Research progress on the food preservation effects exploiting the antifungal properties of thymol

Abstract

Thymol is a major monoterpene compound from Lamiaceae plants. Thymol exhibits antifungal, antioxidant, and anti-inflammatory properties. Over the past few years, extensive research has underscored the pivotal role of thymol in delaying postharvest senescence in fruits and vegetables, suppressing fungal growth in meat products, and enhancing the shelf life of meat and processed foods. This review systematically summarized the antifungal characteristics and preservation mechanisms of thymol, with a particular emphasis on its applications in food preservation in recent years. This study provides a systematic review of the antifungal properties of thymol and its underlying mechanisms in the preservation of fruits, vegetables, and meat. It offers a comprehensive analysis of the potential pathways through which thymol contributes to maintaining food quality and prolonging shelf life. The paper thoroughly elucidates the beneficial effects of thymol on food preservation, emphasizing its specific mechanisms in inhibiting fungal proliferation, enhancing food quality, and reducing nutrient degradation. Finally, the article summarized the current state of research on thymol, evaluates its future application potential, and identifies several key areas that warrant further exploration in this field.

Highlights

• •Thymol treatment preserves fruit flavor, inhibits pathogens, and boosts disease resistance.
• •Thymol treatments include membrane treatment, fumigation and direct addition.
• •New insights into thymol in fruit and vegetable preservation.

1. Introduction

Thymol (2-isopropyl-5-methylphenol) is a major monoterpene phenolic compound primarily isolated from plants belonging to the Lamiaceae family, such as thymus, Origanum, and Mentha species. It is also found in other plant families, including Verbenaceae, Scrophulariaceae, Ranunculaceae, and Apiaceae (Alagawany, Farag, Abdelnour, & Elnesr, 2021). Thyme essential oil contains an active component that demonstrates a range of pharmacological properties recognized in traditional medicine. These properties include expectorant, antispasmodic, antifungal, antioxidant, carminative, diaphoretic, anti-rheumatic, antihypertensive, and sedative effects (Kianersi, Pour-Aboughadareh, Majdi, & Poczai, 2021). Thymol and other essential oils exhibit sedative and anesthetic effects on fish, which may be utilized in aquaculture and research settings for stress reduction and humane handling (Aydın & Barbas, 2020). Thymol is widely utilized across the pharmaceutical, food, and cosmetic sectors (Xiang, Wang, & Sun, 2021). As a bioactive compound incorporated in numerous medicinal preparations, thymol exhibits significant inhibitory effects on tumor cell proliferation, alongside the ability to induce apoptosis and cause cell cycle arrest (Zeng et al., 2020). Furthermore, thymol's antioxidant properties render it an effective preservative and antioxidant agent within the cosmetics industry (Kirkova et al., 2025). According to The Food and Agriculture Organization (FAO) of the United Nations, the widening gap between supply and demand is driven by population growth and increasing food loss and waste (Zhang et al., 2024). While a wide variety of preservatives are currently employed in food preservation, chemical preservatives frequently provoke safety concerns and worries about potential chemical residues. Considering the growing awareness surrounding food safety, consumers are increasingly inclined to select preservatives that are deemed safe, non-polluting, and environmentally sustainable for food preservation. The application of natural antifungal agents in this context has garnered considerable attention, with thymol being recognized as a particularly advantageous candidate owing to its favorable safety profile, environmental compatibility, biodegradability, and potent antioxidant and antifungal properties (Wang, Li, Liu, & Jiang, 2025).

The European Commission has officially registered thymol, along with other components of thyme essential oil such as carvacrol, citral, and eugenol, as flavoring agents in food. This registration aligns with the classification of these substances as‘generally recognized as safe’ (GRAS) or approved food additives by the United States Food and Drug Administration (FDA) (Kalyvianaki et al., 2020). The biosynthesis of thymol initiates with isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which serve as universal precursors for all terpenoids. These precursors are synthesized via two distinct metabolic pathways: the methylerythritol phosphate (MEP) pathway and the mevalonate (MVA) pathway. The MEP pathway occurs in plant chloroplasts and begins with pyruvate and glyceraldehyde-3-phosphate, undergoing a series of enzymatic reactions catalyzed by key enzymes such as 1-deoxy-D-xylulose-5-phosphate synthase (DXPS) and 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), ultimately yielding IPP and DMAPP. In most plant species, the MEP pathway constitutes the primary source of precursors for monoterpenoids, including thymol. In contrast, the MVA pathway operates in the cytoplasm and initiates with acetyl-CoA, progressing through enzymatic steps involving key enzymes such as hydroxymethylglutaryl-CoA reductase (HMGR) to generate IPP, which is subsequently converted to DMAPP by isomerases. Although the MVA pathway may complement the MEP pathway in certain plant species, its contribution to monoterpene biosynthesis is generally limited. The subsequent formation of the monoterpene skeleton involves the condensation of IPP and DMAPP under the catalysis of geranyl pyrophosphate synthase (GPPS), resulting in the production of geranyl pyrophosphate (GPP), the direct precursor for monoterpenoid biosynthesis. This is followed by the cyclization of GPP, catalyzed by terpene synthases (TPS), leading to the formation of γ-terpinene, a crucial intermediate in thymol biosynthesis. Through a series of downstream reactions, including the dehydration of cyclohexadienol and keto-enol tautomerism, a stable aromatic ring structure is formed, culminating in the final synthesis of thymol (Kianersi et al., 2021; Krause et al., 2021; Mohammadi, Talebi, Ahmadnasab, & Mollahassanzadeh, 2023; Zhang et al., 2024).

Prior research has demonstrated that thymol has the capacity to disrupt the lipid bilayer of cellular membranes, which may enhance membrane permeability and lead to the mortality of fungal cells, thereby exhibiting antifungal properties (Zhang, Ma, Du, Chen, & Sun, 2019). Numerous researchers have investigated the application of thymol in preserving fruits, vegetables, and meat products, including longan (Khan et al., 2021), blueberries (Xie et al., 2025), chili peppers (Akbari, Radi, Hosseinifarahi, & Amiri, 2024), potatoes (Liu et al., 2022), and pork (Liu & Liu, 2020). Thymol has been shown to effectively inhibit fungal growth while enhancing the sensory quality of fruits and vegetables. Extensive research indicates that thymol, as a natural preservative, holds significant potential for broad applications.

This article provided a comprehensive review of the natural distribution of thymol, its synthetic pathways, and the mechanisms through which thymol exerted its preservative effects on fruits, vegetables, and meat. Additionally, it examines the preservation effects of thymol on various types of fruits, vegetables, and meats. Thymol treatment demonstrated notable antifungal properties and played a critical role in preserving the postharvest quality of fruits. The utilization of carvacrol, a natural plant-derived essential oil, presented substantial potential for improving the postharvest preservation of both fruits and vegetables. This review offered an in-depth analysis of thymol's efficacy in maintaining the quality of harvested produce, alongside a forward-looking evaluation of its prospective applications, thereby providing meaningful guidance for future research endeavors.

2. Antimicrobial properties

Thymol is a major component of thyme essential oil. As demonstrated in the extant literature, thymol has been shown to possess potent antioxidant, anti-inflammatory, and antifungal properties (Hepokur et al., 2020; Saoulajan et al., 2022). In addition to its antifungal properties and established biological safety, thymol is a prevalent preservative in food processing (Yu, Chin, & Paik, 2021). The mechanism of action of this compound involves the inhibition of both Gram-positive and Gram-negative bacteria, including Staphylococcus aureus, Escherichia coli, Salmonella, and Candida albicans. It is evident that due to its physiological activities, thymol possesses excellent antifungal and antioxidant capabilities. The antibacterial mechanism of thymol has been the subject of extensive research, which has revealed its ability to achieve effective preservation by inhibiting microbial growth. Thymol destroys the cell wall structure of Staphylococcus aureus and shows strong fungal ability (Zhang et al., 2023). Studies on Enterobacter sakazakii indicate that thymol at 1.25 mg/mL induces membrane damage, reducing intracellular ATP levels to less than 20 % of the control group (Tian et al., 2021). Thymol significantly decreases the content of 12-methyltetradecanoic acid in Staphylococcus aureus membranes (from 22.4 % to 7.9 %), affecting membrane fluidity. Atomic force microscopy reveals that thymol binds to fungal DNA, thereby destabilizing its secondary structure and potentially interfering with replication and transcription. In addition, thymol has been shown to inhibit fungal energy metabolism by disrupting ergosterol synthesis and mitochondrial function, leading to reactive oxygen species (ROS) accumulation and hyphal death (Kong et al., 2021; Zhang et al., 2019). Additionally, thymol indirectly suppresses pathogenic bacteria proliferation by modulating gut microbiota (e.g., increasing Bifidobacterium pseudolongum abundance), promoting secondary bile acid production (e.g., HDCA), and activating the cGMP-PKG-mTORC1 pathway (Zhang et al., 2024). The combined application of carvacrol and polymyxin demonstrates a synergistic bactericidal activity against polymyxin-resistant Gram-negative bacteria, including Pseudomonas aeruginosa. This synergism is mediated through multiple mechanisms: disruption of the bacterial outer membrane integrity, enhancement of polymyxin penetration, and induction of intracellular acidification via inhibition of H⁺-ATPase. These effects collectively result in intracellular ATP depletion and DNA leakage, contributing to bacterial cell death (Yao et al., 2022).

Thymol interacts with the lipid bilayer of bacterial cell membranes via hydrophobic interactions, thereby compromising the structural integrity of the membrane (Tian et al., 2020). This interaction elicits several physiological responses, including intracellular ATP leakage, membrane potential depolarization, and a reduction in intracellular pH (Fig. 1). In pathogenic fungi, thymol disrupts both the cell membrane and cell wall, causing membrane rupture and subsequent leakage of cellular contents (Fig. 1). As a result, hyphal growth is inhibited, pathogen mortality is increased, and the overall shelf life is prolonged (Aslam et al., 2025).

Fig. 1.

Mechanism of thymol's antimicrobial action.

3. Thymol's preservation mechanism

3.1. Application in fruits and vegetables preservation

3.1.1. Fruits

It is well established that fruits experience detrimental alterations in color, flavor, texture, and nutritional quality throughout storage and distribution. These changes are frequently intensified by infestations of diseases and pests, which significantly diminish the overall quality of the fruit. Research conducted by Shah et al. (2021) and Zhang, Pan, Jiang, and Zhang (2024) has demonstrated that thymol effectively inhibits the proliferation of pathogenic fungi and delays fruit senescence, as further supported by the findings of Olmedo et al. (2025) and Chillet, Minier, Hoarau, and Meile (2019). Synthetic fungicides are extensively employed during both pre-harvest and post-harvest stages to manage plant diseases. Nevertheless, prolonged and intensive use of these chemical agents may result in the development of resistant fungal strains, accumulation of chemical residues, and environmental contamination (Ding et al., 2023). Furthermore, thymol enhances antioxidant capacity, reduces respiration rates, inhibits the degradation of cell membranes and cell walls (Ding et al., 2023; Lu et al., 2021), and prevents nutrient loss (Chen et al., 2021). In the management of Aspergillus niger, it was observed that thymol concentrations ranging from 10 to 30 mg/L exhibited greater efficacy compared to higher concentrations of 40 to 50 mg/L. Furthermore, treatment of blueberry peel with thymol resulted in a significant increase in the activity of enzymes associated with disease resistance (Ding et al., 2023). Various methods exist for preserving fruits with thymol, with one of the most common approaches being its combination with other film-forming agents to create edible coatings. For example, Huang et al. (2023) employed an edible coating embedded with thymol microcapsules on blueberries, effectively preserving fruit firmness and investigating the impact of the thymol-enriched coating on the cell wall at both the genetic and transcriptional levels. Microscopic analyses demonstrated that this treatment maintained pectin content, thereby prolonging the shelf life of the blueberries. In a similar vein, Ranjbar, Ramezanian, Shekarforoush, Niakousari, and Eshghi (2022) reported that thymol suppressed the proliferation of principal spoilage fungi in pomegranates, specifically Aspergillus niger and Penicillium commune, by diminishing cellulase and pectinase activities, which consequently reduced fruit decay. Together, these studies highlight the critical role of thymol in inhibiting fungal growth as well as in preserving the structural integrity and nutritional quality of fruit products.

In addition to the widely utilized membrane-based preservation techniques, thymol fumigation has emerged as a potent method for mitigating postharvest diseases in fruits. Olmedo et al. (2023) employed thymol vapor to effectively manage postharvest rot in grapefruits caused by Penicillium digitatum and Phomopsis cacaoi, while simultaneously reducing weight loss. Furthermore, thymol vapor treatment has been demonstrated to possess antifungal properties and to enhance antioxidant capacity. Specifically, thymol treatment significantly maintained the firmness, total phenolic content, and antioxidant activity of cherries. It also augmented the enzymatic activities of guaiacol peroxidase (GPX) and catalase (CAT) during cold storage, leading to a reduction in the accumulation of reactive oxygen species (ROS), such as H₂O₂ and O₂^·-, thereby contributing to the preservation of cherry quality throughout the postharvest storage period (ValizadehKaji & Fakhri, 2023). In a similar vein, Ranjbar, Ramezanian, and Niakousari (2024) reported that thymol treatment improved the antioxidant potential of ready-to-eat pomegranate seeds. Fig. 2 illustrates the various metabolic pathways influenced by thymol. Notably, thymol not only exhibits significant antifungal activity but, when applied at an optimal concentration, can also effectively preserve the flavor quality of fruits. Ding et al. (2024) demonstrated that a coating containing thymol microcapsules enhances the flavor profile of blueberries while preventing cell membrane damage. Additionally, Zhang et al. (2025) investigated flavor alterations in strawberries using HS-GC-IMS and found that when thymol concentration exceeded 20 mL, the levels of 2-butanone-D, a crucial compound for strawberry aroma, significantly declined. This indicates that excessive thymol may negatively impact fruit flavor, whereas an optimal dosage can better preserve both flavor and nutritional quality. These findings are consistent with the research conducted by Min et al. (2021), Wu, Liu, He, Liu, and Shao (2023), and Ansarifar and Moradinezhad (2022). In addition, scientists have demonstrated that thymol exhibits excellent disease control effects on citrus (Zhang, Tan, et al., 2023; Pinto et al., 2021), kiwifruit (Salmas et al., 2022), and plums (Jenneker et al., 2024). Table 1 provides a summary of the impacts of thymol treatment on fruit quality.

Fig. 2.

The mechanism of thymol in maintaining the post-harvest quality of fruits and vegetables and controlling pathogenic fungi.

Table 1.

The effects of thymol on fruit preservation.

Application	Method	Quality	Reference
Citrus	γ-Cyclodextrin encapsulated thymol	P. digitatum↓	Zhang, Tan, et al. (2023)
	Red thyme oil (Thymus vulgaris L.) vapours	AsA↑, sensory↑, penicillium↓	Pinto et al. (2021)
	Wax coating	Firmness↑，decay rate↓	Martínez-Hernández, Navarro-Martínez, and López-Gómez (2025)
Kinnow	Citral-thymol based synergistic shellac coating	PME↓, Cx↓, AsA↑, DPPH↑, TPC↑	Tandon, Kalia, Bhardwaj, and Mahajan (2024)
Banana	Zein nanoencapsulation	Anthracnose↓	Punelas-Villanueva et al. (2024)
Melon	pH and Amylase Dual Stimulation Responsive Electrostatic Spinning Membranes	Phytophthora infiltrata↓	Du et al. (2023)
Longan	Fumigation with Thymol	BI↓, DI↓, PPO↓, TPC↑, TFC↑	Khan et al. (2021)
Blueberry	Konjac Glucan/Low Acyl Gellan Coating with Thymol Microcapsules	Anthocyanin↓, decay rate↓	Xie et al. (2025)
	Konjac glucomannan/low-acyl gellan gum edible coating containing thymol microcapsule	PG↓, PE↓, PL↓, β-Gal↓, α-Man↓, α-Af↓, Xth↓, β-Xyl↓, Cx↓, β-Glu↓	Huang et al. (2023)
	Thymol microcapsules	Botrytis cinerea (B. cinerea) ↓	Olmedo et al. (2025)
	Thymol aqueous solution	Firmness↑, TSS↑, A. niger↓	Ding et al. (2023)
	Antimicrobial soybean protein isolate film incorporating diatomite/thymol	Weight loss↓, decay rate↓, TA↑, TSS↑, firmness↑	Lu et al. (2021)
	Konjac glucan-nan/low-acyl gellan edible coatings loaded thymol-β-cyclodextrin microcapsules	Spoilage rate↓, weight loss↓, respiration rate↓, flavor↑	Ding et al. (2024)
Kiwi	Novel Edible Active Coatings Based on Rich Thymol Halloysite Nanostructures and Chitosan/Polyvinyl Alcohol Gels	Escherichia coli (E. coli) ↓, Salmonella enterica (S. enterica)↓, Salmonella aureus (S. aureus)↓, Listeria monocytogenes (L. monocytogenes)↓	Salmas et al. (2022)
Chestnut	Thymol loaded chitosan nanoparticle	Amylase↓, TSS↑	Guo et al. (2022b)
Plums	Gum Arabic-incorporated thymol/salicylic acid composite coatings	Grey mould↓, brown rot↓	Jenneker et al. (2024)
Strawberry	Antimicrobial pullulan packaging materials embedded with starch/thymol nanoemulsion via dynamic high-pressure micro-fluidization	Weight loss↓，TA↑，TSS↑，firmness↑, flavor↑	Zhang et al. (2025)
	Electrospun pullulan/PVA nanofibers integrated with thymol-loaded porphyrin metal organic framework	Salmonella aureus (S. aureus)↓, Escherichia coli (E. coli)↓	Min et al. (2021)
	Edible food packaging gelatin/zein based nanofiber film	Escherichia coli (E. coli)↓, Salmonella aureus (S. aureus)↓ and Listeria monocytogenes↓	Wu et al. (2023)
	Preservative Film	Botrytis cinerea (B. cinerea)↓, Colletotrichum gloeosporioides (C. gloeosporioides)↓	Zhang, Pan, et al. (2024)
Apple	Sodium alginate-based films incorporated with thymol	AsA↑, L↑, Weight loss↓	Chen et al. (2021)
Mango	1% chitosan plus 400 μL l-1 thyme oil	Colletotrichum gloeosporioides (C. gloeosporioides)↓	Shah et al. (2021)
	Thymol/terpene solvent	Colletotrichum gloeosporioides (C. gloeosporioides)↓, Weight loss↓	Chillet et al. (2019)
Pomegranate	Thymol	PG↓, Cx↓	Ranjbar et al. (2022)
	Thymol and MAP	Color↑, phenolic acid↑	Ranjbar et al. (2024)
Grapefruit	Thymol Vapor	Penicillium digitatum (P. digitatum)↓ and Lasiodiplodia theobromae(L. theobromae)↓	Olmedo et al. (2023)

In conclusion, thymol not only possesses excellent antifungal properties but also helps maintain the integrity of cell walls and membranes, enhances antioxidant capacity, and preserves sensory flavor quality. With its broad-spectrum antifungal activity, thymol protects fruits from pathogen invasion, extends shelf life, and reduces spoilage and deterioration.

3.1.2. Vegetables

Table 2 outlines the primary effects of thymol on vegetables, highlighting its role in mitigating common diseases and improving sensory quality during storage. Vegetables are particularly susceptible to diseases under typical conditions, often manifesting symptoms such as wilting and yellowing. Recent studies have demonstrated that thymol effectively inhibits browning in vegetables, enhances antioxidant capacity, and strengthens antifungal activity during preservation. Given the vulnerability of fresh fruits and vegetables to fungal infections during storage, thymol application significantly enhances antifungal efficacy against prevalent pathogens, including Aspergillus flavus (Poosarla et al., 2024), Phytophthora capsici (Arora, Sharma, & Sharma, 2023), and Botrytis cinerea (Álvarez-Hernández, Martínez-Hernández, Castillejo, Martínez, & Artés-Hernández, 2021). Zhang et al. (2023) reported that an edible coating containing thymol can control postharvest anthracnose in okra by modulating lignin biosynthesis pathways and phenylpropanoid metabolism, resulting in increased total phenolic and flavonoid contents. Furthermore, thymol has been found to disrupt the integrity of fungal cell membranes and cell walls, causing cellular rupture and enhancing microbial resistance in okra. A concentration of 30 mg/L thymol has been demonstrated to significantly prolong the shelf life of onions by effectively mitigating fungal infections during low-temperature storage, with a notable inhibitory effect on the incidence of grey mould disease (Ji, Shankar, Royon, Salmieri, & Lacroix, 2021). Furthermore, at a minimum inhibitory concentration of 1.25 mg/mL, thymol induces depolarization of the cell membrane, reduces intracellular ATP levels, and lowers intracellular pH (pHi) in Enterobacter sakazakii BNCC 186088 cells. These effects suggest membrane disruption and disturbance of intracellular homeostasis, thereby effectively suppressing the growth and proliferation of this bacterium (Tian et al., 2021).

Table 2.

Effect of thymol on the preservation of vegetables.

Application	Method	Quality	Reference
Tomato	Coating of polyhydroxybutyrate-carboxymethylcellulose-pectin-thymol conjugates	Firmness↑, Lycopene↑，decay rate↓	Poosarla et al. (2024)
	An antifungal active packaging containing thymol and an ethylene scavenger	Staphylococcus greyi↓	Álvarez-Hernández et al. (2021)
	Thymol by Cyclodextrin Metal-Organic Frameworks	Decay index↓, weight loss↓, TSS↑, firmness↑	Li et al. (2022)
Okra	Thymol Edible Coating	Anthracnose↓	Zhang et al. (2022)
	Thymol Edible Coating	Firmness↑, PAL↑, 4CL↑, C4H↑, TPC↑	Zhang, Wang, et al. (2023)
Onion	Fumigation with Thymol	A. niger↓, Botrytis aclada (B. aclada)↓	Ji, Kim, Keum, and Chun (2018)
Pepper	Ultrasound combined with thymol	Respiratory strength↓，decay rate↓，TPC↑, TFC↑，DPPH↑	Akbari et al. (2024)
	Thyme essential oil and aqueous extract of licorice	Candida↓，P. aphanidermatum↓	Arora et al. (2023)
Potato	Thymol	dry rot↓，Fusarium oxysporum↓	Liu et al. (2022)
Lettuce	Edible coatings containing thymol	AsA↑，chlorophyll↑	Liu et al. (2024)
Carrot	Edible Coatings Incorporated with Free or Microencapsulated Thyme Essential Oil	TPC↑, TFC↑, DPPH↑, ABTS↑	Viacava et al. (2022)
	Nanocomposite alginate-based edible coatings containing thymol-nanoemulsion and/or thymol-loaded nanostructured lipid carriers	Molds↓, yeasts↓, lactic acid fungi↓	Talesh et al. (2024)
Basil	Edible coating with thyme volatile oil	Lipid peroxidation↓, weight loss↓, CAT↑, SOD↑	Hassan et al. (2021)

In their study, Hassan, Ali, Mostafa, and Mazrou (2021) employed thyme essential oil which contains 43.9 % thymol, incorporated into chitosan (CS) and chitosan nanoparticles (CSNP) for the preservation of basil leaves. This approach resulted in improved preservation outcomes, enhanced activity of antioxidant enzymes, and the maintenance of cell membrane integrity.

Thymol has been demonstrated to be an effective antimicrobial agent in the preservation of fresh-cut vegetables. Viacava, Cenci, and Ansorena (2022) reported that edible coatings incorporating thyme essential oil significantly reduced microbial populations on fresh-cut carrot slices, concurrently enhancing their antioxidant capacity, maintaining the vibrant coloration of the carrots, and improving sensory attributes. Comparable outcomes were observed by Talesh, Amiri, Radi, and Hosseinifarahi (2024). Furthermore, Liu et al. (2024) applied thymol-infused edible coatings to fresh-cut lettuce, achieving notable success in preserving sensory quality and inhibiting microbial proliferation, while also maintaining elevated levels of ascorbic acid and chlorophyll. Collectively, these studies indicate that thymol not only enhances antioxidant properties but also mitigates enzymatic browning and preserves overall quality through metabolic regulation, underscoring its broad potential for application in fresh produce preservation.

3.2. Meat preservation

Meat is especially susceptible to contamination by microorganisms and pathogens, resulting in significant economic losses and potential health risks. As a nutrient-dense food, it offers high-quality protein, essential minerals, complex B vitamins, and amino acids. These nutrients collectively facilitate the growth and multiplication of spoilage microorganisms as well as common foodborne pathogens (Ji et al., 2021). Bacteria such as Salmonella, E. coli, S. aureus, as well as molds, yeasts, Lactobacillus species, and Pseudomonas species, are closely associated with meat spoilage (Liu & Liu, 2020). Recent studies have demonstrated that thymol exhibits broad-spectrum antibacterial properties and effectively preserves various types of meat, including pork (Giannakas et al., 2023), chicken (Wang et al., 2022; Borhani, Amiri, & Radi, 2024), lamb, and beef (Dai et al., 2022; Karam, Chehab, Osaili, & Savvaidis, 2020); Mohajer et al., 2021), by inhibiting the growth of harmful microorganisms. Wang et al. (2023) coated pork with a thymol-containing film. After 11 days of storage, the TBARS value of pork coated with TH&CA@PC-PZ-Z film was only 0.33 ± 0.03 mg/kg, whereas the control group exceeded the 0.5 mg/kg threshold by day 9. The TH&CA@PC-PZ-Z film demonstrated excellent water retention and antioxidant capabilities, effectively suppressing bacteria proliferation in pork and mitigating lipid peroxidation in cell membranes. Furthermore, its safety was validated through animal experiments. Consistent results were also reported by Salmas et al. (2023). Furthermore, the analysis of membrane potential, intracellular ATP concentration, and intracellular pH, combined with observations using confocal laser scanning microscopy (CLSM) and field emission gun scanning electron microscopy (FEGSEM), demonstrated that thymol at a concentration of 1.25 mg/mL significantly induced membrane damage in Enterobacter sakazakii BNCC 186088 and effectively inhibited its growth and development (Tian et al., 2021). In aquatic product applications, Chen et al. (2022) used a double-layer film containing thymol to coat fish, effectively suppressing Pseudomonas growth and reducing the increase in total volatile basic nitrogen (TVB-N) during storage. The blank group had a TVB-N value of 25.76 mg N/100 g, while the thymol double-layer film group had a value of 20.05 mg N/100 g. The PLA/FGSA-Ty film was the most effective in preventing the rise of TVB-N, inhibiting spoilage bacteria growth, and suppressing protein degradation.

The preservation mechanism of thymol for meat products, including seafood, mainly entails suppressing the growth of spoilage fungi and preventing lipid oxidation, thereby prolonging shelf life. As shown in Table 3, the preservation effects of thymol on meat products are systematically summarized.

Table 3.

Thymol effect on meat preservation.

Application	Method	Quality	Reference
Pork	Chitosan nanoemulsions loading thymol or thyme essential oil	S. aureus↓, E. coli↓, color↑, pH↓, TVC↓	Liu and Liu (2020)
	Antifungal food packaging capable of sustained and unidirectional	Lipid oxidation↓, S. aureus↓, E. coli↓	Wang et al. (2023)
	As Food Active Packaging of Low-Density-Polyethylene-Based Films Incorporated with Rich in Thymol Halloysite Nanohybrid	haemoglobin iron↑, thiobarbituric acid reactive substances (TBARS)↓	Giannakas et al. (2023)
	Novel-Thymol@Natural-Zeolite/Low-Density-Polyethylene Active Packaging Film	haemoglobin iron↑, TBARS↓	Salmas et al. (2023)
Sea bass	Active polylactic acid/tilapia fish gelatin‑sodium alginate bilayer films	TVB-N↓, fungi count↓, TBARS↓, pH↓	Chen et al. (2022)
Chicken	Thymol-containing film	pH↓	Wang et al. (2022)
Beef	Controlled release and antifungal properties of PEO/casein nanofibers loaded with Thymol/β-cyclodextrin	fungi abundance↓	(Dai et al., 2022)
	Active essential oil (EO) components (thymol and carvacrol) were added at 0.4 % and 0.8 % (w/w)	Pseudomonas spp.↓, LAB↓, B. thermosphacta↓	Karam et al. (2020)
Trout fillets	Gelatin nanogel coating containing thymol and nisin	Listeria monocytogenes↓	Mohajer et al. (2021)

3.3. Other processed products

Thymol is currently widely utilized as a food additive due to its antifungal and flavor-enhancing properties. Wang, Tian, et al. (2022) demonstrated that adding low concentrations of thymol to skim milk at low temperatures effectively controlled Bacillus cereus contamination, thereby preventing food poisoning. Similarly, thymol demonstrates inhibitory effects against Penicillium aurantiogriseum at concentrations ranging from 0.03 to 0.09 mg/mL and exhibits bactericidal activity within the range of 0.05 to 0.15 mg/mL. In cheese products, thymol functions as both a preservative and an antimicrobial agent (Bukvicki et al., 2018). The application of a coating containing 1 % thymol essential oil on cheese bread has been shown to effectively suppress microbial growth on the bread's surface, retard staling, and consequently enhance the product's shelf life (Nourmohammadi, Hassanzadazar, Aminzare, & Hashemi, 2023). Amiri, Sepahvand, Radi, and Abedi (2024) found that thymol nanoemulsions could maintain the texture of sausages, enhancing their chewability, prevent further lipid oxidation, and inhibit microbial growth in sausages, confirming its dual efficacy in inhibiting lipid oxidation and maintaining texture stability. This finding aligns with the results reported by Sepahvand, Amiri, Radi, and Akhavan (2021); Sepahvand, Amiri, Radi, and Amiri (2022). As cheese maturity increased, both the content of monoterpenoid phenols and the antioxidant capacity assessed by FRAP and DPPH • assays exhibited a significant linear decrease (r ≥ 0.93, p ≤ 0.05). Compared to cheese lacking liposomal thymol, sheep cheese enriched with thymol nano-formulations exhibited markedly improved antioxidant properties and an extended shelf life of up to 180 days (Gil et al., 2022). Numerous studies have demonstrated that the incorporation of thymol into dairy products effectively inhibits fungal growth and prolongs shelf life (Degenek et al., 2023; Tatlisu, Yilmaz, & Arici, 2019). Unlike conventional addition methods, Chang, Mohammadi Nafchi, and Baghaie (2021) developed active films containing thymol for packaging mozzarella cheese. After coating, the films exhibited enhanced antifungal activity against Escherichia coli, Staphylococcus aureus, harmless Listeria, and Saccharomyces cerevisiae, while simultaneously reducing the growth rates of molds and yeasts. Additionally, Oliveira et al. (2025) found that pectin films containing thyme essential oil, when used to coat sausages, maintained higher antioxidant activity.

4. Conclusion and prospect

This article provides a comprehensive review of the antimicrobial properties of carvacrol and its role in food preservation. Extensive research has demonstrated that carvacrol significantly contributes to maintaining the quality of fruits, vegetables, meats, and processed food products during storage. Whether applied independently or in conjunction with other film-forming agents, carvacrol has been shown to retard moisture loss, inhibit color degradation, reduce nutrient depletion, and prolong the shelf life of fruits and vegetables by suppressing pathogenic microbial growth. Furthermore, carvacrol effectively diminishes moisture loss, lipid oxidation, and the proliferation of spoilage fungi in meat products. The preservative action of carvacrol is primarily attributed to its inhibitory effects on fungal and bacterial organisms, notably through inducing structural damage to fungal cell walls and membranes, culminating in cell death. Nonetheless, due to the inherent complexity of food matrices, the effectiveness of carvacrol may vary, complicating the precise elucidation of its underlying mechanisms of action.

The efficacy of thymol and packaging films in preserving the quality of fresh produce is influenced by a multitude of factors, including the specific of combined packaging materials utilized, the varieties of food, the types of pathogens present, and the methods of application. To fully understand the practical applications of thymol, further research is necessary to clarify its mechanisms and the interaction effects involved in the preservation of fresh produce. The use of advanced omics techniques, such as metabolomics, transcriptomics, and proteomics, may facilitate the elucidation of biological process alterations and the intricate interactions occurring in fruits during preservation. Despite the promising potential of thymol in these contexts, there is a notable deficiency in studies that explore certain dimensions of its applications, which should be prioritized for future research endeavors. There is a considerable amount of research on thymol, but studies on its application in meat product preservation are relatively superficial. Most research focuses on its antibacterial effects and the control of fruit quality, while studies involving the molecular mechanisms are comparatively limited. Future research could further explore its multifaceted mechanisms in greater depth.

CRediT authorship contribution statement

Donglan Luo: Writing – original draft, Investigation. Xue Li: Writing – review & editing, Methodology. Xiaogang Wang: Methodology, Data curation. Sen Cao: Investigation, Formal analysis. Liangjie Ba: Writing – review & editing, Project administration. Xiaohong Kou: Supervision, Conceptualization.

Funding

This research was funded by the National Natural Science Foundation of China (grant nos: 32302624), the Guizhou Key Laboratory of Agricultural Biosecurity [Qian Ke He ZSYS(2025)024], the Guizhou Province Science and Technology Basic Research Project {Qian Ke He Ji Chu(No. [2020]1Y140)}, and the sixth batch of “Thousand” level innovative talent projects in Guizhou Province (Zhu Ke He Tong GCC [2022]008).

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

Information will be provided upon request.