Distributed Ledger Technology Applications in Food Supply Chains: A Review of Challenges and Future Research Directions

Round 1

Reviewer 1 Report

Comments on the manuscript entitled "Distributed ledger technology applications in food supply chains: a review of challenges and future research directions":

- It is convenient to make a table with all the acronyms of the work
- Is it necessary to make a subsection only in the Intro, such as "1.1. Emerging Technologies for Sustainable Development Goals"? If you need to subdivide, the reason is that at least there will be 2 subsections
- Lines 81-88: You indicate that "... with several of them directly affected by traceability of FSCs: good health and wellbeing (SDG 3), decent work and economic growth (SDG 8), industry and infrastructure (SDG 9) and responsible consumption and production (SDG 12). Additionally, clean water and sanitation (SDG 6) and climate action (SDG 13) are affected ... ". How have you detected that these SDGs are influenced? Only for ref. 7?
- Line 128: "Based on the research objectives ..." Which ones? Where are they expressed?
- Lines 203-207: It is not (;), but (.).
- Lines 208-210: "Classification of papers was carried out according to authors’ understanding and interpretation of findings, considering relevance and technological contribution of the analyzed publications ". Here you need to include previous works that help you classify and interpret them
- Figure 4: It does not seem relevant to include this image, since it is not indicated with which software it was made and why it stands out some words over others
- Table 3: How have you detected them? With what software?
- Table 4: How have you detected these groups?
- Figure 6. Okay!
- What do the potential research agendas (PRG) mean?

Author Response

Response to Reviewer 1.

- It is convenient to make a table with all the acronyms of the work

List of abbreviations was added, please see lines 767-794.

 

- Is it necessary to make a subsection only in the Intro, such as "1.1. Emerging Technologies for Sustainable Development Goals"? If you need to subdivide, the reason is that at least there will be 2 subsections

As suggested, the subsection was removed. Initially, the subsection was added to highlight the contribution of the manuscript towards the six Sustainable Development Goals (SDGs) of the United Nations and to delineate the strategic SDGs, which are to be addressed in the section “Implications for Future Research Directions”.

 

- Lines 81-88: You indicate that "... with several of them directly affected by traceability of FSCs: good health and wellbeing (SDG 3), decent work and economic growth (SDG 8), industry and infrastructure (SDG 9) and responsible consumption and production (SDG 12). Additionally, clean water and sanitation (SDG 6) and climate action (SDG 13) are affected ... ". How have you detected that these SDGs are influenced? Only for ref. 7?

The citations were added, the wider explanation of SDGs links is provided in the following paragraphs.

 

- Line 128: "Based on the research objectives ..." Which ones? Where are they expressed?

The objectives were highlighted, please see lines 119-124:

• “The challenges of scalability, security and privacy and practices to address them are described in detail;
• Suggestions for future research directions are provided, with wider interpretation of their relevance to the SDGs [8] and contribution towards more transparent, traceable, and sustainable FSCs.”

 

 

- Lines 203-207: It is not (;), but (.).

This aspect was also considered.

 

- Lines 208-210: "Classification of papers was carried out according to authors’ understanding and interpretation of findings, considering relevance and technological contribution of the analyzed publications ". Here you need to include previous works that help you classify and interpret them

We followed the approach of Kamble et al. (2020), which classified the six types of supply chain resources: financial, physical, human (managerial and technical skills), organizational, technological and intangible (reputation, brand recognition, data-driven culture and organizational learning). Their approach classified 84 papers for a different category. They proposed a framework which “identifies supply chain visibility and supply chain resources as the driving source for developing data analytics capability and achieving the sustainable performance”. Since analyzing the resources is critical to adopt novel technologies, according to Angelis et al. (2019), the classification was closely fitting to the scope and analysis of our paper. Since these resource types closely correlated with our identified targets, i.e., current challenges in ongoing research, we applied this approach for our classification. Additionally, we added two more categories: environmental and data-related. The classification and allocation of challenges to different groups was done manually by the authors by thematically interpreting the identified challenges into each category.

The approach of Kamble et al. (2020) is mentioned in the line 445.

 

- Figure 4: It does not seem relevant to include this image, since it is not indicated with which software it was made and why it stands out some words over others

- Table 3: How have you detected them? With what software?

The software, which was used to identify the keywords (challenges) was ATLAS.ti. The software was used to visualize the top 25 keywords related to challenges (Figure 4) and to identify the most frequent occurrences of challenges (Table 2). The ATLAS.ti software is mentioned in the line 234 and 239.

 

- Table 4: How have you detected these groups?

As mentioned in the previous point, the classification was adapted from the approach of Kamble et.al (2020), who classified supply chain resources into six categories. We additionally added two more categories: data-related and environmental, since both were identified as standalone categories of challenges, that have to be tackled and addressed independently. The approach is mentioned in line 445.

 

- What do the potential research agendas (PRG) mean?

The “potential research agendas” was renamed to “Future Research Directions” or FRDs and are referred to similarly throughout the paper. The directions represent potential targets for future research, which were identified from the analyzed literature.

Reviewer 2 Report

The paper is interesting and well organised.
My only concern is about the missing review of the literature after june 2020.
I suggest to insert some papers because 6 months are a lot in a period so intensive for papers' production like the one of the pandemic.

Author Response

Response to Reviewer 2.

• My only concern is about the missing review of the literature after june 2020.
  I suggest to insert some papers because 6 months are a lot in a period so intensive for papers' production like the one of the pandemic.

The publications until the end of 2020 were added to our analysis. From June 2020 until December 2020, 24 more publications were added. The same analysis was carried out with the new papers: analysis of content, identification of challenges and future research directions. Data, figures and tables were updated with the analysis of newly added publications. The top identified challenges of scalability, security and privacy were described in detail with the way they were tackled in literature.

Reviewer 3 Report

Keywords: you need to use the full-phrase in addition to the abbreviation provided.

Introduction. This section should be modified to include the following paragraphs, without a sub-section; background, problem statement, state-of-research, critical review of the existing review papers on the topic (there are 6-7), highlighting your contribution, and the manuscript outline.

Please provide a reference to lines 31 and several references to line 53 (you mentioned widely, so either cite a review paper or several of the most recent ones).

Completely rephrase the paragraph starting in line 67.

Results and discussion. From the challenges of applying DLT and IoT in FSCs, why only three of them are discussed? you need to improve your justification.

The enablers of applying DLT and IoT Implementation in FSCs should also be included in your analysis.

Please manually include the publications until the end of 2020 in parts of your analysis. I understand that your research was completed earlier, but a significant number of papers have been published in the past months. Besides, this manuscript will be published in mid-2021 and it makes no sense to bound your analysis to about a year earlier.

Conclusions. This section should be re-written; conclusions should be self-sufficient and brief. Try to re-structure your conclusions in three paragraphs: background and contribution, the major findings and observations, and the MAJOR insights for future research directions. You also need to clarify the limitation of your research and provide insights for future contributions that address the limitation.

Overall, my major concerns are as follows:

• There are several review works closely relevant to the subject some of which are not cited at all. You need to provide a table or a critical discussion to convince me and your potential readers that your review paper provides something new.
• The content should be updated to include the published works after June 2020.
• Analysis of enablers would provide additional value to your review work.

Author Response

Response to Reviewer 3.

• Keywords: you need to use the full-phrase in addition to the abbreviation provided.

Full-phrase keyword was added.

• Introduction. This section should be modified to include the following paragraphs, without a sub-section; background, problem statement, state-of-research, critical review of the existing review papers on the topic (there are 6-7), highlighting your contribution, and the manuscript outline.

The heading (sub-section) was removed. The background is described in lines 31-68 and 77-81, describing current challenges and issues in food supply chains (FSCs), such as food fraud, food waste, lack of digitalization and records. The challenges and globalization of the FSCs are driving the digitalization initiatives with novel technologies, among which are the Internet of Things (IoT), distributed ledger technologies (DLTs) and blockchains. Potentials of integrating the technologies are described such as improved cyber-security, preventing food fraud, cost and time reduction, improved data continuity and trust among stakeholders and consumers in FSCs. The importance of traceability of FSCs is described.

Problem statement is described in lines 109-111 and 77-81, highlighting the risks associated with lack of transparency and traceability in FSCs and early development stage of DLT solutions in FSCs.

State-of-research is described in lines 82-108, describing the areas and potentials DLTs can provide in FSCs, including improved sustainability and addressing the Sustainable Development Goals (SDGs) of the United Nations. Previous studies on DLT potentials for sustainability and SDGs are described.

The review papers are additionally cited in lines 111-117, outlining the importance of the challenges of scalability, privacy and security in ongoing research, the review papers that already addressed challenges of DLT adoption in FSCs, applications and suggestions for future research.  On top of that, the key contributions and objectives of our paper are highlighted in the lines 120-124:

• “The challenges of scalability, security and privacy and practices to address them are described in detail;
• Suggestions for future research directions are provided, with wider interpretation of their relevance to the SDGs [8] and contribution towards more transparent, traceable, and sustainable FSCs.”

The manuscript outline is described at the end of the introduction section, in lines 125-130.

• Please provide a reference to lines 31 and several references to line 53 (you mentioned widely, so either cite a review paper or several of the most recent ones).

The citations were added more widely in the first paragraph, describing clearly which aspects were cited by which source. The modifications were made in the lines 31-51 and 54-68.

• Completely rephrase the paragraph starting in line 67.

The paragraph in lines 69-76 was rephrased, describing the term DLT and basic description of the functionality, the references stayed the same.

• Results and discussion. From the challenges of applying DLT and IoT in FSCs, why only three of them are discussed? you need to improve your justification.

The highlight on the top three challenges was provided, describing recent review papers highlighting the importance of scalability, privacy and security of DLT solutions in FSC domain in ongoing research. The ongoing research highlighted the importance of the three challenges, current ongoing efforts and that the state of existing solutions is still not good enough to be considered for wide adoption. The most prominent publications that highlighted these challenges were added. The following references were added:

(Please see lines 117, 195, and 243).

Qian, J., Dai, B., Wang, B., Zha, Y., & Song, Q. (2020). Traceability in food processing: Problems, methods, and performance evaluations-a review. Critical Reviews in Food Science and Nutrition, 1–14. https://doi.org/10.1080/10408398.2020.1825925

Lin, W., Huang, X., Fang, H., Wang, V., Hua, Y., Wang, J., Yin, H., Yi, D., & Yau, L. (2020). Blockchain Technology in Current Agricultural Systems: From Techniques to Applications. IEEE Access, 8, 143920–143937. https://doi.org/10.1109/ACCESS.2020.3014522

Katsikouli, P., Wilde, A. S., Dragoni, N., & Høgh-Jensen, H. (2021). On the benefits and challenges of blockchains for managing food supply chains. Journal of the Science of Food and Agriculture, 101(6), 2175–2181. https://doi.org/10.1002/jsfa.10883

Xu, Y., Li, X., Zeng, X., Cao, J., & Jiang, W. (2020). Application of blockchain technology in food safety control：current trends and future prospects. Critical Reviews in Food Science and Nutrition, 1–20. https://doi.org/10.1080/10408398.2020.1858752

Torky, M., & Hassanein, A. E. (2020). Integrating blockchain and the internet of things in precision agriculture: Analysis, opportunities, and challenges. Computers and Electronics in Agriculture, 178(2), 105476. https://doi.org/10.1016/j.compag.2020.105476

 

• The enablers of applying DLT and IoT Implementation in FSCs should also be included in your analysis.

The enablers and value drivers were added in section 3.4, see lines 508-514. The following enablers were added: “customer satisfaction, risk reduction, improvement of safety and quality of food, fraud detection, reduction of paperwork, provenance tracking, real-time transparency, improved systems and data security and government regulations”.

• Please manually include the publications until the end of 2020 in parts of your analysis. I understand that your research was completed earlier, but a significant number of papers have been published in the past months. Besides, this manuscript will be published in mid-2021 and it makes no sense to bound your analysis to about a year earlier.

The publications until the end of 2020 were added to our analysis. From June 2020 until December 2020, 24 more publications were added. The same analysis was carried out with the new papers: analysis of content, identification of challenges and future research directions. Data, figures and tables were updated with the analysis of newly added publications. The top identified challenges of scalability, security and privacy were described in detail with the way they were tackled in literature.

Conclusions. This section should be re-written; conclusions should be self-sufficient and brief. Try to re-structure your conclusions in three paragraphs: background and contribution, the major findings and observations, and the MAJOR insights for future research directions. You also need to clarify the limitation of your research and provide insights for future contributions that address the limitation.

The section was shortened and rewritten, with several summary highlights moved to section 3.4.

The background and main contribution are described in lines 707-713. The major findings and observations are described in lines 707-709, 714-740, summarizing major challenges of DLT-IoT implementation in FSCs, describing key findings related to the lack of regulations, interoperability, issues of high cost of implementation and energy consumption, the need of novel approaches to automatically measure food quality. Major insights for future research directions are mentioned in lines 741-745 and 710-713, including combination of different emerging technologies for increased value, need of empirical investigations, contributions towards sustainability of FSCs and the six strategic SDGs. The limitations of research are mentioned in lines 700-702.

Round 2

Reviewer 1 Report

Comment on "Distributed ledger technology applications in food supply chains: a review of challenges and future research directions":

- How do you justify having chosen the concepts DLT and ‘blockchain’, that is, blockchain OR distributed ledger? We know that they are often used as synonyms (they share a conceptual origin) when they are not. This decision leads to distorting the sample and can be considered a serious error.
- Why do you include Figure 4 if you provide the same (and more) info in Table 2?

Author Response

- How do you justify having chosen the concepts DLT and ‘blockchain’, that is, blockchain OR distributed ledger? We know that they are often used as synonyms (they share a conceptual origin) when they are not. This decision leads to distorting the sample and can be considered a serious error.
Thank you very much for your comment. Throughout the paper, the concepts of “DLT” and “blockchain” are considered as two independent, different and innovative terms. Since in literature, both terms are used and, as we know, they are, not synonyms, we included both terms in our search. Several papers specifically used the term “distributed ledger technology” or “distributed ledger” in abstract or throughput the paper, such as Lagutin et al. (2019) (DLT mainly), Kim et al. (2018) (DLT and blockchain terms), Chandra et al. (2019) (DLT and blockchain terms), Roeck et al (2019) (DLT mainly), Katsikouli et al. (2020) (DLT and blockchain terms).

However, very often the terms of DLT and blockchain are used as synonyms, since they share some common characteristics, such as distribution of data and computation and decentralization, but of course both concepts have different characteristics, such as blockchain having a block-based data storage mechanism and offering the possibility of integrating smart contracts or different consensus algorithms. DLT, however, is a generic term, which specifies a distributed and decentralized methodology used in a specific implementation, such as IOTA, BigchainDB or IPFS, and potentially using different underlying data structures as well, such as directed acyclic graph (DAG), distributed hash table (DHT), etc. Blockchain, however, is a very specific peer-to-peer data structure, which supports autonomous and decentralized operation and properties related to data immutability. Ethereum or Hyperledger are some of the implementations of blockchain, that are currently in use (Karaarslan & Konacakli, 2020).

There are, several architectural challenges of blockchain implementations, such as low transaction speed and volume, storage limitations and scalability (Karaarslan & Konacakli, 2020).

The solutions using directed acyclic graph and distributed hash table data structures (such as IOTA Tangle, Hashgraph), for instance, can be considered to address the limitations and challenges of blockchain, mentioned earlier. These solutions, however, do have decentralized computation and control properties as well, but different data structures are involved, and these solutions can also be considered as DLT solutions (Karaarslan & Konacakli, 2020). The comparative outline of these examples is provided in Table 1, below.

Therefore, DLT and blockchain concepts technically and architecturally are different and should never be used as synonyms. When referred to blockchain concept, a specific data structure and properties will be assumed, when referred to DLT concept, a more generalized assumption of properties can be considered, including blockchain, however, but not limited to blockchain specifics and properties (Karaarslan & Konacakli, 2020). Blockchain technology, however, assumes application of several specific functionalities, such as the use of smart contracts, mining of blocks, consensus mechanisms or use of tokens, therefore, using “blockchain” term alone would be limiting the complex research on distributed ledger technologies.

Table 1 – Comparative outline of DLT and blockchain solutions (Karaarslan & Konacakli, 2020)

DLT solutions	Blockchain solutions
IOTA Tangle, Byteball - directed acyclic graph (DAG), Hashgraph - directed acyclic graph (DAG), Holochain - distributed hash table (DHT)	Hyperledger Fabric, Ethereum – peer-to-peer

An overview of DLT solutions is provided in Table 2, below, cited from Karaarslan & Konacakli, 2020.

Table 2 – Overview of DLT solutions (from Karaarslan & Konacakli, 2020).

As it can be seen from Table 2, DLT combines multiple technologies and solutions, of different data structures, and blockchain is one of the specific implementations.

In our formulation, we specified the differences of DLT and blockchain and why we mainly refer to “DLT” formulation (since it combines the properties of decentralization and distribution, etc.).:

“DLT is a term used to represent a digital network of distributed models, consisting of blockchain-based ledgers, and collaborating on shared tasks and activities. Blockchain technology is a data structure, composed of “blocks” that are cryptographically linked together in a chained sequence using cryptographic hashes, secured against manipulations [8, 12]. Due to wider functionality, DLT is a commonly used term for a computer-based system consisting of distributed ledger-based data structures, which can provide increased levels of trust, service availability, resiliency, and security of digital systems, as well as distributed storage, computation, and control [12].”

Since some of the papers mainly used the term “DLT” or “distributed ledger technology” or “distributed ledger”, we included the “distributed ledger” as well in our search. However, as we can see from our analysis, the papers that specifically referred to the term “distributed ledger technology” always assumed and considered blockchain in research as well, so including this term was not leading to other research topics. The papers that mainly used the term “distributed ledger” still included the mentions of blockchain technology in text, as “one of the existing DLTs”, but mostly referred to “DLT” in abstract or throughout the text, so we considered it to be important to include both terms in our search with the Boolean “OR” clause.

In our search (as it is mentioned in section 2. Research methodology), the keywords of “blockchain” OR “distributed ledger” AND “food supply chain” were used, either in abstract or in full text search (please see Table 1 for details). Therefore, in our opinion, including either of the keywords and not both would result in losing some of the papers that we have included in our analysis.

 

References

• Chandra, G. R., Liaqat, I. A., & Sharma, B. (2019, February - 2019, February). Blockchain Redefining: The Halal Food Sector. In 2019 Amity International Conference on Artificial Intelligence (AICAI) (pp. 349–354). IEEE. https://doi.org/10.1109/AICAI.2019.8701321
• Karaarslan, E., & Konacaklı, E. (2020). Data Storage in the Decentralized World: Blockchain and Derivatives. Advance online publication. https://doi.org/10.26650/B/ET06.2020.011.03
• Katsikouli, P., Wilde, A. S., Dragoni, N., & Høgh-Jensen, H. (2021). On the benefits and challenges of blockchains for managing food supply chains. Journal of the Science of Food and Agriculture, 101(6), 2175–2181. https://doi.org/10.1002/jsfa.10883
• Kim, M., Hilton, B., Burks, Z., & Reyes, J. (2018, November - 2018, November). Integrating Blockchain, Smart Contract-Tokens, and IoT to Design a Food Traceability Solution. In 2018 IEEE 9th Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON) (pp. 335–340). IEEE. https://doi.org/10.1109/IEMCON.2018.8615007
• Lagutin, D., Bellesini, F., Bragatto, T., Cavadenti, A., Croce, V., Kortesniemi, Y., Leligou, H. C., Oikonomidis, Y., Polyzos, G. C., Raveduto, G., Santori, F., Trakadas, P., & Verber, M. (2019, June - 2019, June). Secure Open Federation of IoT Platforms Through Interledger Technologies - The SOFIE Approach. In 2019 European Conference on Networks and Communications (EuCNC) (pp. 518–522). IEEE. https://doi.org/10.1109/EuCNC.2019.8802017
• Roeck, D., Sternberg, H., & Hofmann, E. (2020). Distributed ledger technology in supply chains: a transaction cost perspective. International Journal of Production Research, 58(7), 2124–2141. https://doi.org/10.1080/00207543.2019.1657247

 

- Why do you include Figure 4 if you provide the same (and more) info in Table 2?

Thank you for the suggestion. We followed the criteria to add keywords with at least 5 occurrences in Table 2. Since the figure has some repetitive content and doesn’t provide much value and novelty to existing text and elaborations, it was decided to remove the Figure 4.

Author Response File: Author Response.pdf

Reviewer 3 Report

1. The background part of the introduction is weak in terms of citation. In the first two paragraphs, you repeatedly cited the same articles (References 1-3). You'd better add more recent citations and from reputed journals. Among other changes, I suggest adding the following sentence at the end of line 62 (Page 2): "Blockchain can benefit production planning and scheduling across supply chains (Ying et al., 2020)."

Ref: Ying, Kuo-Ching, et al. "Supply chain-oriented permutation flowshop scheduling considering flexible assembly and setup times." International Journal of Production Research (2020): 1-24.

You need to put more effort into improving the introduction section.

2. You dismissed my comment on adding a table to compare the contributions of your work with those of the existing review papers on this subject. You can consider several fields in the table and mark the differences. Besides, you missed citing two of the recent relevant works. 

3. I recommend the authors highlight the contributions in accordance with the research questions. For this purpose, you need to move the RQs to the introduction section.

4. The conclusions section should be improved by adding the limitations of your research and suggesting directions for future SLR.

Author Response

1. The background part of the introduction is weak in terms of citation. In the first two paragraphs, you repeatedly cited the same articles (References 1-3). You'd better add more recent citations and from reputed journals. Among other changes, I suggest adding the following sentence at the end of line 62 (Page 2): "Blockchain can benefit production planning and scheduling across supply chains (Ying et al., 2020)."

Ref: Ying, Kuo-Ching, et al. "Supply chain-oriented permutation flowshop scheduling considering flexible assembly and setup times." International Journal of Production Research (2020): 1-24.

You need to put more effort into improving the introduction section.

Thank you very much for your comment, we have put more effort into the introduction section and added more references, please see the first two paragraphs (lines 31-78). Additionally, as it was suggested, we restructured the introduction section, summarizing the barriers and current state of research (lines 115-126), current problems in FSCs and issues of lack of transparency (lines 32-58), benefits and potentials of IoT, blockchain and DLT for FSCs (lines 59-78, 97-114), contribution of DLTs for SDGs of the UN (lines 89-114). We included relevant review papers in the background (31-58), current state of research (lines115-126) and contribution towards SDGs (lines 97-114). From the current state of research, it can be seen that the practical details of scalability, security and privacy have not been described in detail previously, and, additionally, wider interpretation of relevance for SDGs is provided, linking future research directions to 6 strategic SDGs, thereby contributing towards transparency, traceability and sustainability of FSCs. From our analysis, it can be seen that this study has not been carried out previously and therefore this paper provides valuable new insights.

Recent relevant publications were additionally added to the introduction section: Behnke and Janssen (2020), Köhler and Pizzol (2020), Rogerson and Parry (2020), Ying et al. (2020).

2. You dismissed my comment on adding a table to compare the contributions of your work with those of the existing review papers on this subject. You can consider several fields in the table and mark the differences. Besides, you missed citing two of the recent relevant works. 

• There are several review works closely relevant to the subject some of which are not cited at all. You need to provide a table or a critical discussion to convince me and your potential readers that your review paper provides something new.
• The content should be updated to include the published works after June 2020.
• Analysis of enablers would provide additional value to your review work.

Thank you for your reminder. The comments were addressed in the paper, however they were not summarized in the response to reviewers comments previously. A table and summary of analyzed papers is provided in the section “3.4 Summary and Outlook of Challenges and Enablers of DLT adoption”. The section summarizes the practices to address the challenges of scalability, security and privacy of blockchain, DLT and IoT solutions. Additionally, other highlighted challenges were summarized in this section, such as regulatory and standardization, interoperability, digitalization barriers, food legislation, data and infrastructure ownership, data tampering and incredibility, and resistance to implementation among FSC stakeholders. The table summarizes the practices described in our paper to address the challenges of scalability, security and privacy, please see below (Table 4).

Challenges	Solutions	References
Scalability	IPFS for storing data off-chain	food and agri-food [47, 48, 51], agriculture [20, 68], rice [50], food trade [19]
	sharding	food [46], trade [37]
	BigchainDB	food [52]
	Proof-of-Supply-Chain-Share	e-commerce [42]
	Lightning network	food [53]
	Lightweight data structures, Delegate Proof-of-Stake, Distributed Time-based Consensus, DoubleChain, grouping nodes into clusters	agriculture [20]
	Two-level blockchain	agri-food [54]
Security	Data access restriction	food [46], agri-food [54]
	Proof-of-Supply-Chain-Share, blockchain vaporization	food [42]
	Proof-of-Authority	trade [37]
	Proof-of-Object	food [59]
	Product serialization, path-based fund transfer protocol	perishable food [61]
	Ellipse Curve Cryptography, Diffie-Hellman, RSA, secure protocols (Telehash, Whisper)	food trade [19], agriculture [20]
	Lightweight data structures, proxy encryption	agriculture [20]
	Interledger, consortium blockchain	food [62]
Privacy	Peer Blockchain Protocol	trade [37]
	Interledger blockchain	food [62]
	Access rights restriction, two-way coding scheme	grain [63]
	On-chain and off-chain data storage	food trade [19], food [51]
	Improved partial blind signature, proxy encryption	agriculture [20]
	Zero-knowledge proof encryption	agri-food [54]

The review papers that we have analyzed and the review papers which were additionally included in the introduction section did not provide a fully comprehensive summary of practices to address the scalability, security, and privacy challenges (Rejeb et al.,2020; Qian et al.,2020; Torky et al.,2020; Lin et al., 2020; Katsikouli et al., 2020). The detailed elaboration of solutions and the table with the summary is, therefore, new and relevant for ongoing research. Another major contribution is the link of future research directions to the SDGs of the UN, in particular, it has been elaborated that blockchain and DLT implementation in FSCs can potentially address 6 strategic SDGs, thereby improving sustainability, traceability and transparency of FSCs. The 6 strategic SDGs are: good health and wellbeing, decent work and economic growth, industry and infrastructure, responsible consumption and production, clean water and sanitation and sustainable cities and communities. The potential future research directions and links to the SDGs are summarized in the section “4. Implications for Future Research Directions”.

The enablers were additionally specified in the section “3.4 Summary and Outlook of Challenges and Enablers of DLT adoption”, please see the text block below, also in lines 513-523:

“Several investigations were carried out to identify various enablers and value drivers of blockchain and DLT adoption in FSCs [78, 79]. The key enablers identified were customer satisfaction, risk reduction, improvement of safety and quality of food [69, 79], fraud detection, reduction of paperwork, provenance tracking, real-time transparency [69, 79], improved systems and data security and government regulations [79]. Depending on the sought value, available resources, feasibility of implementation [30] and various blockchain maturity levels and development stages (1.0, 2.0., 3.0) should be considered when deciding on DLT adoption [15, 39, 78]. Several techno-economic factors, such as disintermediation, traceability, and price, were highlighted as the most important factors that can influence stakeholders’ adoption decisions [77].”

Additionally, as it was mentioned in the previous comment, recent relevant publications were additionally added to the introduction section, future research directions and conclusion sections in the paper: Behnke and Janssen (2020), Köhler and Pizzol (2020), Rogerson and Parry (2020), Ying et al. (2020).

References

• Behnke, K., & Janssen, M.F.W.H.A. (2020). Boundary conditions for traceability in food supply chains using blockchain technology. International Journal of Information Management, 52(9), 101969. https://doi.org/10.1016/j.ijinfomgt.2019.05.025
• Köhler, S., & Pizzol, M. (2020). Technology assessment of blockchain-based technologies in the food supply chain. Journal of Cleaner Production, 269, 122193. https://doi.org/10.1016/j.jclepro.2020.122193
• Rogerson, M., & Parry, G. C. (2020). Blockchain: case studies in food supply chain visibility: lal. Supply Chain Management: An International Journal, 25(5), 601–614. https://doi.org/10.1108/SCM-08-2019-0300
• Ying, K.-C., Pourhejazy, P., Cheng, C.-Y., & Syu, R.-S. (2020). Supply chain-oriented permutation flowshop scheduling considering flexible assembly and setup times. International Journal of Production Research, 8(5), 1–24. https://doi.org/10.1080/00207543.2020.1842938
• Rejeb A, Keogh JG, Zailani S, Treiblmaier H, Rejeb K. Blockchain Technology in the Food Industry: A Review of Potentials, Challenges and Future Research Directions. 2020;4:27. doi:10.3390/logistics4040027.
• Qian J, Dai B, Wang B, Zha Y, Song Q. Traceability in food processing: problems, methods, and performance evaluations-a review. Crit Rev Food Sci Nutr. 2020:1–14. doi:10.1080/10408398.2020.1825925.
• Lin W, Huang X, Fang H, Wang V, Hua Y, Wang J, et al. Blockchain Technology in Current Agricultural Systems: From Techniques to Applications. IEEE Access. 2020;8:143920–37. doi:10.1109/ACCESS.2020.3014522.
• Katsikouli P, Wilde AS, Dragoni N, Høgh-Jensen H. On the benefits and challenges of blockchains for managing food supply chains. J Sci Food Agric. 2021;101:2175–81. doi:10.1002/jsfa.10883.
• Torky M, Hassanein AE. Integrating blockchain and the internet of things in precision agriculture: Analysis, opportunities, and challenges. Computers and Electronics in Agriculture. 2020;178:105476. doi:10.1016/j.compag.2020.105476.

 

3. I recommend the authors highlight the contributions in accordance with the research questions. For this purpose, you need to move the RQs to the introduction section.

The RQs were moved to the introduction section, after stating the research contributions and objectives.

4. The conclusions section should be improved by adding the limitations of your research and suggesting directions for future SLR.

The limitations of research have been modified, with statement added at the end of conclusion section (please see the text block below):

“Further research should focus on considering other related supply chains, such as textile, e-commerce, food trade, agriculture, agri-food, perishable food, frozen food, processed food, global and local retail industries, packaging, and grocery networks, as well as investigating the impacts of other emerging technologies, mentioned in this study, on sustainability, transparency and traceability of FSCs. Furthermore, other highlighted challenges, presented in this study, such as regulatory, standardization and interoperability issues, should be addressed in more detail.”

Relevant and neighboring areas to FSCs, such as textile, food trade, perishable food, frozen food, e-commerce, grocery chains, retail, and packaging have been added. Since FSCs are complex with many links to other supply chains, these areas have been identified as closely relevant and contributing to FSC research topic. Investigating the impact of other emerging technologies, such as AI, big data, cloud- and fog- computing, digital twins, and augmented reality will bring more value and contributions to ongoing research. Addressing other challenges (apart from scalability, security and privacy), mentioned in the paper, such as lack of regulations and standards, gas and energy consumption, interoperability, etc. should be addressed in future research.

 

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Suggestions to "Distributed ledger technology applications in food supply chains: a review of challenges and future research directions":
- The conclusions section is more of a discussion than its title indicates. In that sense, consider including the conclusions as a separate section, where you include the limitations of this research.
- Check the grammar and spelling of all work

Author Response

- The conclusions section is more of a discussion than its title indicates. In that sense, consider including the conclusions as a separate section, where you include the limitations of this research.

Thank you for the suggestion. The section was renamed to section 5. Discussion. The section 5. Discussion includes an outlook of findings related to the identified challenges and barriers, the summary of other related research, and potentials for current and future research on the topic of blockchain, DLT and IoT implementation in FSCs. A link to the summary of challenges and future research directions, elaborated in the review, is provided.

Only the major summary of contributions of the SLR, limitations of research and suggestions for future research were included in the conclusion section, the section 6. Conclusion.

- Check the grammar and spelling of all work
Thank you for the suggestion, we have proof-read the manuscript and checked the grammar and spelling of the work.