
  • E Number: E235

JECFA

  • Year: 2024
  • Ins Number: 235
  • Adi Display: 0-0.3 mg/kg bw
  • Adi Mg Per Kg: 0.3

Sources

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