O-PHENYLPHENOL

CAS: 90-43-7 ANTIMICROBIAL AGENT, SURFACE-ACTIVE AGENT

O-Phenylphenol is a synthetic antimicrobial compound with surfactant properties used primarily as a preservative and post-harvest treatment agent evaluated by international safety bodies.

What It Is

O-Phenylphenol (CAS 90-43-7) is a synthetic organic compound of the hydroxybiphenyl chemical class. It is characterized by two joined benzene rings with a single hydroxy functional group, making it a phenolic antimicrobial and surface-active agent. Known under multiple synonyms, this compound has historical use in food-related contexts such as surface preservation of citrus and other fruits. It functions by interacting with microbial cell structures, contributing to its antimicrobial activity in food contact and industrial applications. Its classification reflects this dual role as an antimicrobial agent and as a surface-active agent in formulations. Although originally evaluated as a food additive preservative under international food safety assessments, contemporary regulatory practice varies geographically. The compound’s inclusion in specific regulations often pertains to defined technical conditions rather than general food ingredient status, and its use and safety are managed accordingly. Many regulatory frameworks treat it as an additive with specific intended uses, requiring defined conditions for safe application and monitoring.

How It Is Made

O-Phenylphenol is synthesized through organic chemical processes involving the condensation and dehydrogenation of precursor molecules. Classical industrial routes include partial oxidation, condensation of cyclohexanone derivatives followed by dehydrogenation, and recovery from phenol production residues via sulfonation and distillation methods. These processes yield the characteristic hydroxybiphenyl structure, and subsequent purification steps ensure high purity suitable for regulatory and technical uses. The finished product is typically obtained in crystalline form with high chemical purity according to specification monographs maintained by bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA). These specifications define acceptable levels of impurities and structural identity tests to ensure consistent performance in intended applications. Purification and characterization steps are essential for controlling product quality and mitigating unwanted byproducts.

Why It Is Used In Food

O-Phenylphenol has been used in food-related contexts primarily for its antimicrobial properties. In post-harvest handling of certain fruits, its application helps reduce mold and microbial spoilage by limiting the growth of microbes on treated surfaces. It has also been evaluated for use in food contact materials where antimicrobial action at the surface level may contribute to product stability during storage and distribution. In these contexts, the compound’s mode of action targets microbial cells at susceptible points, reducing spoilage risks. Regulatory allowances for such uses typically come with defined conditions that specify the form, concentration, and application methods under which O-Phenylphenol can be applied to food or food contact surfaces. This reflects a balance between the intended technological effect and safety considerations, which include controlling residues that may remain on treated surfaces. Because of these controlled and specific use scenarios, O-Phenylphenol is not broadly used throughout all food categories but is managed within narrower technical niches.

Adi Example Calculation

To illustrate how an ADI might be interpreted, consider a hypothetical adult body weight of 70 kg. If an established ADI range were specified for O-Phenylphenol, multiply the upper bound of that range by the body weight to estimate the total amount that would be considered not to pose appreciable risk over a lifetime. For example, if an ADI upper bound of X mg/kg body weight were allocated, a 70 kg adult’s allowable daily exposure would be 70 times X mg per day. This type of calculation assists in regulatory risk assessments but is purely illustrative and is not a personalized recommendation.

Safety And Health Research

Safety evaluations of O-Phenylphenol have been conducted over multiple decades, particularly in the context of its antimicrobial use on food contact surfaces and post-harvest treatments. Toxicological studies referenced in international evaluations form the basis for understanding its hazard profile, including studies on acute toxicity and chronic exposure in laboratory animals. Regulators examine such data to determine whether exposure under specified conditions could pose risks, and this evaluation informs safety assessments and any acceptable daily intake parameters. Research published in chemical and toxicology literature has examined metabolite profiles and potential effects in experimental models, though human data remain limited. Regulatory safety frameworks focus on ensuring that any residues resulting from intended uses remain within levels considered acceptable based on risk assessments. These frameworks also account for manufacturing purity and impurities that might influence safety. Because O-Phenylphenol is not widely used in direct food ingredients, exposure from treated surfaces or food contact materials typically represents the primary pathway for evaluation in food safety assessments rather than dietary consumption as a direct ingredient.

Regulatory Status Worldwide

O-Phenylphenol has been evaluated by international food safety bodies and appears in regulatory references related to food contact and antimicrobial uses. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated this compound and allocated an ADI range for its use under conditions examined in the 1999 evaluation, reflecting historical assessments of safety when applied in specified contexts. The JECFA number and INS designation reflect its inclusion in international food additive frameworks where applicable. Source documentation details its functional class and specifications established in these evaluations. (世界卫生组织应用) At the national level, regulatory frameworks such as the U.S. Code of Federal Regulations include references to specific sections where substances used in food contact materials and processing aids are listed. However, the presence of O-Phenylphenol in regulatory citations does not by itself constitute unrestricted approval for all food uses. Many jurisdictions treat its antimicrobial uses in food contact or surface applications as subject to defined technical conditions and limitations rather than general broad approval. This approach reflects safety frameworks that require contextual justification for specific applications.

Taste And Functional Properties

From a sensory perspective, O-Phenylphenol itself does not contribute desirable flavor attributes when used as an additive or surface treatment; its primary role is functional rather than organoleptic. The compound is a solid at room temperature with phenolic characteristics, and its direct contribution to taste in food matrices is generally considered neutral or undesirable when present. Its antimicrobial efficacy rather than taste modulation underpins its utility. Functionally, it behaves as a surface-active agent in formulations, enhancing coverage on treated surfaces and facilitating interaction with microbial cells. Its activity can be influenced by pH and formulation context but is valued for its broad-spectrum activity against fungi and certain bacteria on treated surfaces. Solubility characteristics support use in aqueous or solvent-based preparations designed for surface application rather than direct incorporation into diverse food matrices.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is a risk management tool used by international regulatory bodies to describe an estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable health risk. In O-Phenylphenol’s case, an ADI range was allocated in historical JECFA evaluations, reflecting the concentrations examined in toxicological studies and the application contexts considered. The ADI range provides a conservative safety threshold for regulatory assessment when residues may arise from surface applications or contact scenarios. (世界卫生组织应用) It is important to note that the ADI does not represent a recommended intake but a boundary for regulatory risk assessment. When a substance has an established ADI, regulatory authorities use this parameter to determine acceptable exposure levels from all possible sources under intended use conditions.

Comparison With Similar Additives

O-Phenylphenol can be compared with other antimicrobial additives such as sodium benzoate, potassium sorbate, and sorbic acid, which are more widely recognized for controlling spoilage in acidic foods. Unlike these other agents, which are commonly used directly in food formulations at defined concentrations to inhibit yeast and mold, O-Phenylphenol’s functional applications often focus on surface or contact scenarios where microbial control is needed. While all of these substances aim to extend shelf life by limiting microbial growth, their chemistry, regulatory status, and typical use patterns differ significantly. Whereas common preservatives such as sorbates are generally incorporated into the food matrix, O-Phenylphenol use is more specialized, emphasizing specific surface applications and engineered contexts where its antimicrobial properties support product quality.

Common Food Applications Narrative

Applications of O-Phenylphenol in food-related contexts have historically centered on its ability to reduce microbial spoilage in post-harvest situations. For example, it has been used on the surfaces of harvested citrus fruits and other produce to help manage mold and fungal growth during storage and distribution. In these settings, the compound is applied to surfaces where microbes may proliferate, mitigating spoilage without becoming a substantive ingredient in the food itself. Its purpose is to maintain the quality of produce between harvest and processing or retail. Outside of produce, the compound’s role extends to specific food contact materials where antimicrobial surface action may be beneficial. For example, in select packaging scenarios or equipment surfaces, formulations incorporating O-Phenylphenol can contribute to microbial control as part of a broader hygienic strategy. These applications reflect regulatory and technological frameworks in which the compound’s surface-active and antimicrobial properties are leveraged in a targeted manner rather than as a broad-spectrum preservative across all food categories. In modern practice, such uses are subject to specific regulatory authorizations and technical conditions to ensure safety and efficacy.

Safety & Regulations

FDA

  • Notes: Specific FDA approval status for general food additive use could not be confirmed; listed references include food contact sections but do not represent broad approval.

EFSA

  • Notes: EFSA numeric ADI values specific to food additive use were not found in authoritative sources.
  • E Number: 231

JECFA

  • Year: 1999
  • Notes: JECFA allocated an ADI range in historical evaluations; upper bound presented.
  • Ins Number: 231
  • Adi Display: 0-0.4 mg/kg bw

Sources

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