Development of a Blockchain-Based Food Safety System for Shared Kitchens

Abstract

With the recent growth of the sharing economy, businesses offering shared-kitchen services are expanding rapidly. Due to the communal nature of these kitchens, there is a heightened need for systematic food safety management. However, existing research on blockchain applications has largely overlooked shared kitchens, a complex setting with numerous stakeholders and sensitivity to real-time kitchen conditions. This study addresses this gap by proposing a blockchain-based food safety management system for shared kitchens. The system’s functional requirements were meticulously outlined based on guidelines from South Korea’s Ministry of Food and Drug Safety. Key participants were identified as system users, and use cases were crafted in alignment with their responsibilities and roles to ensure effective safety management. Additionally, the blockchain system’s mechanisms for enhancing safety in shared kitchens were substantiated through specific use cases and detailed data structures, addressing issues related to forgery, alteration, and management challenges. This study also offers practical insights that can facilitate more structured safety management in shared-kitchen environments.

1. Introduction

The sharing economy platform—a contemporary business model enhancing efficiency and sustainability—is rapidly expanding [1]. Defined as an economic model where services, including short-term rentals of both tangible and intangible assets, are made available to others, the sharing economy facilitates resource optimization [2]. Shared-use kitchens, also known as kitchen incubators, exemplify this model within the food industry. Originating in the United States in the 1980s, these facilities allow individuals in the restaurant industry to rent kitchen space on an as-needed basis, promoting flexibility and reduced overhead costs. Local food and beverage (F&B) startups seeking to lower fixed expenses, such as rent and labor, can utilize kitchen spaces provided by shared-kitchen operators at designated times and locations [3]. Shared kitchens provide self-employed restaurateurs with a cost-effective means to operate by minimizing rental expenses [4]. In South Korea, the shared-kitchen market is valued at approximately KRW 1 trillion (equivalent to USD 740 million) and is projected to expand. Notably, 10% of entrepreneurs who test their concepts in shared kitchens advance to full commercialization, with a remarkable 90% survival rate in the competitive market. Thus, shared kitchens are becoming indispensable for small-scale restaurant startups in Korea.

With the emergence of new shared-kitchen businesses and the expansion of this sector, food safety management has gained increasing importance [3,5]. By design, and in addition to overall food safety management, shared kitchens are exposed to the risk of cross-contamination of kitchen facilities and food owing to the multiple users. For instance, the U.S. Food and Drug Administration (FDA) has defined scenarios where hazard analysis and critical control points (HACCP) standards must be applied in shared kitchens. The FDA’s “HACCP implementation in a shared kitchen environment” report delineates the roles and responsibilities of shared-kitchen users and operators, guiding HACCP application within these spaces “https://www.studocu.com/ph/document/access-computer-college/hospitality-management/haccpimplementationinasharedkitchenenvironment2019/70820544 (accessed on 1 May 2019)”. Similarly, the Korean Ministry of Food and Drug Safety has instituted legal frameworks for shared-kitchen operations, encompassing safety management and insurance requirements. A specialized system has also been introduced, allowing shared-kitchen facilities to receive HACCP certification tailored to their unique operational needs.

The issue of counterfeit food, such as the forgery and alteration of food packaging, is increasingly prevalent in the food market. Between 2010 and 2021, over 3000 fraud cases involving Korean beef labeling and grading occurred in Korea. Blockchain-based traceability technology is emerging as a solution for improving shared-kitchen operations and preventing the falsification of food information [6]. Using blockchain technology to record and manage data related to shared kitchens securely is critical for fraud prevention [7]. For example, Walmart, a major U.S. retail company, has implemented blockchain solutions to manage its food supply chain [8,9]. The food distribution industry is actively adopting blockchain-based traceability systems [10].

In modern food safety, critical challenges include ensuring a clear product history, preventing contamination during distribution, and mitigating the risk of information manipulation [11]. Although existing blockchain systems in the food technology industry address supply chain traceability, they rarely consider the specific characteristics of the shared-kitchen business model. Shared kitchens are more vulnerable to food safety issues due to their multi-user environment and close connection to food handling. Therefore, shared-kitchen management systems must address factors beyond traditional tracking, such as shared resources (e.g., ingredient storage and cooking facilities), space types, operational entities, and participating stakeholders. However, limited research has explored food safety management in shared kitchens and considered each type’s unique characteristics [12].

A shared-kitchen ecosystem involves multiple stakeholders, from leaseholders and lessees to shared-kitchen branches and regulatory bodies. Roles and responsibilities vary among stakeholders, necessitating a blockchain-based management system that defines roles, management scope, and access rights to information. This study designs safety management criteria and system participant roles, reflecting the unique characteristics of shared kitchens to create a comprehensive safety management platform. The proposed blockchain system also extends from private to consortium networks to accommodate diverse user groups. We discuss the design of a consortium network and the configuration of user groups with tailored data access levels and functional roles, focusing on South Korean shared kitchens. The proposed system assesses functional requirements based on South Korea’s Ministry of Food and Drug Safety guidelines. To summarize, we outline the following research questions: (1) Who are the stakeholders in shared-kitchen food safety, and how should their roles and responsibilities be defined? (2) Based on these definitions, how can a blockchain system be designed for shared-kitchen management, and what functional requirements are essential? (3) What are the critical use cases, required data structures, and flow mechanisms?

2. Background

2.1. Blockchain

Blockchain is a distributed data storage technology that transparently records transaction details on a digital ledger that anyone can read and duplicate and store across multiple computers [13,14]. Because the records are distributed and stored in “blocks” across various blockchain locations, it is extremely difficult to manipulate or distort this information. A block is a unit of data that contains transaction details, and these blocks are linked to form a secure, continuous sequence or a chain. Consequently, hacking blockchain records is virtually impossible, ensuring that information remains intact [15]. Blockchain combines distributed processing with encryption technology, offering high security and enabling transaction speed, transparency, and cost reduction. Additionally, due to its robust security and reduced susceptibility to forgery and alterations, blockchain is applicable in various areas requiring proof of data integrity [16,17].

The core concept of blockchain is decentralization, which supports peer-to-peer (P2P) transactions. In blockchain networks, transaction data are recorded and managed by all participants rather than a central server. These participants operate through nodes, which are individual computers or devices within the blockchain network responsible for validating and storing data. Each transaction generates a “block” containing transaction details, which links to previous blocks and is distributed across all participating computers. This decentralized structure also enables smart contracts, which are self-executing contracts with the terms of the agreement directly written into code, allowing automated transaction processing without intermediaries. Due to this design, altering or hacking the blockchain would require simultaneous modification by more than half of all participants, making such actions nearly impossible.

Blockchain is typically classified into three types based on its applications: private, public, and consortium (

Table 1. Blockchain-type features.

Features	Public Blockchain	Consortium Blockchain	Private Blockchain
Operator	All trading participants	A member of the consortium	One central authority has full authority
Governance	Difficult to change the rules once established	Laws can be changed by the agreement of consortium participants	The rule can be changed easily depending on the decision-making of the central agency
Transaction speed	Difficult to scale the network and slow down transactions	Easy network expansion and fast transaction	Easy network expansion and fast transaction
Data access	Accessible to anyone	Accessible only to authorized users	Accessible only to authorized users
Anonymity	Anonymity	Identifiable	Identifiable
Proof of transaction	Transaction proof is determined by algorithms, such as PoW and PoS. Transaction proof is not known in advance	Transaction verification and block generation are made according to known status/pre-agreed rules through certification of the transaction attestor	Proof of transaction by central authority
Use cases	Bitcoin, Ethereum	R3CEV, CASPER	Link, hyperledger fabric, Nasdaq unlisted stock exchange platforms

). Private blockchains depend entirely on a single service provider, posing reliability limitations that can be mitigated through temporal transactions and having limits to its reliability [18]. Consortium blockchain, an extension of the private model, links disparate private blockchains by connecting heterogeneous blocks through “ordering” [19].

Table 2. Blockchain characteristics.

Characteristics	Advantage
A shared ledger	By sharing information within the network, you can flexibly cope with the risk of a “single point of failure” that can be problematic in a centralized system
An agreement process	Improve reliability and transparency of information through consensus among network members
Tracking information	In the blockchain system, transaction details are recorded and stored in blocks in chronological order, thus enabling tracking of the entire transaction history
Information invariance	Distributed ledger technology makes it impossible to change information arbitrarily because network members share the same information
Payment completeness	Transactions completed through blockchain cannot be canceled
Smart contracts	Coding a blockchain system based on the conditional statement “if this, then that” enables the automatic execution of contracts without transaction intermediaries

provides a summary of blockchain characteristics.

Consortium blockchain is an intermediate form between public and private blockchains. Unlike private blockchains, where a single owner has complete authority, consortium blockchains grant authority to preselected nodes [20]. The primary difference between public and consortium blockchains is participant permissions [21]. Because consortium blockchains allow selective access, they address the public blockchain’s limitation of requiring all data to be visible to every participant [22]. Operating on a trusted network restricted to authorized entities, consortium blockchains use efficient consensus algorithms to optimize transaction processing speed and maintain data integrity, making them ideal for industries that require secure information sharing within complex organizational environments [23]. Consortium blockchains can enhance security by limiting participation while maintaining a decentralized structure, solving the challenges of low transaction speed and limited network scalability often seen in public blockchains [23]. Additionally, consortium blockchains are governed by two types of entities: governors and members. Governors perform six core functions within the governance framework, enabling key decisions through decentralized governance [22]. In this study, we design and implement a blockchain system by defining essential transaction elements, including actions, items, and orders, to create a smart contract for managing on-chain data.

Blockchain consists of an ordered list of nodes and links; nodes store information and are connected through chains [24,25]. Blockchain’s application has recently expanded across various fields due to its technological strengths. For instance, a consortium network is used in the medical field to securely share treatment information for infectious disease patients [26]. Medical data distribution across multiple systems allows blockchain management to prevent unauthorized data sharing and protect patient privacy. Additionally, as e-government systems manage sensitive information, a decentralized and secure e-government system based on consortium blockchain technology has been proposed [27]. Another application involves a consortium blockchain-based electronic portfolio management system integrated with a recruitment platform to securely manage and transmit e-portfolios [28].

As the scope of blockchain applications continues to grow, research in various fields has increased substantially [29]. First, in finance, blockchain enhances transaction transparency and stability while improving the security and performance of distributed ledgers through privacy protection technologies [30]. Smart contracts enable automated contract execution and real-time tracking of financial transactions. Second, blockchain tracks product origins in distribution and prevents forgery and tampering [31]. Research in this area focuses on improving supply chain efficiency and transparency by developing smart contracts and origin-tracking algorithms. Third, blockchain technology is applied in logistics to improve real-time tracking and data management, enhancing transparency and addressing security concerns [32]. A blockchain-based system enhances transparency by facilitating real-time tracking and addressing security issues. In the food industry, blockchain is also used to ensure the traceability and safety of agricultural products [33]. Research continues to focus on quality control and safety enhancement by integrating blockchain with Internet-of-Things (IoT) technologies.

Blockchain is highly secure, is resistant to forgery, and can be managed within a decentralized network. Consequently, it is applicable across a broad variety of fields [24]. The convergence of blockchain with emerging technologies, such as cloud computing and the IoT, is becoming essential in today’s evolving business landscape [33]. Blockchain technology is particularly beneficial for managing safety in shared-kitchen environments involving multiple supply chains and stakeholders.

2.2. Blockchain-Based Food Safety Management

After the pandemic, food safety gained importance from multiple perspectives, including those of government, researchers, and consumers. Food safety management is evolving toward digital and automation-based methods for assessing food quality, driven by advancements in digital technology [11,34]. Traditionally, food safety management has focused on food traceability, which involves recording and managing information at each stage of the food supply chain—from manufacturing and processing to sales—to provide consumers with data that support safe food choices [12]. If a food safety issue arises, traceability systems enable rapid distribution blocking and recall measures [35]. Food history tracking, which includes process and work information, is generated during food manufacturing and processing and varies for domestic and imported foods. Basic information, such as manufacturing location, production and expiration dates, raw-material origins, and genetically modified organism (GMO) status, is also included. The tracking number on a product allows the verification of its journey from production to consumption [10]. In summary, food history-based safety management requires a process for understanding the components of the food supply chain, food safety management standards, and measurement methods.

The food and distribution industries have recently increasingly adopted blockchain technology to enhance food safety management [36]. International Business Machines (IBM) launched IBM Food Trust, a blockchain-based system for managing food material histories, which provides traceability functions for participants throughout the food supply chain, including cultivation, processing, wholesale, distribution, and manufacturing stages. Kaur et al. (2022) presented a guide to research areas on using blockchain in food safety management, developing a supply chain tracking system that integrates HACCP, blockchain, and IoT for real-time food tracking [37]. Lv et al. (2019) created a blockchain system that supports safety traceability and provides real-time and historical monitoring of temperature and humidity [38]. Similarly, Savina et al. (2020) outlined blockchain requirements to monitor food quality and safety at all production stages, enhancing quality control and traceability. Zheng et al. (2021) proposed a blockchain-based food safety system using IoT for rice traceability [39]. Most previous blockchain-based food safety research has focused on managing single-food ingredients, such as crops. These systems mainly target production and distribution logistics processes for food materials. However, this study focuses on managing safety within shared-kitchen environments, addressing “kitchen safety” to mitigate contamination risks from raw materials through food preparation. Safety management in shared kitchens is especially challenging due to higher sensitivity and complex shared-use factors. This study explores design and environmental factors essential for safety management in shared kitchens involving multiple stakeholders. Existing food safety practices are used as comparative benchmarks to refine approaches for shared kitchens. This study outlines the work process by primary participants and then develops a customized safety management and history tracking system for shared-kitchen settings. In 2022, the Korean Ministry of Food and Drug Safety introduced new safety management certification standards specifically for shared kitchens. Based on existing standards in the food and hospitality industry, these new standards incorporate additional requirements to address the unique aspects of shared kitchens.

Equipment and tools that come into contact with the workplace and food must be managed to minimize cross-contamination, including sanitation checks before and after use. Cross-contamination of transported food and livestock products must be prevented, and storage conditions must comply with temperature control standards by food safety regulations (Ministry of Food and Drug Safety Notice). The importance of safety management in shared kitchens is increasing. If the main participants and work processes for each participant in the shared kitchen are not organized, food safety, including the management of food contamination and safety issues, may not be properly implemented. Therefore, this study specifically selects the safety management roles for each member in the shared kitchen and confirms the work processes and access rights for each member within the chain. This can be said to be an extension of the existing food safety research and focus on methods that can be practically applied.

3. Design of a Blockchain-Based Food Safety System for Shared Kitchens

3.1. Overall System Architecture

The blockchain system architecture proposed in this study is a private network for business applications targeting shared-kitchen operators and users. Here, a private network refers to a type of blockchain restricted to specific, authorized participants, enhancing security and control over access (Figure 1). These business applications execute user actions in the blockchain network through APIs (Application Programming Interfaces), which are tools that allow software programs to communicate with each other. The primary actors within the application are (1) shared-kitchen operators and (2) shared-kitchen users. A shared-kitchen operator manages aspects such as raw-material history and hygiene within the shared kitchen. In contrast, a shared-kitchen user actively participates by handling raw materials and adhering to hygiene protocols.

The REST API (Representational State Transfer API) handles certificate authority (CA) within the blockchain system, which is responsible for managing digital certificates that verify the identities of users and devices to ensure secure communication. A cloud server implements the client node—a specific point in the network where users connect to interact with the blockchain—connected to internal and external databases (DBs). Databases, in this context, refer to structured systems for storing and organizing data essential to the blockchain’s functionality. These DBs are linked based on the four scenario datasets presented in this study. The resulting blockchain-based network system architecture is schematized as follows.

3.2. Functional Requirements

In this chapter, we outline the roles of the main participants in a shared kitchen and the primary safety management responsibilities assigned to each. This study focuses on shared-kitchen safety management in the Korean market, with specific management items adaptable to various market environments. We derive key functional requirements from the Korean Ministry of Food and Drug Safety guidelines. To ensure shared-kitchen safety, the Ministry has defined the roles of facility operators and kitchen users, as shown in

Table 3. Safety management roles and available data items for shared-kitchen members.

Shared-Kitchen Members	Safety Management Role (Provided by the Ministry of Food and Drug Safety of Korea)	Available Data Items Related to Safety Management
Shared-kitchen facility operator	Daily inspection of hygiene management status of kitchen facilities, cooking facilities, etc., by a “sanitation management officer” Management of kitchen facilities, such as water quality inspection, insect repellent, ventilation, refrigeration and freezing, machinery, equipment, etc.	Contracts and all relevant documentation of evidence Manual management by the person in charge of sanitation management (safety management related to facilities and visitors) Internet-of-Things (IoT) sensors in kitchen facility environments (heat and humidity)
Shared-kitchen users	Compliance with the “Shared Kitchen Operation Guidelines” provided by the Ministry of Food and Drug Safety to prevent cross-contamination and ensure the production of hygienic products Management of personal hygiene, such as that of workers and personal cooking equipment, and standards, etc., of manufactured products	Country of origin of food material Details of delivery and delivery of food materials Personal hygiene (whether to wear sanitary clothes, etc.) Order history

. The primary participants in the proposed blockchain system were organized according to the facility standards and compliance requirements for shared-kitchen operators who lease kitchen space and shared-kitchen users who run restaurants by renting designated kitchen areas. Shared-kitchen operators are responsible for the safety of facilities and visitors by appointing a hygiene manager accountable for on-site sanitation. The shared-kitchen operator role includes managing the head office, which oversees operations across multiple branches, and the hygiene manager responsible for safety at individual locations. Shared-kitchen users sign contracts to lease designated kitchen spaces within the shared-kitchen business. They may hire kitchen staff and are responsible for menu creation. Their safety responsibilities include maintaining personal hygiene in the kitchen and ensuring quality control of food ingredients and dishes. Finally, we set functional requirements, specifying actors, functions, and data through workshops with practical and technical experts. In summary, our system design considers varied interests and potential conflicts among stakeholders, addressing these complexities with a blockchain approach that enhances transparency and accountability. The potential conflict lies in the differing priorities between operational efficiency at the head office level and the hygiene managers’ commitment to rigorous, on-the-ground safety practices. Conflicts may arise if operators feel users are not maintaining agreed-upon standards, potentially impacting the reputation and operational integrity of the shared kitchen.

This study established the scope of blockchain management according to responsibility for each type of hygiene. The blockchain system enables responsible parties to register and manage data for safety management items with a high risk of forgery and falsification. Different actors play roles in both utilizing and managing the blockchain system. Shared-kitchen operators manage data structures related to “facility” hygiene, which may be documented by a hygiene manager using a checklist or through technological methods, such as IoT sensors. This includes contract-related documents necessary for agreements between shared-kitchen operators and users. Shared-kitchen users manage data structures related to “food” hygiene, covering food ingredients, cooking, place of origin, entry/exit history, personal hygiene, and order history. Considering these roles, this study analyzes high-priority items for blockchain management, identifying them as on-chain items. It considered the following items in selecting key items in the blockchain: (1) the critical importance of food safety management in shared kitchens, (2) a high risk of data forgery or alteration and substantial safety implications if such issues occur, and (3) the suitability of data capacity for blockchain storage [40].

This study analyzed items requiring rigorous management and defined them as on-chain items following the identification of blockchain-based management targets, as shown in

Table 4. Analysis of available safety management data items and on-chain requirements.

Data Items and Descriptions	On-Chain Necessity Analysis Factors			Decision of On-Chain
	Criticality of Safety Management	Possibility of Forgery	Data Capacity
Contracts and all relevant documentation of evidence (ex.pdf file)	Yes (Y)	Y	↓	Y
Manual management by the person in charge of sanitation management Hygiene control checklist	Y	Y	↓	Y
IoT sensor data—kitchen/refrigerator Time-series temperature and humidity data	Y	Y	↓	Y (hashed)
	Y	Y	↓	Y (hashed)
Country of origin of food materials External DB	Y	No (N)	↓	N
Food material warehousing history System history	Y	Y	↓	Y
Personal hygiene (whether to wear sanitary clothes, etc.) Camera-taken images inside cooking facilities	Y	N	↑	N
Order history management POS instrument recording	N	N	↓	N

. Each standard aligns directly with this study’s objectives, highlighting the importance of using blockchain to confirm the necessity of safety management in shared kitchens and assess the risk of data forgery or manipulation. Consequently, the final selection of on-chain items was determined. This evaluation process involved an internal workshop with blockchain experts, food safety specialists, shared-kitchen professionals, and internal personnel. The final on-chain items identified include contract-related documents, a hygiene management checklist, IoT sensor data, and system record data for food and cooking management. First, contract-related documents were deemed essential for on-chain management due to their high legal significance, adherence to shared-kitchen operational guidelines, susceptibility to forgery, and compatibility with blockchain storage. A hygiene management checklist and IoT sensor data (including time-series temperature and humidity readings) were selected for non-chain management in each kitchen facility. Hygiene checklists, often handwritten, are critical for shared-kitchen hygiene and have manageable data volumes but are prone to forgery, making them suitable for on-chain storage. IoT sensor data monitor kitchen and equipment (e.g., refrigerator) conditions, which is essential for safety management and minimizing vulnerability to forgery. Although the raw sensor data are crucial, they are stored off-chain with only hashed metadata stored on-chain to reduce resource demands and enhance system scalability. Keeping IoT data off-chain reduces resource demands and improves system scalability and throughput. Data such as the country of origin, entry and exit history, personal hygiene, and order history must be managed for food ingredients and cooking items. Among these, the country of origin for ingredients is essential for safety management, as it verifies ingredient sources. However, since government bodies (including the Ministry of Livestock) already manage traceability, the need for additional blocking storage is low. On the other hand, entry and exit records of ingredients are critical for safety management, as forgery and tampering could occur during the recording process. Consequently, entry and exit records were deemed suitable for on-chain management. For personal hygiene, video footage from cooking facilities is crucial for hygiene oversight but impractical for on-chain storage due to the large data volumes. Instead, this information is recorded in a manual checklist stored on-chain to ensure hygiene monitoring. Lastly, POS device records for order details, which businesses and customers can verify, have a low risk of forgery and limited relevance to safety management, making on-chain management unnecessary.

3.3. Use-Case-Based System Design

Based on the primary users for shared-kitchen safety management, key functions for the blockchain system were outlined as use cases, as illustrated in Figure 2. This study aims to implement a blockchain system prioritizing items critical to food history and kitchen safety management, especially those vulnerable to data forgery and manipulation. The system’s main actors include an operator (lessor) and a user (lessee), with the operator further divided into headquarters and managers. The blockchain system enables the reading and writing of contracts, food ingredient records, and kitchen environment data, which are essential on-chain elements for managing safety in shared kitchens. Based on the main users for shared-kitchen safety management, the main functions to be implemented in the blockchain system were diagrammed as use cases, as shown in Figure 3. A detailed description of the created use case is shown in

Table 5. Use case in blockchain systems.

Type of Use Case	Main Contents and Examples
Food materials: registration/modification/deletion of raw materials	Create data: Create data by entering information and history about the food materials to be used Historical inquiry: Inquire and track information related to food materials After the user requests the function to register raw materials, the history of the requested raw materials is checked, and the information is registered
Tracking kitchen environment history: sensor-collected data	Data generation: Real-time measurement and unit-time data for refrigerator temperature (or humidity, voltage, current, etc.) via the temperature measurement sensor of the IoT History check: Inquire and track refrigerator temperature information Real-time temperature and humidity are collected through sensors inside the refrigerator, and then, the temperature and humidity history stored in the block is checked through a history search process
Tracking kitchen environment history: tracking the history	Data generation: Store items, check contents, create completion time for the shared kitchen, and enter checklist data onto the platform History check: Check and track checklist of entered shared-kitchen information The checklist is kept for each shared kitchen and comprises checking time, shared-kitchen number, and items
Registration/modification/deletion of lease agreement	Create data: Create data by entering information and history about the food materials to be used Historical inquiry: Inquire and track information related to food materials Information such as contract date, upload path of original contract file, and contract holder are stored in blocks

below. A detailed explanation of the sequence diagram created based on use cases, such as (1) kitchen interior temperature and humidity history, (2) food material history registration, (3) personal hygiene history tracking, and (4) rental contract tracking, is as follows.

4. Application of Blockchain System

4.1. System Application for a Shared Kitchen

In this section, we aim to develop a blockchain-based use case designed for practical system implementation. This study was conducted using field tests in collaboration with the Wanju County Office, which currently offers shared-kitchen services to lessees and has designated an on-site verification test bed. Because the previously defined on-chain items and the scenarios for each case for use reflect actual shared-kitchen operations, the present research’s validity is substantiated. A sequence diagram was created to illustrate the functions specified in the use case. A sequence diagram—a behavioral diagram—depicts the interactions and the sequence in which they occur among various objects. This approach represents the scenario the existing system will follow. One can easily understand the scenarios using sequence diagrams due to their detailed insights into other systems’ use cases, such as APIs, and model logic, like API calls. Sequence diagrams clarify the order of interactions among actions and actors. In this study, various entities, such as shared-kitchen operators and users, contribute to generating or querying data related to food history and kitchen safety management. Thus, sequence diagrams are utilized here to outline the system’s use plan for blockchain-based history tracking.

For secure and efficient data management, hashing and data capacity management are key considerations. Hashing is a process that converts data into a fixed-length string, or “hash value”, which acts as a unique identifier for the data. In this system, hashing is used to securely store essential records, such as food history, without saving the actual data directly on-chain, thus protecting sensitive information and ensuring data integrity. Additionally, data capacity management is critical because storing large volumes of raw data directly on the blockchain can reduce system efficiency. To manage this, large datasets (e.g., sensor data from kitchen equipment) are stored off-chain, with only the hashed metadata stored on-chain. This approach ensures efficient data retrieval and verification without overwhelming the blockchain’s storage capacity.

First, case-based results are generated to track temperature and humidity history within the kitchen (Figure 4). Data like real-time temperature and humidity readings are collected from IoT devices and stored in the DB. During this stage, the data stored in the DB are blocked; in the blocking process, the data are grouped by date and stored within a block. Each block corresponds to a specific node associated with the measurement location. When a user initiates a history inquiry, the system retrieves and quantifies the data from the blocks, allowing for a detailed review of the refrigerator’s temperature history. Data quantification is necessary because the raw data initially collected from IoT devices must be transformed into structured information, including temperature, humidity, and timestamps, to facilitate historical inquiry.

The second use case illustrates the registration of food material history through a sequence diagram (Figure 5). When a user initiates the registration of a raw material, the system queries the existing history of the requested material, allowing the information to be registered. During the query and registration process, all information related to the raw material is stored in an external DB (open API), so the system retrieves this information from the external DB after the registration request. The linked external DB provides relevant history data when new raw-material information is entered. Additional historical data must be entered manually if no linked food material information is available in the external DB. During the blocking process, the input data are grouped by date and stored within a block. Each generated block is stored in a node associated with the designated location.

The third use case illustrates the history of a kitchen checklist through a sequence diagram (Figure 6). First, shared-kitchen checklist information is stored in a DB, with data grouped and blocked for each shared kitchen. When checklist data are stored in the DB, the creation log and input information for each checklist item are recorded for each shared kitchen. Additionally, checklist data submitted by shared-kitchen users with block generation permissions are stored in a block at defined time intervals. Authorized users can then query and track information about the shared-kitchen checklist. Checklist items are labeled from 1 to N, with check statuses indicated as O or X. The shared-kitchen checklist includes fields for time, kitchen category, kitchen number, and checklist title.

The fourth use case details the contents of the lease contract through a sequence diagram (Figure 7). First, kitchen environment data, collected through IoT sensors and algorithms, are stored in a DB and grouped by time in blocks. When added to the DB, data from the refrigerator, such as temperature and humidity, are measured in real-time by IoT sensors and recorded in a shared-kitchen-specific DB at each time interval. An authorized shared-kitchen user with block creation permissions subsequently stores temperature data on the blockchain platform at set intervals. Authorized users can query and track information related to the refrigerator’s temperature. These data include real-time temperature readings, notifications and alerts, and power usage measurements.

4.2. Data Structure and Function-Based Blockchain

The design specifications of the data structure for blockchain-based data identification and ownership transfer are as follows. The blockchain data structure is presented by categorizing the main participants of the system, the shared-kitchen operator and users, and the shared-kitchen history information. Data on the shared-kitchen operator includes basic information about the shared-kitchen operator, information on facilities within the shared kitchen whose safety management is the responsibility of the shared-kitchen operator, and a hygiene manager who must be appointed when operating the shared kitchen. Data on the shared-kitchen user includes basic information about the business operator who wants to rent from the shared-kitchen operator and information on employees—e.g., the cooks—and menu information. The shared-kitchen history information is composed of food ingredient history information, facility information, and hygiene information and is implemented with a focus on representative examples such as food ingredient history information, facility (refrigeration/freezing) temperature information, and history of wearing hygiene clothing. In addition, the blockchain system includes mandatory documents that must be submitted, such as business registration applications, shared-kitchen use contracts, sanitation manager appointment reports, and liability insurance documents, and thus, the data structure for managing meta information on these documents is designed. This was designed with reference to the food safety management guidelines recommended by the Korean Ministry of Food and Drug Safety and should be reflected in the blockchain platform and network. The specific data structure design details are shown in

Table 6. Design of blockchain-based data structures.

Type	Data Structure	Description (Example)
Shared-kitchen operator (lessor)	OPERATOR_INFORMATION	Operator information (opr1, opr2, opr3 …)
	OPERATOR_EQUIPMENT	Operator equipment information (CAMERA0, 25, 27, 46 …)
	OPERATOR_SANITATION_MANAGER	Operator Hazard Analysis and Critical Control Points leader (admin, user11, user 12 …)
Shared-kitchen user (lessee)	USER_INFO	User information (admin, user1, user2 …)
	USER_WORKER	Kitchen numbers (1000, 1001, 1002 …)
	USER_MENU	Menu of kitchen user (100010120231212000, 100010120231208000, 100010120240221000 …)
Shared-kitchen history information	USER_FOOD_MATERIAL	Food materials in food items (AGRIC, AQUATIC, FOOD|FOOD …)
	HISTORY_EQUIPMENT_TEMPERATURE	Temperature history of the kitchen equipment (20, 21, 18 …)
	HISTORY_SANITARY_CLOTHES	History of wearing sanitary clothing (2022-09-05 1:59:16 AM)
Other (metadata)	HISTORY_HAND_WASH	Hand washing history (2022-08-09 5:30:22 AM)
	HISTORY_FOOD_MATERIAL	Food material history (user food material information storage registration/disposal)
	DOCUMENT_INFORMATION	Document information (meta)

below.

Our blockchain system design includes three primary actors—the Ministry of Food and Drug Safety, shared-kitchen administrators, and shared-kitchen users—with each actor assigned permissions across 4 nodes, totaling 12 nodes. The blockchain model was developed based on an open-source framework “https://github.com/bjpublic/blockchain-python (accessed on 25 July 2023)” and customized to fit the needs of shared-kitchen safety management. The initial node creation achieved an upload speed of 1 s, and the system propagated data across nodes at a rate of four transactions per second. This technical foundation will allow for further developments in smart contract functionality, data encryption, and scalability to enhance system robustness. To ensure data integrity and validate forgery resistance, we engaged an external auditing firm, which confirmed a 100% forgery-free result. The verification process involved three key steps: First, sample transactions were selected, and transaction records stored on two randomly chosen nodes were compared for consistency. Second, the hash values of sampled transactions from two random nodes were compared to detect any discrepancies. Finally, random hash values were generated, and input tests were conducted to simulate potential forgery scenarios, verifying the system’s ability to detect unauthorized alterations. These validation steps confirm that our blockchain system effectively resists forgery, supporting secure and reliable safety management in shared kitchens. Currently, no systematic, blockchain-based operational management system exists for shared-kitchen safety, making our proposed approach the first of its kind. We experimentally validated the system’s forgery resistance, demonstrating its effectiveness in reducing forgery and alteration risks.

5. Discussion

Among the various types of blockchains, the central authority owns all authorities on block access (creation, removal, inquiry, etc.) in the private system. Conversely, a consortium-type blockchain system can set block rights depending on the participant group to which it belongs. When managing the operation and management of a shared kitchen through a private blockchain, the blockchain must be operated and managed by relying on one central institution. However, the system to be developed in this study includes complex participants, such as government agencies for central management, managers within the headquarters and branches of shared-kitchen operating franchises, and individual companies located in shared kitchens. In this study, it is necessary to assign different management responsibilities and authorities to each participant. In other words, it is necessary to differentiate and design the scope and function of the blockchain access rights according to the composition of the complex participants. Considering the characteristics of this project, there are operational difficulties when designing it as a private blockchain through the designation of a single central management agency. Therefore, this chapter discusses ways of expanding the blockchain network in the form of a consortium.

A consortium-type blockchain can be designed that considers participant groups in a blockchain-based intelligence system for shared-kitchen operation and food safety management. Centered around the Ministry of Food and Drug Safety, which is the central management agency, the proposed system consists of a large consortium that operates franchise-type shared kitchens, a small consortium that operates shared-kitchen branches, and a small consortium that operates individually. The central management agency performs comprehensive management functions, such as operation registration and the management of shared kitchens, and plays a role in managing participants in the consortium blockchain. A large consortium performs the function of registering and managing shared-kitchen branches. The proposed consortium-type blockchain system design plan is shown in Figure 8.

As the proposed blockchain system is designed for shared-kitchen networks, scalability in high-data-volume scenarios is essential. Large-scale shared-kitchen networks generate substantial data through various IoT sensors, user interactions, and transactional records. To manage this, the system employs off-chain storage for large datasets (e.g., sensor data), where only hashed metadata are stored on-chain. This approach ensures that the blockchain remains efficient and responsive even in high-data environments by minimizing on-chain data storage and prioritizing essential data for blockchain storage. This adaptability enables the system to scale effectively without compromising data integrity or transaction speed.

While this study focuses on the application of a blockchain-based food safety management system in South Korea, the system can be adapted to meet food safety standards in other regions, such as the United States and Europe. In the U.S., the FDA’s Food Safety Modernization Act (FSMA) emphasizes traceability and prevention of foodborne illness, goals like those outlined in this study [8]. Blockchain can enhance transparency and traceability in compliance with FSMA by providing tamper-resistant records of food handling and storage. In Europe, regulations under the European Food Safety Authority (EFSA) require robust traceability systems and high standards of hygiene, both of which can be strengthened by this blockchain-based approach [35]. By adapting the system’s parameters to reflect region-specific regulatory requirements, this blockchain framework could provide a unified approach to food safety management in shared kitchens globally.

6. Conclusions

In this study, we designed and proposed a blockchain-based system for implementing smart traceability and food safety management in shared kitchens, a recently emerging sector within the food technology industry. Significant actors and their roles were defined to establish the functional requirements for the blockchain system. We designed use cases and architectures for the blockchain-based food safety management system. We proposed a scenario and data structure for system implementation based on these. Additionally, we discussed extending the system to a consortium network, considering the stakeholder groups involved in shared kitchens.

The proposed blockchain system demonstrates its potential applicability in shared kitchens. While designing the blockchain network, we examined functional requirements, including system actors, relationships, and roles. Specific use cases and detailed data structures were developed to address the high risk of forgery, data alteration, and management challenges. This study offers a practical contribution toward systematic safety management in shared kitchens. Blockchain technology can support innovation in the food technology industry and, economically and socially, it can help minimize consumer harm from food counterfeiting, promoting stable market growth by addressing shared-kitchen safety management issues. The blockchain-based food traceability system, combined with big data for managing shared-kitchen safety, is expected to enhance the social safety network as online food and ingredient shopping expands. However, further updates could improve the system’s efficiency. This study focused on shared kitchens in South Korea, where head offices and branches typically organize operations; the blockchain network can be adapted to suit regional and national contexts. Additionally, a platform could be developed to facilitate data transactions among diverse stakeholders in the shared-kitchen sector. Specifications and requirements should be refined based on real-world applications. First, this study focused on shared kitchens in Korea, where most shared kitchens are operated at their headquarters. Blockchain networks can be modified to fit geographical and national situations. Our study only discussed the applicability in Korea, but specific safety management issues may vary depending on the food safety guidelines and safety management methods in each country. Although detailed requirements and guidelines may change, they are managed in an integrated manner, and shared kitchens are managed as a network and are block-based to reduce security issues. This blockchain-based system is not only applicable to the Korean market but also holds significant potential for adaptation to food safety standards in regions such as the U.S. and Europe. Both regions have stringent food safety regulations that prioritize traceability and data integrity. The system’s modular design allows it to be tailored to specific regulatory requirements, suggesting that blockchain technology could serve as a universal foundation for shared-kitchen safety across diverse regulatory environments. Considering international applicability, the manual can be modified by referring to safety management issues and food safety guidelines that vary by country. The food technology industry, including shared kitchens, continues to develop technologies for use, such as blockchain. Food safety management is a problem that continuously emerges as the modern food industry develops. If a safety management system using blockchain and a platform based on it are developed in the system, the food industry can be safely and accurately managed, and much development can be achieved in terms of technology and society.