Patent Landscape Analysis of Bivalve Mollusc Decontamination Technologies: A Review

Abstract

Bivalve molluscs represent an important food source and have a significant economic impact through their commercialization in many countries. As high-capacity filter feeders, they can bioaccumulate contaminants and pathogens, creating tangible consumer health risks. This study presents the first comprehensive patent landscape of bivalve mollusc decontamination technologies indexed in international patent databases (Espacenet). The survey identified 30 patents filed between 1989 and 2025. Unlike reviews based solely on scientific literature, this work provides, for the first time, a global mapping of technological developments aimed at enhancing the safety of bivalves-derived foods. The analysis highlights depuration as the predominant technology, which continues to be refined and optimized. It also reveals the emergence of disruptive approaches—such as photodynamic sterilization, the use of probiotics, immunopotentiators, natural antimicrobial compounds, and genetic hybridization—developed to preserve the viability and sensory quality of the organisms. The novelty of this study lies in providing a technological overview of innovation within the aquaculture sector, emphasizing the transition from conventional methods to cleaner, integrated, and sustainable technologies. Furthermore, the research identifies the advancement of hybrid decontamination systems that combine microbiological efficiency, environmental preservation, and commercial value, contributing to safer and more technologically advanced shellfish production.

1. Introduction

Bivalves make a significant contribution to the global economy as a widely exported aquaculture food product. In 2022, global exports of bivalve molluscs reached USD 6.0 billion, accounting for approximately 3 percent of the total value of global aquatic animal product exports [1].

This food source has gained increasing popularity among consumers due to its recognized nutritional benefits, natural origin, and sustainability attributes. Moreover, bivalve aquaculture is deeply intertwined with cultural traditions and coastal tourism, substantially contributing to the socioeconomic development of many producing countries [1,2,3].

Represented by oysters, mussels, clams, and scallops, bivalves are filter-feeding animals that feed on plankton and other particles suspended in the water, being capable of processing large volumes of water daily [4]. As a consequence of this feeding mechanism, bivalves inevitably accumulate various environmental contaminants in their tissues, including marine biotoxins, heavy metals, pesticides, and microplastics [5,6,7,8,9]. Additionally, their filter-feeding activity facilitates the concentration of pathogenic microorganisms—many of which are of human origin—posing challenges to product quality, production efficiency, and trade [10,11].

Therefore, to prevent disease outbreaks and ensure food safety, post-harvest decontamination treatments are essential to reduce or eliminate contaminants and pathogens before commercialization. Currently, the main purification methods used for microbial decontamination include depuration, heat treatment, and high-pressure processing [12,13,14].

Despite these existing techniques, conventional methods are not always capable of removing all types of contaminants or pathogens, and they may also affect the sensory and nutritional quality of the final product [15]. Consequently, there is a growing need to develop innovative, effective, and sustainable technological approaches that enhance bivalve decontamination without compromising product integrity or market value.

Patent databases serve as a valuable scientific and technological resource for monitoring innovation trends over time. They centralize global information on patented technologies, enabling the mapping of emerging developments and the identification of innovation trajectories within specific fields [16]. Although several reviews have discussed methodologies for bivalve decontamination [17,18,19], no studies to date have provided a systematic patent-based analysis of this subject. Accordingly, this review presents a comprehensive investigation of patented technologies related to the decontamination of bivalve molluscs, providing an overview of global technological trends and innovations in this area.

2. Materials and Methods

The patent filing database used for the search was Espacenet (https://worldwide.espacenet.com/, accessed on 5 October 2025), a free search platform developed by the European Patent Organization (EPO) that contains patents filed by several countries worldwide.

The research was carried out in July 2023 and revised in October 2025, to identify existing technologies related to the decontamination of bivalve molluscs. The search terms included: “bivalve mollus*”—to capture variations such as bivalve mollusk and bivalve mollusc; “oyste*”—to include oyster and oysters; “shellfish”—to broadly capture all edible aquatic molluscs, including mussels; “cla*”—to retrieve documents related to Clams, Clam, and potentially the genus Clamys. These keywords were combined using the Boolean operator AND to narrow results to patents that addressed multiple relevant terms. The final query structure used was: “bivalve mollus” AND “oyste” AND “shellfish” AND “Cla*”. The use of the truncation character “*” ensured retrieval of plural and alternative word endings.

Based on the selected descriptor, a total of 916 patents were retrieved, all of which had their titles, abstracts, and descriptions reviewed, regardless of the year of filing. The inclusion criterion considered patents presenting technologies for the decontamination of bivalve molluscs of any species and for the removal of microorganisms described in the text. Several patents on unrelated topics—such as bivalve reproduction, chemical pollutant decontamination, and toxin detection—were also identified. Therefore, the exclusion criteria applied in this study are those presented in Figure 1.

The patents were organized in Microsoft Excel Office 2024 (LTSC) spreadsheets by title, patent identification code, publication date, country, and technology. The GraphPad Prism (GraphPad Software, Boston, MA, USA) version 8.0.2 software was used to create graphs for data illustration, and the figures were created using the BioRender illustration software 4.2 (Figure 2).

From this search, 30 patents on the decontamination of bivalve molluscs were found, and the following data were used for the discussion: year of publication, applicant country, application or granting of the patent, and which technology used for decontamination. Patents were classified according to the type of decontamination technology described in each patent. The patent search was limited by the coverage of the Espacenet database, which focuses on international and European registrations. National patents or patents in other languages may not have been retrieved. Recent documents under seal were also inaccessible. Thus, while the dataset offers a representative view of major technological advances, some relevant patents may have been out of scope due to language and database limitations.

3. Relevant Sections

Based on the described decontamination methodologies found, the patents were separated into the following categories: depuration, pressure and/or temperature treatment, probiotics, immuno-potentiators and vaccines, photodynamic sterilization, antimicrobial compounds or compositions, and bivalves hybridization methods (Figure 3). The countries, ranked in descending order based on the number of patents filed, were China (n = 8), the United States of America (USA) (n = 7), the World Intellectual Property Organization (WIPO) (n = 7), Spain (n = 3), Japan (n = 3), Portugal (n = 1), and the Republic of Korea (n = 1). Patents have been filed concerning methods for decontaminating bivalves, spanning 1989 to 2023 (Figure 4). Of all the documents analyzed, seven patents were granted: three related to depuration, two involving methodologies using pressure and temperature, one concerning an antimicrobial compound, and one focused on probiotics. Among the total, 15 patents have an active legal status, 14 were discontinued due to non-payment of fees or missing documentation, and one patent has expired.

3.1. Information About the Selected Patents

To our knowledge, this is the first effort dedicated to examining published patents on bivalve mollusk decontamination technologies. Given the varied legislations across different countries that require the decontamination of bivalves, applicable for both raw and fresh consumption, it becomes crucial to conduct a comprehensive survey of existing patented technologies.

China was the country with the highest number of patents filed, which was expected given that it is the most significant patent-filing country today, as well as the largest producer of bivalve molluscs in the world [1,20]. The United States ranks second in the number of patent filings, which may be related to its role as both a significant producer of bivalves and the world’s largest importer of aquaculture products [1]. It is important to note that the predominance of patent filings from China and the USA may not solely reflect higher levels of innovation, but also differences in patenting culture, governmental incentives, and institutional policies that encourage intellectual property protection. China, for instance, has implemented national programs to stimulate patent applications through academic and industrial sectors, resulting in a consistent rise in filings over the past decade.

Patents submitted directly to the WIPO were found (n = 7). The code of these patents starts with WO and is submitted to WIPO when the inventors intend to file the patent in more than one country. Submitting directly to WIPO allows inventors to obtain information on how the filing should occur in certain countries of interest since each country has different guidelines [21].

Of the 30 patents analyzed, 20 do not specify the bivalve species targeted. Among the remaining patents, six refer exclusively to oysters, two to oysters and clams, one to oysters and mussels, and one exclusively to clams. Among the patents that specify the bivalve species, oysters are the most frequently mentioned. One possible justification is their common consumption in raw form, which increases the need for effective decontamination methods to ensure food safety. Additionally, the high production volume of oysters may also contribute to the greater focus on this species in patent developments.

From 1989 to 2010, the filing of patents related to bivalve’s decontamination was low but constant, varying between methods. From 1989 to 2000, the main technologies addressed in the patents filed were antimicrobial compositions and depuration. However, starting in 2000, innovative patented technologies emerged, such as probiotics and pressure treatments. After that, there was a noticeable increase in patent filings from 2015 onwards, and among all technologies, depuration was the method present in almost the entire period covered. This finding is expected, given that depuration has been one of the principal methods for bivalve purification since the introduction of the earliest regulatory frameworks [22].

Due to the distribution of this technique throughout the entire patent filing timeline, it is evident that the search for optimizing depuration continues to be one of the main sources of research for decontaminating bivalves. While depuration is a well-established practice, its continuous exploration in patent filings indicates a potential for improving its execution.

3.2. Depuration

Depuration is one of the most commonly employed practices for decontaminating bivalve molluscs, particularly when applied to the trade of live bivalve molluscs, focusing on consuming them in natura. Other treatments often result in mortality of the animals and interfere with the sensory characteristics of bivalves, affecting consumer acceptance [23]. This post-harvest approach consists of placing the contaminated animals in tanks filled with clean seawater. The bivalves will naturally filter it, resulting in the elimination of microorganisms and contaminants previously bio-accumulated in the cultivation environment through their feces and pseudo-feces [24,25,26].

Tank depuration systems can be classified as static, continuous flow, and water recirculation modes. In static mode, the bivalves are placed in a tank containing clean or pre-treated water, which is changed at a specific time interval. In continuous flow mode, the water used is continuously added throughout the treatment time, while in recirculation mode, the initially added water is treated and reused for continuous purification [27,28]. The most conventional methods of decontaminating water used in purification systems include the use of ultraviolet light (UV), chlorinated compounds, and ozone [29,30,31].

Despite dynamically exploring the bivalve’s physiological filtration mechanism, depuration has limitations. The efficiency and optimization of depuration are multifactorial. They are influenced by several physical-chemical and biological aspects such as temperature, pH, salinity, oxygenation rate, bivalve’s stocking density, flow rate, size, and species of cultivated bivalves, among others [32,33].

Furthermore, depending on the pathogen, the necessary decontamination depuration time for safe consumption varies. Several countrie’s legal standards recommend microbiological quality control through monitoring Escherichia coli in bivalves as a fecal indicator bacteria. However, the clearance time for coliforms tends to be different from that required for other pathogens such as Vibrio spp. and enteric viruses, especially human norovirus genogroup I (NoV-GI) [34].

Among all the pathogens of concern associated with the raw consumption of molluscs, such as oysters, it is clear that NoV-GI requires a longer clearance time due to its ability to specifically bind to a receptor similar to the human histo-blood group A antigen, located in the digestive tract tissue of oysters, acting as a mechanism for concentrating viral particles and promoting resistance to elimination during depuration treatment [35,36]. Furthermore, other studies also show that there may be additional ligands that are capable of enhancing the bioaccumulation of NoV-GI in oysters [37].

Other important pathogens in food linked to bivalves are Vibrio spp., such as Vibrio parahaemolyticus and Vibrio vulnificus. Bacteria of this genus are considered ubiquitous in the environment and occur naturally in marine ecosystems and estuarine waters inhabited by bivalves [38]. Unlike coliforms that do not live in the marine environment, vibrios have a more complex adaptive arsenal that allows them to withstand changes in cleaning parameters, and they manage to remain longer in the body of bivalves [39,40,41].

To overcome the microbiological risks associated with pathogenic bacteria and viruses, technologies for an effective depuration process have been researched, developed and implemented. In the present review, 11 patents were found for the purification of bivalve molluscs, with the decontamination method having the largest number of patents filed. Most of the patents found contained in the description of the operating plan of the depuration system together with the target purification technology applied in the method.

In depuration systems, most oysters are placed in containers above the tank’s surface and arranged in a spaced manner to avoid recontamination by expelled feces that may contain aggregated microorganisms. Depuration plants generally consist of (i) purification tank, where the oysters are placed to carry out physiological filtration and consequently decontamination; (ii) water reservoir tank, which stores the water used for depuration and where water purification pre-treatment is also carried out (mainly with UV, chlorine, or ozone; (iii) macro and microfilters to retain debris, foam, and other larger particles that can carry aggregated microorganisms and harm water treatment; and (iv) circulation pump and oxygenator to pump water circulation and maintain correct water oxygenation. These characteristics may differ depending on the type of system used (static, continuous flow, or water recirculation) [27,28].

The methodologies found for optimization vary from physical to chemical principles. Patent CN115067259A (2022) [42] describes a depuration system that simulates natural tide changes. It reports that depuration is optimized by favoring the flow of debris and sediments through water circulation. Additionally, the cycle of water level changes caused by tide simulation stimulates the growth and purification of animals. Patent CN204168890U (2015) [43] describes a depuration system with water recirculation combining UV and ozone for water treatment, where a post-treatment fattening tank for bivalves was also designed, while patent CN101180980A (2008) [44] designs a non-circulating system aiming at low energy expenditure, economic cost, and operational ease.

Still within the principles of physical decontamination, patent US2016100558A1 (2016) [45] proposes to build a water reservoir below sea level at high tide. This reservoir is connected and supplied with seawater to promote water decontamination through natural processes such as sedimentation, exposure to solar UV light, and the predatory action of marine microorganisms against pathogens transmitted by sewage. The inventors state that depending on temperature and food availability, achieving a reduction of up to 4 Log₁₀ in oysters contaminated with NoV in six days was possible. Another interesting approach was a microbubble generator coupled to a depuration system described in patent WO2019138590A1 (2019) [46], in which bivalves can filter the bubbles that help desorb viruses (especially NoV) from the intestinal microvilli of the digestive tract, improving clearance efficiency.

Some patents involving compound addition combined with depuration were also found. Patent CN108668965A (2018) [47] addressed a treatment using a chlorinated disinfectant, obtaining a proportion of 40% to 60% of active chlorine in seawater for disinfection. Then, sodium thiosulfate is added to remove chlorine and ascorbic acid. Chitosan, carboxymethyl chitosan, or acid 2,3-dimercaptosuccinic are added as a heavy metal catalytic agent. Changing the cultivation water daily after this treatment results in a pathogen-free environment. Patent CN109819915B (2019) [48] proposes using a granulated fermented tea that acts as a purifying agent against pathogens, toxins, heavy metals, and other substances bioaccumulated in the organism of bivalves. The inventors of patent JP4393254B2 (2005) [49] describe a system that uses electrolytic water to enhance the decontamination of bivalves, which acts as a chemical oxidant for the decontamination of NoV. The methodology uses the physiological filtration activity of bivalves to pass electrolyzed water through the bivalve’s bodies and decontaminate them internally, suggesting it can be applied in a depuration system.

Another treatment described in patent US5482726A (1996) [50] combines pressurization with L-ascorbic acid, followed by pre-treatment with irradiation, and, finally, the molluscs are placed in depuration tanks in a continuous flow system coupled to ultrasonication devices. The inventors report this measure for post-harvest purification of bivalves for conservation on ships for transport to distant locations. All information about the description of the depuration systems found is briefly described in

Table 1. Patents describing depuration systems and optimization strategies for bivalve mollusc decontamination.

Title	Patent Number	Year	Technology	Target Bivalve Mollusc Species	Recommended or Tested Pathogens	Recommended Depuration Time
Tide-simulated bivalve mollusc purification system and purification method	CN115067259A	2022	Depuration system + simulating tides	Clams and oysters	Bacterial microorganism 1 and heavy metal	Not mentioned
Shellfish purification method and shellfish purification system	WO2019138590A1	2019	Depuration system + microbubble generator	No defined species 2	NoV	Not mentioned
Method for preparing shellfish purifying agent and method for purifying shellfishes	CN109819915B	2019	Depuration system + fermented tea	No defined species 2	Coliforms, heavy metal, and other substances	0.5–24 h
Breeding method for lowering bacterial quantity and heavy metal content in bodies of bivalve molluscs	CN108668965A	2018	Depuration system + chlorinated disinfectant and sodium thiosulfate	No defined species 2	Coliforms, other bacteria 1, and heavy metal	Not mentioned
Shellfish conditioning and depuration system with closed recirculation type	KR101799761B1	2017	Depuration system	Bivalve shellfish	Microorganisms such as NoV and Vibrio	Not mentioned
Shellfish depuration	US2016100558A1	2016	Depuration system in artificial reservoir	No defined species 2	Bacteria 1 and viruses (including NoV)	Approximately 6 days
Ocean bivalve mollusc purifying and manually fattening device	CN204168890U	2015	Depuration system	No defined species 2	E. coli	Approximately 24 h
Device for purifying microbiology in the body of seashell seafood and method thereof	CN101180980A	2008	Depuration system	Bivalve shellfish	Coliforms	4–40 h
Method for purifying bivalve, method for evaluating purification of bivalve, and device for purifying bivalve	JP4393254B2	2005	Electrolytic water	Oysters	NoV/Feline Calicivirus	Not mentioned
Method for reducing contamination of shellfish	US5482726A	1996	Depuration system + pressurization with ascorbic acid + irradiation	No defined species 2	Bacterial microorganisms 1	Not mentioned
Molluscs depuration system	ES2009416A6	1989	Depuration system	No defined species 2	Not mentioned	Not mentioned

¹ The bacterial species is not specified in the patent description. ² The patent suggests that the technology can be used for several species of bivalve molluscs.

.

Despite the technological advances and system optimizations described above, depuration still presents unresolved challenges that limit its universal efficacy. The process is highly dependent on environmental parameters such as temperature, salinity, oxygenation, and even the reproductive stage of the animals. Spawning events may occur during depuration due to stress or suboptimal environmental conditions, leading to the release of gametes and organic matter into the water, which increases turbidity and microbial load, consequently reducing depuration efficiency [51]. Moreover, while the method is effective against bacterial indicators such as E. coli, it remains less efficient for viral pathogens such as norovirus, which can specifically bind to oyster tissues and resist elimination [17]. Another limitation is the lack of standardization among depuration systems, making cross-comparison between studies difficult. Future research should focus on the integration of depuration with complementary technologies—such as plasma-activated water, photodynamic sterilization, or phage therapy—to enhance pathogen removal without compromising bivalve viability and sensory quality.

3.3. Pressure and Temperature

Pressure and temperature treatments for decontaminating bivalves are permitted by legislation for bivalves not purified by depuration processes. These approaches are recommended for final products that do not require fresh consumption of bivalves [12]. The European Union (EU) stipulates that for the bivalve mollusc treatment not subjected to depuration, an average heat treatment applying the parameters 90 °C for 90 s is necessary to promote safe consumption. However, the European Food Safety Authority (EFSA), through heat treatment models using the hepatitis A virus, states that other non-conventional treatments are effective in removing pathogenic microorganisms, making it necessary to create a performance criterion (PC) to validate these processes [12].

Despite the efficiency in microbiological control with high-temperature treatments, inactivation processes show a tendency to use treatments with higher pressure and lower temperature, such as treatment with high hydrostatic pressure (HHP), as this decreases changes in the sensory and nutritional characteristics and promotes better consumer acceptance of the food [52,53]. HHP consists of placing the packaged bivalves in a compression chamber filled with a compression transmitting fluid (generally water), and a pressurization force of up to 700 MPa is exerted for a programmed time without sudden variations in temperature occurring [54].

Four patents were found covering heat and temperature treatment methodologies (

Table 2. Patents describing pressure- and temperature-based treatments for the bivalve mollusc decontamination.

Title	Patent Number	Year	Technology	Target Bivalve Mollusc Species	Recommended or Tested Pathogens	Pressure, Temperature, and Time
Virus inactivation method in bivalve	JP2015171323A	2015	HHP + green tea extract	No defined species 2	NoV/feline calicivirus	300–500 MPa 3 min 20 °C
Procedure for the treatment of the seafood	ES2319037B1	2009	Pre-cooking + refrigeration + HHP	No defined species 2	Bacterial microorganism 1	Pre-cooking: 2–5 min at 85–120 °C HHP: 6000 bar for 5 min
Process of elimination of bacteria in shellfish and of shucking shellfish	US6426103B2	2002	HHP	No defined species 2	Vibrio vulnificus and other bivalve pathogens	10.000–100.000 psi 1–15 min up to 65.5 °C
Method for thermally treating bivalve and bivalve packed in container	JP2001029047A	2001	Heat treatment	No defined species 2	Not mentioned	120–125 °C for 2–4 min

HHP: High Hydrostatic Pressure. ¹ The bacterial species is not specified in the patent description. ² The patent suggests that the technology can be used for several species of bivalve molluscs.

). Patent US6426103B2 (2002) [55] describes an HHP treatment using a pressure range of 10.000 to 100.000 psi over 1 to 15 min between 25.5 °C (room temperature) and 65.5 °C. In the experiments, oysters contaminated with V. vulnificus were purified by treatment with a pressure of 50.000 psi for 5 min at room temperature (microbial reduction: 20.000 to 0 MPN/g). The inventors report the possibility of increasing or decreasing the pressure. However, the temperature and time must also be increased or decreased, allowing for parameter variations using the proposed methodology.

The inventors of patent JP2015171323A (2015) [56] also carried out an HHP treatment on oysters to combat NoV contamination. For this, oysters were pre-treated with a green tea extract in a range of concentrations (0.01–1%) that contains compounds derived from catechin, which has described antiviral activity. Following pre-treatment, oysters were subjected to HHP between a range of 100–500 MPa, where they found that a 3-min treatment at 300 MPa with a concentration of 0.1% of the extract was sufficient to reduce the titer of Feline Calicivirus significantly. Moreover, other tested parameters of the methodology also indicated successful inactivation results.

Patent ES2319037B1 (2009) [57] includes HHP in one of the steps of the treatment methodology to preserve the shelf life of refrigerated bivalves-based products. The bivalves are pre-cooked, followed by refrigeration, packaging, and treatment with HHP, using a pressure of 6000 bar for 5 min to reduce the bacterial load. Using only temperature, a heat treatment model was developed in patent JP2001029047A (2001) [58], which promotes packaging and cooking by electrical heating of bivalves. The inventors suggest that treatment at a temperature of 120–125 °C for 2 to 4 min is necessary for long-term storage.

Recent developments have focused on combining high hydrostatic HHP with natural bioactive compounds or mild thermal treatments to enhance microbial inactivation while maintaining product quality. Studies and patents have explored the synergistic effects of HHP with natural antioxidants such as catechins, ascorbic acid, and chitosan derivatives, which may improve viral and bacterial inactivation by destabilizing microbial membranes or inhibiting oxidative stress. These combinations could also help preserve sensory and nutritional characteristics compared to conventional heat treatments.

3.4. Immuno-Potentiators and Vaccines

Immuno-potentiators and vaccines are treatment options in aquaculture to increase animal immunity against pathogenic microorganisms. As an alternative to antibiotics, which contribute to the spread of antimicrobial resistance in the environment, immuno-potentiators such as peptides and other natural compounds are welcome to help manage animal health by promoting the activation of the immune system and acting as growth promoters [59,60]. Furthermore, immuno-preparations containing antigens show promise in controlling certain specific viral and bacterial diseases that can impact the development and quality of bivalves [61].

Three patents on immuno-potentiators and vaccines were found (

Table 3. Patents involving immuno-potentiators and vaccines for enhancing the resistance of bivalve molluscs against pathogens.

Title	Patent Number	Year	Technology	Target Bivalve Mollusc Species	Recommended or Tested Pathogens	Described Composition of the Formulation
Composition for the treatment and/or prevention of marine mollusk viral infection	WO2021229086A1	2021	Antiviral composition	Oysters	Viruses from the Herpesviridae family	Inactivated viral particle and absorption promoters
Purifying method for bivalve molluscs	CN105248342A	2016	Immuno-potentiator	Oysters or mussels	V. parahaemolyticus, E. coli, Norwalk virus and astrovirus	Selenomethionine, EDTA-FeNa, EDTA-ZnNa, and β-glucan
Methods of rapidly producing improved vaccines for animals	WO2013066665A1	2013	Vaccine formulation	No defined species 2	Not mentioned 1	Nucleic acid

¹ The bacterial species is not specified in the patent description. ² The patent suggests that the technology can be used for several species of bivalve molluscs.

). Patent CN105248342A (2016) [62] describes an immuno-potentiator to be added to bivalve cultivation water composed of selenomethionine, EDTa-FeNa, EDTA-ZnNa, and β-glucan. Selenomethionine and β-glucan act with immuno-potentiating power, while Fe and Zn antagonize heavy metals that may be bioaccumulated in bivalves.

The inventors of patent WO2021229086A1 (2021) [63] carried out the inactivation of ostreid herpesvirus type 1 (OsHV-1) particles, a pathogen in oysters. They administered the injection treatment to analyze whether the development of immunity against this pathogen was found. According to the results, oysters inoculated with inactivated viral particles showed a higher survival rate when compared to the untreated control group. Another patent was also found (WO2013066665A1; 2013) [64] describing a rapid method for developing a vaccine for animals, where a fragment of nucleic acid isolated from a contaminated animal is used and not the entire attenuated pathogen. Although the patent was developed for fish, its description mentions that bivalves, such as oysters and clams, may also benefit from the technology.

Immunostimulants (immunopotentiators) and vaccines have emerged as complementary and sustainable approaches for disease control in bivalves, especially oysters, in the context of modern aquaculture. Immunostimulants—including β-glucans, peptidoglycans, lipopolysaccharides, alginates, levamisole, and cytokines—act by strengthening the molluscs’ innate immune system, increasing their resistance to bacterial and viral pathogens without disrupting the natural microbiota. Vaccines, which can be live-attenuated, inactivated, subunit, or DNA-based, aim to induce specific immune responses against agents such as Vibrio spp. and Ostreid herpesvirus-1 (OsHV-1). Although they present practical challenges—such as the difficulty of application in large populations and the slow induction of immunity with inactivated vaccines—these strategies represent promising alternatives to antibiotic therapy, promoting greater biosafety and sustainability in bivalve aquaculture production [65].

3.5. Probiotics

According to the International Scientific Association for Probiotics and Prebiotics (ISAPP), probiotics can be defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”. They promote general benefits for maintaining a healthy digestive and immune system, in addition to the possibility of acting against the colonization of pathogenic microorganisms [66].

In aquaculture, they are administered together with food or dispersed in the water to act on the aquatic microbiota, improve water quality, and reach the animal organisms [67]. In bivalve molluscs, probiotics can be applied in hatcheries that provide seeds and larvae for cultivation, as they are a target for disease outbreaks, reducing the mortality rate [68]. Probiotics are also a viable tool for combating the indiscriminate use of antibiotics in aquaculture being an eco-friendly alternative to the methods already available for disease controlling [69].

Of the three patents on the application of probiotics found (

Table 4. Patents on the application of probiotic microorganisms for the prevention and control of diseases in bivalve molluscs.

Title	Patent Number	Year	Technology	Target Bivalve Mollusc Species	Recommended or Tested Pathogens	Probiotic Microorganisms
Biological control of vibriosis in aquaculture	WO2023046966A1	2023	Probiotics	Clams (Venerupis philippinarum)	Pathogenic Vibrio tapetis	Non-pathogenic Vibrio tapetis
Marine bacteria formulation useful in aquaculture	US11851644B2	2020	Probiotics	Oysters (Crassostrea virginica)	Vibrio coralliilyticus	Phaeobacter inhibens, Pseudoalteromonas piscicida
Probiotic system for aquaculture	WO2006132944A2	2006	Probiotics	Oysters (Crassostrea gigas)	Vibrio tubiashii	Pseudoalteromonas spp.

), two of them (WO2006132944A2, 2006 [70] and US11851644B2, 2020 [71]) use probiotic strains of the genus Pseudoalteromonas to combat vibriosis in oysters in the larval stage. Both resulted in a lower mortality rate compared to the control. Patent WO2023046966A1 (2023) [72] used a non-pathogenic strain of Vibrio tapetis to reduce the incidence of brown ring disease in clams, which is caused by virulent strains of these bacteria, obtaining results in reducing the cytotoxic effect of the pathogen in samples treated with the probiotic.

Probiotics have emerged as one of the most promising strategies for managing bivalve health, offering a sustainable alternative to the use of antibiotics in aquaculture. Species of Bacillus, Lactobacillus, Phaeobacter, Alteromonas, and Roseobacter can benefit oysters through several mechanisms, including pathogen inhibition, such as Vibrio spp., competition for nutrients and adhesion sites, production of antimicrobial substances, and positive modulation of the associated microbiota. Furthermore, their application can improve growth, larval survival, and resistance to environmental stress, contributing to water quality and the safety of the final product. However, the practical adoption of these microorganisms requires careful selection of specific strains for each oyster species and life stage, ecological compatibility testing, standardization of doses and application methods, as well as the development of regulations that ensure efficacy, biosafety, and economic viability on an industrial scale [65].

3.6. Antimicrobial Compounds

Antibiotics are used in aquaculture for disease control and growth promoters. However, its irrational use has led to public health and food safety concerns, including the development of antimicrobial resistance and the generation of antibiotic residues, which, if ingested, pose a risk to the health of consumers [73]. In bivalve molluscs, the practice of using antibiotics for cultivation is not common [74], but since they are filter-feeding animals, they can bioaccumulate residues of antimicrobials dispersed in the water if the cultivation environment is not suitable [75,76,77]. To promote the fight against antimicrobial resistance, research into natural compounds is encouraged, such as phytocompounds, and secondary metabolites from fungi and algae, among others [78,79,80].

Five patents covered antimicrobial compounds or solutions applied as decontaminants (

Table 5. Patents describing antimicrobial compounds and formulations for decontaminating bivalve molluscs and aquaculture environments.

Title	Patent Number	Year	Technology	Target Bivalve Mollusc Species	Recommended or Tested Pathogens	Antimicrobial Compound
New endoperoxide compounds, process for obtaining them and uses thereof for control of perkinsiosis in bivalves	WO2020240266A1	2020	Antiparasitic compounds	No defined species 2	Perkinsus olseni	Endoperoxide compounds
PACAP for the treatment of viral infections in aquatic organisms	PT2647369T	2017	Antiviral compound	No defined species 2	Viral hemorrhagic septicemia virus (VHSV)	Pituitary Adenylate Cyclase Activating Polypeptide (PACAP)
Compositions and methods for reducing or preventing microorganism growth or survival in aqueous environments	WO2008008362A2	2008	Antimicrobial water treatment	Not mentioned	Bacterial pathogens 1	Aliphatic heteroaryl salt, trichloromelamine and other compounds
Novel antibiotics against Vibrio anguillarum and the applications thereof in cultures of fish, crustaceans, molluscs and other aquaculture activities	ES2204294B2	2004	Antibiotics	Oyster (Ostrea edulis) and Clam (Ruditapes decussatus)	Vibrio anguillarum	Diketopiperazines
Process for treating fish and shellfish to control bacterial contamination and/or growth	US5262186A	1993	Decontaminating solution	No defined species 2	Pseudomonas aeruginosa, Bacillus cereus, Moraxella osloensis	Trialkali metal phosphate

¹ The bacterial species is not specified in the patent description. ² The patent suggests that the technology can be used for several species of bivalve molluscs.

). US5262186A (1993) [81] describes a solution containing tri-alkali metal phosphate that promotes superficial bacterial disinfection of eviscerated bivalves without affecting the organoleptic characteristics. The results showed a reduction of >99% when treated in fresh water for 60 s, but in salt water, the decontamination effectiveness was only 30%.

Patent ES2204294B2 (2004) [82] refers to the registration of new antibiotics developed for general application in aquaculture against Vibrio anguillarum, a pathogen that affects several cultivated species. The compounds are diketopiperazines isolated from marine bacteria and increase larvae’s survival rate in a range of 12–33% when added to cultivation.

Patent PT2647369T (2017) [83] describes a pituitary adenylate cyclase-activating polypeptide (PACAP) as a possible antiviral agent that can be applied to cultivated bivalves. The treatment consists of immersion baths for 2 to 3 days, where the analysis revealed that when the peptide is administered together with another antiviral (ribavirin), the survival rate is increased. Although the patent primarily focuses on fish, it explicitly states that the invention demonstrates, for the first time, both in vitro and in vivo, a relationship between PACAP and the antiviral response not only in fish, but also in crustaceans and bivalves, indicating potential applicability of the technology to these groups.

WO2008008362A2 (2008) [84] offers a treatment for water contaminated by microorganisms in general, which may include water used in aquaculture systems. The proposed treatment consists of adding an antimicrobial composition containing in its formulation an aliphatic benzyl alkyl ammonium salt, trichloromelamine, and at least two ammonium salts. In some trials, there was a 100% reduction in bacterial growth with a 1% concentration of the antimicrobial composition against E. coli, Salmonella Typhimurium, and Listeria monocytogenes. Having the parasite Perkinsus olseni as the etiological agent, WO2020240266A1 (2020) [85] describes endoperoxide compounds for the treatment and prophylaxis in bivalves.

Traditional antibiotic-based treatments can result in residual accumulation within bivalve tissues and contribute to environmental dissemination of resistance genes. In contrast, many of the patented antimicrobial formulations identified in this review explicitly aim to mitigate these risks by employing natural or biologically derived compounds, such as peptides (e.g., PACAP), endoperoxides, and phytochemical extracts with antimicrobial properties. These agents typically act through membrane disruption or oxidative mechanisms rather than specific metabolic targets, which reduces the likelihood of inducing bacterial resistance. Additionally, the patents describe applications that minimize drug residues in edible tissues. Such innovations align with the growing trend toward the use of eco-friendly antimicrobial strategies in aquaculture, contributing to safer and more sustainable bivalve production systems.

3.7. Photodynamic Sterilization

Photodynamic sterilization involves inactivating viruses and bacteria through a photosensitizing agent. When in contact with a light source at a specific wavelength, the agent becomes reactive oxygen species interacting with microorganisms, causing irreversible damage to their structure and leading to inactivation [86].

It has been considered a promising technique for application in the food industry because it is a clean sterilization method (without producing toxic residues), easy to perform, and does not induce the development of resistance in microorganisms [87]. As it does not use the thermal principle, photodynamic sterilization has been studied in application as a methodology for decontaminating bivalves as it preserves the organoleptic characteristics of the final product, in addition to many studies demonstrating its effectiveness in inactivating different microorganisms [88,89,90,91].

In this research, three patents addressing this methodology were found (

Table 6. Patents describing photodynamic sterilization methods for bivalve mollusc decontamination.

Title	Patent Number	Year	Technology	Target Bivalve Mollusc Species	Recommended or Tested Pathogens	Photosensitizer
Photodynamic method to decontaminate surfaces	US2022023454A1	2022	Photodynamic sterilization	Depuration water	Feline Calicivirus, Tulane virus	Rose bengal and phloxine-B
Novel water product photodynamic cold sterilization fresh keeping method	CN106857784A	2017	Photodynamic sterilization	Oysters	Not mentioned	Curcumin
Photodynamic cold sterilizing and fresh-keeping method	CN104304408A	2015	Photodynamic sterilization	Oysters	Not mentioned	Curcumin

), two of which were filed by the same group of inventors. Patents CN106857784A (2017) [92] and CN104304408A (2015) [93] describe a treatment in oysters and aquatic products using the photosensitizer curcumin, demonstrating a bacterial reduction of at least 94% compared to the control.

Patent US2022023454A1 (2022) [94] uses rose bengal and phloxine-B as photosensitizers to decontaminate food surfaces and aqueous solutions. The inventors claim that the methodology can be applied to decontaminating water used to purify bivalve molluscs. A reduction > 4.0 Log₁₀ of laboratory substitutes for NoV (Feline Calicivirus and Tulane virus) was obtained in a treatment using LED light blue in 3–10 min.

Despite the growing evidence supporting the effectiveness of photodynamic inactivation (PDI) as a non-thermal and eco-friendly approach for controlling pathogens in bivalves, several constraints limit its large-scale application in the aquaculture and food industries. One major issue is scalability—translating laboratory success to industrial settings is challenging due to variability in light penetration, photosensitizer (PS) distribution, and the shielding effects of complex food matrices, such as oyster tissues, which can reduce treatment efficacy [87,88].

Additionally, cost-effectiveness remains a concern, as maintaining controlled illumination systems and using high-purity or encapsulated photosensitizers (e.g., curcumin, rose bengal) can increase production costs compared to conventional sanitization methods [90]. From a regulatory standpoint, the lack of standardized safety guidelines and approval processes for food-grade PSs or their residues in edible products hinders widespread adoption. Moreover, potential effects on sensory properties and consumer acceptance must be carefully evaluated to ensure commercial viability. Therefore, while PDI shows strong potential for pathogen control and shelf-life extension in oysters and other bivalves, overcoming these technical, economic, and regulatory challenges is essential for its practical industrial implementation.

3.8. Hybridization

Hybridization (intra/inter-species hybridization) involves crossing different species of animals to obtain a genetically improved hybrid. In molluscs, it is practiced to obtain specimens with a greater degree of adaptation to environmental factors (e.g., pH, salinity, temperature), increase the quality of the meat, and optimize the physiological responses of the immune system against diseases [95,96].

A single patent (US2010263600A1; 2010 [97]) addressing this methodology was found. In its description, the technique consists of hybridizing an oyster of the pathogen-resistant species Ostrea edulis with another non-resistant species. The resistant oyster was described as a wild oyster that has not suffered anthropogenic actions, while the non-resistant oyster was any oyster sensitive to pathogens regardless of origin, genus, or species.

Recent research on hybridization in the Pacific oyster (Crassostrea gigas) has highlighted its strong potential for genetic improvement, particularly in enhancing growth, survival, and stress resistance under varying environmental conditions. Studies combining the fast-growing “Haida No. 1” line with the inbred orange-shell line demonstrated significant heterosis, with hybrids showing superior performance in survival rates, growth traits, and physiological resilience across different culturing environments. Hybrid lines also exhibited enhanced metabolic adaptability and immune stability when exposed to temperature and salinity fluctuations, suggesting that hybridization can effectively mitigate mass mortality events linked to environmental stressors [95,96]. However, despite these promising results, several challenges remain before hybridization can be widely applied in commercial aquaculture. Therefore, while hybridization represents a promising avenue for sustainable oyster aquaculture, its widespread application will require integrated genetic, environmental, and economic strategies to ensure reliability and long-term viability.

3.9. Future Directions

Although various technologies were discovered, some of the patents analyzed for certain disinfection methods did not contain scientific data highlighting important parameters such as the cleaning time required to completely remove microorganisms, whether the described technology is effective in removing all major contaminants and bivalve pathogens, and which main bivalves can be treated. This is because many patents are filed as utility models, presenting only a description of the system and its operation.

Other technologies for decontaminating bivalves not discussed here are described in the literature, such as dielectric barrier discharge plasma (DBDP), plasma-activated simulated seawater (PASW), and the use of bacteriophages in the bivalves’ purification [98,99,100,101]. This may be because the descriptor code used has not covered patents for other methods, or the inventors have not yet filed patents on the given method.

Plasma-based sterilization has recently received growing attention as an eco-friendly and residue-free disinfection strategy. Studies using PASW demonstrated that non-thermal plasma treatment effectively reduces Escherichia coli and total coliform counts in live oysters during depuration, without affecting their texture or viability [98]. Similarly, DBDP has shown strong antiviral activity against hepatitis A virus in oysters while preserving product quality, highlighting its potential as a non-thermal method compatible with raw seafood processing [100]. Another promising approach is the use of bacteriophages—viruses that selectively infect and lyse bacteria—as biological control agents during the depuration process. A study [99] demonstrated that combining bacteriophage therapy with traditional depuration significantly accelerated E. coli removal from cockles (Cerastoderma edule). Collectively, these innovative but not yet patented technologies—plasma-based treatments and bacteriophage-assisted depuration—represent important research frontiers for improving food safety in bivalve aquaculture. Their future implementation will depend on further optimization of scalability, cost-efficiency, and regulatory approval processes, but they clearly point toward a transition to cleaner, more sustainable, and non-residual decontamination methods.

Furthermore, many depuration-related patents lack quantitative validation or standardized performance criteria, making it difficult to assess their real-world efficiency. Few documents report operational parameters related to animal physiology, such as reproductive status, which can strongly influence depuration outcomes. Spawning events triggered by environmental stress or temperature fluctuations may lead to high organic loads in the tanks, decreasing water quality, and hindering microbial clearance. Addressing these biological and operational variables in future patent designs and experimental validations will be essential for improving reproducibility and scalability.

It is worth mentioning that the patent deposit can be submitted on behalf of universities where the researchers carried out the method, and there may be institutions that are not encouraged by the country to carry out the deposit, as it is an expensive financial process [101].

4. Conclusions

From the data collected through the patent search on bivalve decontamination methodologies, an increasing number of emerging trends and technological innovations can be observed, highlighting the continued relevance of this research domain for ensuring the safe consumption of bivalves.

Depuration was the predominant methodology within the time range covered in this study, underscoring its enduring importance in the current scientific and technological landscape. The technological landscape demonstrates that, rather than being replaced, depuration systems have been continuously refined through innovations such as microbubble generators, tidal simulation systems, and the incorporation of natural compounds like green tea extracts, which serve as effective optimizers compared to conventional models.

However, despite these developments, depuration remains limited in its ability to remove viral pathogens (particularly norovirus) effectively, and it is sensitive and influenced by environmental variables such as temperature, salinity, and spawning events. Moreover, the lack of standardized operational protocols across patents restricts reproducibility and comparability among systems.

Beyond depuration, this review identifies emerging complementary technologies—including photodynamic sterilization, probiotics, immuno-potentiators, and antimicrobial peptides—that collectively signal a paradigm shift toward integrated, non-thermal, and sustainable decontamination systems. Yet, many of these patents remain at the conceptual or laboratory scale, lacking quantitative validation, cost–benefit assessment, and regulatory acceptance for commercial use. Further studies should address viral persistence mechanisms in bivalve tissues, interactions between probiotics and native microbiota, and the long-term ecological effects of new decontamination compounds.

In summary, the patent landscape reveals a transition from conventional to multifunctional, clean, and sustainable decontamination strategies, aligning with global efforts to enhance food safety in aquaculture. Addressing the identified scientific, technical, and regulatory gaps will be crucial to accelerate the industrial implementation of these innovations and ensure the safe and sustainable commercialization of bivalve molluscs worldwide.