PONE-D-21-28210Effect of Collagen Casing on the Quality Characteristics of Fermented SausagePLOS ONE

Dear Dr. Duan,

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A. M. Abd El-Aty

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Partly

Reviewer #4: Yes

Reviewer #5: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

Reviewer #4: Yes

Reviewer #5: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Plos One

PONE-D-21-28210

Effect of Collagen Casing on the Quality Characteristics of Fermented Sausage

Dear Editor,

The article deals with the effect of casing types on the quality characteristics and biogenic amine contents of the fermented sausages. The topic is interesting. It can be published in your journal after necessary corrections have been done. My specific comments and questions are below.

- What was the main purpose of this research? Why was it thought that casing type would affect the formation of biogenic amines? This idea needs to be clearly stated in the introduction section.

- Some information about biogenic amine and health issues and legal limits should be given in the introduction section.

- Line 55: what do you mean “too high”?

- Line 128: Give the incubation conditions!

- Line 131: “total number of colonies” should be “total aerobic mesophilic bacteria” throughout the manuscript.

- Line 141: Much more information about the determination of biogenic amines including the HPLC conditions should be given in the text.

- Fig 1 and Fig 1b should be given as Tables!

- Line 179-180: Please extent the sentence! It is not clear!

- Table 3: Give the total! And discuss it!

- Why the variation in pH values were important but in LAB not?

- Discussion section should be improved!

Reviewer #2: -In the manuscript PONE-D-21-28210, the authors made a comparative analysis of casing effects on sausage quality focusing on biogenic amines and selected physical characteristics. Overall, the limited contents and experiments made the manuscript very facile. Hence, the authors are recommended to evaluate the variations of other bio-molecules, particularly fats, fatty acid, and other common volatile components as well. These molecules are one of the determinants of sausage quality and hence, analyzing the effects of casing could improve the value of the manuscript. The authors should also specify the type of meat used during sausage production, and explicitly describe the HPLC protocol they have followed during the analysis/quantification of the biogenic amines. In addition, the morphology/texture of the sausage samples at each processing and storage time should be supported by optical microscope (SEM) data.

Reviewer #3: Manuscript (PlosOne)

"Effect of collagen casing on the quality characteristics of fermented sausage"

Hereby my comments to the manuscript:

I think you should add an extra keyword that included the color and texture measurements

General remark for the introduction:

Describe what casings are used now for the production of fermented sausages. You do write that there are different types of edible casings, but it would be clearer for the story if you mention that the pig casing is used as a reference, since fermented sausages are made with natural casings.

Line 55: an individual’s intake is too high? -> Do you have numbers? What is too high?

Line 64: I do not agree with the sentence that collagen casings has a similar structure to natural casing! Maybe the collagen type is similar, but how the structures and the collagen network are constructed differ quite a bit. In addition, natural intestine also contains other proteins, such as elastin, while these are not present in the collagen casings. And it is precisely the presence of these other proteins that gives the natural intestine a unique structure and texture characteristics.

Line 79: involved in this study should be replaced by investigated

Line 96: Which type/ brand/ diameter of the collagen casing did you use? Furthermore, with what equipment did you stuff the casings with meat dough? What was the filling pressure, etc? Was this kept the same for the two casing types?

Line 109: How many samples did you measure for the color analysis? What apparatus was used for shredding? Why shredding the samples for the colour analysis. Why didn’t you cut a slice of the sausage and then measure the surface colour?

Line 118: this vessel is specific for the water activity meter?

Line 123: I would at the pH of the saline solution and the concentration/ molarity of the salt solution.

Texture profile analysis: what were the settings of the texture analyser: for example speed, compression % load cell, etc. I think it is good to mention that the gumminess and chewiness of the samples are not measured, but are calculated values.

Line 167: Why is there no results description regarding the measured L, a, b values.

Line 187 – 190: Is a repetition. Already described in material and methods.

Line 213 – 214: Here you already provide an explanation for the results obtained and a conclusion while you do not do that with the other results

Line 234: Do you mean difference in permeability?

Line 240: replace which are to: as they are made

Line 241 -242: How? Are you going to make your own prefabricated collagen casing? Production of a prefabricated collagen casing is a proprietary/ specific process.

Line 243: Brandy et al. -> Brady et al. Furthermore “believed” does not sound very scientific.

Line 245 – 246: With this statement you say that PC is your reference -> is that right? Otherwise you can’t make the statement.

Line 248 – 251: what does the elasticity of the meat stuffed in PC have to do with the permeability of the casing? You are talking about elasticity of the casing, but you did not measure this?

Line 250: collagen casing is not an artificial casing -> artificial casing is a polyamide casing.

Line 251 – 253: Why? And are these small products broken down at PC?

Line 260: permeability for what? Oxygen/ water/ etc.

In general: I would rewrite the discussion part of texture. Now very confusing and not clear.

Reviewer #4: In this study, the effects of collagen casings and natural casings (pig casings) on the biogenic amine content and other quality characteristics of fermented sausage during storage were analyzed. Compared with natural casings, collagen casings could improve the quality characteristics of fermented sausage and reduce the content of biogenic amines in fermented sausage, The study is novel and the results are valuable for the choice of casings in industrial production.

But there are several problems that need to be addressed.

1. How many samples used to measure meat quality traits?

2. In the statistical analysis, “including all interactions between processing and time”, how is that present in the data?

3. There were significant differences in the same group at different periods. So, need to add some discussion about the effect of storage period on biogenic amine content and other quality characteristics of fermented sausage.

4. How collagen casings could reduce the content of biogenic amines in fermented sausage?

5. In the discussion, more theories and references are needed to support the conclusion.

Reviewer #5: The research is important in terms of knowledge about the differences between the sausages in various casings. However, the manuscript cannot be published in a current state. The Discussion is poor and is worth deeper investigation. The conclusion concerning improved texture (harder is better?) is questionable. The statement that CC influenced lower biogenic amines production should be discussed regarding increased levels of BA in PC sausages at the beginning of the fermentation, which means that casings might have contained BA and they were only transferred into the sausage. Taking into account that this is the main conclusion, the manuscript is hard to accept.

Below are my forther detailed comments:

Line 51 why is thermal stability of biogenic amines important if the fermented sausages are usually produced and eaten raw? Do you have in mind any kind of fermented sausages intended to fry/cook?

Line 73 the reference number is missing at Skaliac et al

Line 74 US-EPA PAHs should be explained

Line 75 P<0.05 P should be in italics

Line 76 It should be Zajac et al not Marzena and the number should be at the names as in like 73

Line 125 the space is missing between pH and 4.0

Line 128 The microbiological analysis should be properly described: type of diluting solution, names of microbiological media used, conditions of incubations (time/temperature)

Line 135 the type of texturometer should be mentioned

Line 138 1 cm×1 cm3 3 is missing at first cm

Line 139 the compression conditions should be included

Line 141. The type of chromatograph and detector used should be included. The methods could be described in more detail

Table 1 the significance letters should be at mean values not at errors

Line 170 The information what PC or CC stand for should be added – the table should be self-explanatory

Line 183-190 this information was already given in Materials and methods section

Line 202 There were significant differences between different capital letters in the same group at different periods (P<0.05). There were

significant differences in different lowercase letters among different groups in the

same period (P<0.05). – it should be shortened eg. Capital letters indicate….

Line 234 There were several studies in which fermented sausages produced in collagen casings were produced. Was the same low pH in CC detected? It would be worth discussing

Line 240 This comment would be adequate if the casings production would be a subject of the study. In my opinion it is not suitable here.

Line 243 It should be paraphrased. Tenderness is one of the texture parameters – there is nothing to believe in

Line 245 Why was it improved? Is harder better?

**********

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

Reviewer #4: No

Reviewer #5: No

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PONE-D-21-28210R1Effect of Collagen Casing on the Quality Characteristics of Fermented SausagePLOS ONE

Dear Dr. Duan,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Jan 15 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

A. M. Abd El-Aty

Academic Editor

PLOS ONE

AE Comments:

Still, reviewer # 3 is raising some concern over the revised form of the MS. Do go through the comments and amend the MS accordingly. Further,<o:p></o:p>

1- The P letter for statistical value should be an uppercase-italic face letter. Amend throughout the text<o:p></o:p>

2- Line 33: The results showed that with storage time increasing...amend to The results showed that with increasing the storage time, <o:p></o:p>

3- Lines 81-91:Raise a question about the novel aspect of the current study. If there were several studies (2,5, 13, 14, 15), then "what does the current MS add to the existing knowledge"? This Must be discussed and interpreted in the introduction. <o:p></o:p>

4- Full vendor details should include company, city (state) and country. Amend throughout the text<o:p></o:p>

5- Use mL, uL, L, dL throughout the MS<o:p></o:p>

6- Check spaces and punctuation throughout the MS<o:p></o:p>

7- Section: Determination of biogenic amines: You should provide the details of method performance. This should include calibration curves, linearity, LOD, LOQ, accuracy and precision of quantified biogenic amine <o:p></o:p>

8- Data in Tables should be presented as mean +/-SD, not SE<o:p></o:p>

9- Conclusion: Rewrite it again as it repeats what has been stated in the abstract<o:p></o:p>

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #3: All comments have been addressed

Reviewer #5: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #3: Partly

Reviewer #5: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #5: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #5: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #5: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Dear Editor,

The authors have revised their manuscript according to the reviewers' suggestions. Therefore, it can be accepted in its current form.

Reviewer #3: I think the sample size is too limited, especially for the texture analysis. Also the speed of measuring with TPA is rather low.

The story would have been much stronger when microscopy analysis and permeability of the casings was done.

Reviewer #5: I have only one comment regarding the indication of statistical significance. WHat I mean was that the letters should be at mean values and not at errors. e.g. 20a +/- 0.1 and not 20 +/- 0.1a . Using standard errors was correct of course.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #3: No

Reviewer #5: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PONE-D-21-28210R2

Effect of Collagen Casing on the Quality Characteristics of Fermented Sausage

PLOS ONE

Dear Dr. Duan,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

ACADEMIC EDITOR: So many files were uploaded. Upload only the last revised MS with response to the Editor's/reviewers comments. All corrections should be highlighted yellow (not in track-changes mode).

==============================

Please submit your revised manuscript by Jan 22 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

A. M. Abd El-Aty

Academic Editor

PLOS ONE

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Reviewers' comments:

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PONE-D-21-28210R3Effect of Collagen Casing on the Quality Characteristics of Fermented SausagePLOS ONE

Dear Dr. Duan,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

ACADEMIC EDITOR: The authors have to provide the additional data requested by the diligent reviewer. This will be the last option for revision. Without doing this, the MS will not considered for publication in PLOS ONE.

==============================

Please submit your revised manuscript by Jan 31 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

A. M. Abd El-Aty

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: (No Response)

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Partly

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: No

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

Reviewer #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: Although the authors improved the quality of the manuscript, they did not incorporate the additional data recommended during the past reviews and the manuscript is still superficial. The authors were advised to add data related to the variations of fats, fatty acid, and other common volatile components, but failed to do so claiming they will consider such results for another publication. Besides, results from optical microscope (SEM) analysis are still lacking. With a focus on some biogenic amines and a few physical characteristics only, the manuscript is not in the required standard to be considered for publication.

Reviewer #3: The authors have incorporated the comments. I understand that running extra texture measurements and incorporate permeability measurements is not possible. Maybe a suggestion for future articles. This article is now ready for publishing.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

Reviewer #3: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PONE-D-21-28210R4Effect of Collagen Casing on the Quality Characteristics of Fermented SausagePLOS ONE

Dear Dr. Duan,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

ACADEMIC EDITOR: Further justifications are needed as raised by the diligent reviewer. Do go through the comments and amend the MS accordingly. Proofread the text for grammar and syntax errors, if any.

==============================

Please submit your revised manuscript by Feb 19 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

A. M. Abd El-Aty

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: No

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: With the addition of data related to volatile components, the content of the manuscript has now improved to some extent. Related to this, the authors should clarify the method regarding the analysis of volatile components (lines 180-184). Specifically, the modified method, the identification procedure, and the quantification techniques along with key GC-MS parameters should be described. More importantly, it would be great if the authors incorporate the effect of storage time (21 d, 41 d and 61d) on the variations of these volatile molecules (as they did for biogenic amines).

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Effect of Collagen Casing on the Quality Characteristics of Fermented Sausage

PONE-D-21-28210R5

Dear Dr. Duan,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

A. M. Abd El-Aty

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: No

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: The authors have addressed the issues raised during the past review processes.

The manuscript is now in a good standard and can be considered for publication after rigorous language edition.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No