Microbial Preservation and Contamination Control in the Baking Industry

Round 1

Reviewer 1 Report (New Reviewer)

Comments and Suggestions for Authors

Comments to the Authors

General remarks:

The manuscript fermentation-2933767 reviews the two significant aspects of bread-making technology: microbial resources and their preservation for safe application in bread-making and control of bread contamination during the production process as well as afterwards during transport and storage. The presented review article has interest to the scientific audience and readers, especially from the point of bread waste reduction, sustainability, and overall health of the population. Minor issues should be addressed throughout the manuscript as described below.

Abstract: Is of good quality.

Introduction: Well-written study background with a good focus on the issue in the study aim.

Page 2 – Second paragraph beginning with the sentence “The preservation techniques of microorganisms for baking or fermenting inoculum are critical and are in progressive development” font size should be uniformed with the rest of text.

Page 2 – Fourth paragraph ending with sentence “Another way to preserve is through physical and chemical methods [16].” Please specify which physical and chemical methods.

Section 3. Bread native microbiology, ingredients, and additives

Page 3 – Second paragraph beginning with the sentence “The type of flour used in making bread can have a significant impact on…” better will be to replace “making bread” with “bread-making”.

Page 4 – Third paragraph, sentence “…(a mixture of baking soda and powdered acids, all creating carbon dioxide bubbles and causing the bread to rise [42].” Please add bracket at the end.

Subsection 5.3. Spray drying

Page 8 – Sentence “The bread quality and dough network were investigated.” What is meant by dough network? Dough rheological properties or the crumb structure of the resulting bread? Please explain.

Pages 8 – 9 – Text “Highland bar-ley sourdough powder with inulin was prepared using the freeze-dried method. The bread quality and dough network were investigated. The results show that inulin was essential in preserving lactic acid bacteria and acid-producing ability com-pared to sourdough powder without inulin [73]. It was demonstrated that pure freeze-dried strain retained the aroma characteristics of Sourdough and could give bread proper acidity, improving viscoelasticity and the gluten network structure and enhancing bread quality lactic acid bacteria. S. cerevisiae XZFM15F1, L. planta-rum (L.P) 2979, L.P3355, and Lactococcus lactis were tested [74].” Consider moving to the section 5.2 Freeze drying.

Page 9 – Table 2- An overview of the survival rate of bread-making starters after freeze drying should be included in this table next to spray drying or in separate table under the subsection 5.2.

Page 11 – Sentence “…including bread ingredients and external contamination due to lack of hygiene, insects, and other factors discussed in item 4. [5,92].” Please replace “item” with section, it is more appropriate.

Page 12 – Sentence “…polymerase chain reaction (qPCR)and digital droplet polymerase chain reaction (ddPCR for the early detection and quantification of…” Please add bracket after ddPCR.

Pages 13 – 14 – Please replace the order of following sentences. “Natural preservatives, like honey, sugar, and salts (potassium, sodium, calcium), can also help extend shelf life. However, the baking industry must follow local legislation that regulates the maximum concentration of these acids in baked products [116,117].”

Page 18 – Table 5 instead of “Organisms” it will be better to be Microorganisms in the first row/second column in Table.

Conclusion: Is of good quality.

Comments for author File: Comments.docx

Author Response

Comments to the Authors

General remarks:

The manuscript fermentation-2933767 reviews the two significant aspects of bread-making technology: microbial resources and their preservation for safe application in bread-making and control of bread contamination during the production process as well as afterwards during transport and storage. The presented review article has interest to the scientific audience and readers, especially from the point of bread waste reduction, sustainability, and overall health of the population. Minor issues should be addressed throughout the manuscript as described below.

Abstract: Is of good quality.

Introduction: Well-written study background with a good focus on the issue in the study aim.

1. Page 2 – Second paragraph beginning with the sentence “The preservation techniques of microorganisms for baking or fermenting inoculum are critical and are in progressive development” font size should be uniformed with the rest of text.

 Thank you. The sentence was corrected.

2. 2. Page 2 – Fourth paragraph ending with sentence “Another way to preserve is through physical and chemical methods [16].” Please specify which physical and chemical methods.

 The text was adjusted in this paragraph according to the reviewer's comment.

Section 3. Bread native microbiology, ingredients, and additives

3.Page 3 – Second paragraph beginning with the sentence “The type of flour used in making bread can have a significant impact on…” better will be to replace “making bread” with “bread-making”.

 Making bread was replaced with bread-making

4.Page 4 – Third paragraph, sentence “…(a mixture of baking soda and powdered acids, all creating carbon dioxide bubbles and causing the bread to rise [42].” Please add bracket at the end.

The correction was done.

Subsection 5.3. Spray drying

5. 5. Page 8 – Sentence.” What is meant by dough network? Dough rheological properties or the crumb structure of the resulting bread? Please explain.

 We are specifically referring to the gluten network; the text was improved to explain this topic. The text is now in the freeze-drying subsection.

6. 6. Pages 8 – 9 – Text “Highland bar-ley sourdough powder with inulin was prepared using the freeze-dried method. The bread quality and dough network were investigated. The results show that inulin was essential in preserving lactic acid bacteria and acid-producing ability compared to sourdough powder without inulin [73]. It was demonstrated that pure freeze-dried strain retained the aroma characteristics of Sourdough and could give bread proper acidity, improving viscoelasticity and the gluten network structure and enhancing bread quality lactic acid bacteria. S. cerevisiae XZFM15F1, L. planta-rum (L.P) 2979, L.P3355, and Lactococcus lactis were tested [74].” Consider moving to the section 5.2 Freeze drying.

 The paragraph was moved for this subsection (freeze-drying section)

7.Page 9 – Table 2- An overview of the survival rate of bread-making starters after freeze drying should be included in this table next to spray drying or in separate table under the subsection 5.2.

Table 2 was created and included in the subsectionfreeze-drying.   We also included more information about the spray dryer's effect on LABS and yeasts in Table 3.

8. Page 11 – Sentence “…including bread ingredients and external contamination due to lack of hygiene, insects, and other factors discussed in item 4. [5,92].” Please replace “item” with a section, as it is more appropriate.

 The correction was done.

9. Page 12 – Sentence “…polymerase chain reaction (qPCR)and digital droplet polymerase chain reaction (ddPCR for the early detection and quantification of…” Please add bracket after ddPCR.

Done, thank you.

10.Pages 13 – 14 – Please replace the order of following sentences. “Natural preservatives, like honey, sugar, and salts (potassium, sodium, calcium), can also help extend shelf life. However, the baking industry must follow local legislation that regulates the maximum concentration of these acids in baked products [116,117].”

 The order was replaced.

11. Page 18 – Table 5 instead of “Organisms” it will be better to be Microorganisms in the first row/second column in Table.

As suggested by the reviewer, the word was replaced

Conclusion: Is of good quality.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

The review paper entitled “Microbial Preservation and Contamination Control in the Baking Industry” encompasses the most commonly used methods in bread (and food) preservation. It has been supported by a big literature database. Before the paper would be accepted for publishing, it is necessary to answer some questions:

-        Keywords – The keywords should be in the area of “review paper”, such as: bread, fermentation, microbial contamination, etc.

-        Bacillus subtilis mesentericus: no specific comment for such a usual bread contaminant.

-        Figures 1, 2, 3 – Were these figures created by the author(s)?

-        Table 5 – The table should be accommodated to fit the paper template.

-        The authors should add comments about the order of application of preservation methods, based on literature data. Should the physical method be the first one, or maybe a synergistic usage of physical, biological, chemical methods, and packaging?

-        The authors should also add comments about the most appropriate preservation method for the fermentable microorganisms for bread production, based on literature data.

-        Which methods are the most appropriate for the preservation of the environment and production facility (air, sanitation, work surface, etc.)? Or should the focus only be on bread?

Author Response

Comments and Suggestions for Authors

The review paper entitled “Microbial Preservation and Contamination Control in the Baking Industry” encompasses the most commonly used methods in bread (and food) preservation. It has been supported by a big literature database. Before the paper would be accepted for publishing, it is necessary to answer some questions:

1. Keywords – The keywords should be in the area of “review paper”, such as: bread, fermentation, microbial contamination, etc.

 The keywords were modified as the reviewer suggested.

2. Bacillus subtilis mesentericus: no specific comment for such a usual bread contaminant.

Thank you for the observation.   A  new sentence  was included in the text

3.      Figures 1, 2, 3 – Were these figures created by the author(s)?

 The figures are originals and created by one of the authors.

4.    Table 5 – The table should be accommodated to fit the paper template.

 The table was accommodated to fit the paper template.

5.    The authors should add comments about the order of application of preservation methods based on literature data. Should the physical method be the first one, or maybe a synergistic usage of physical, biological, chemical methods, and packaging?

Several factors influence the selection of methods. These include the processing facility's unique characteristics (bread chain), the production stages, and the complexity inherent in bread manufacturing, even in artisanal settings. This complexity underscores the knowledge required in this field.

 It is strongly advised against using just one method, highlighting the importance of appropriate legislation for producing bread, where the methods and essential control points must be clearly outlined. Handlers' hygiene procedures reinforce each individual's role in preventing contamination. The manipulators must have basic knowledge of the process's microbiology

. The cleaning conditions of the production premises, the origin of the water, the quality of the raw materials used, and other factors of the process can all potentially be sources of contamination. 

    Vigilance and care of these possible entry points for microorganisms are crucial when considering physical, chemical, and biological control methods. Chemical agents at an industrial level are always used to avoid bread degradation and to increase the shelf life, underscoring their significant role in bread manufacturing.

Still, there is a strong trend for using non-toxic, biodegradable agents, and there is research on developing green products for the sector.   The packaging sector is becoming increasingly innovative, and this stage is recognized as fundamental to preventing product contamination. New materials are in development. Antimicrobials and biodegradable raw materials are being applied in packaging, are important concepts for the consumer, and do not pollute the environment. The reviewer mentioned the concept of synergism, which is essential. Thermal treatment is a physical method of cereals that reduces contamination, as is electrolyzed water, but chemical and biological preservation methods accompany these procedures.  

We tried to explain all these concepts throughout the review and, as suggested by the reviewer, added some comments about this topic in the conclusion.

6. The authors should also add comments about the most appropriate preservation method for the fermentable microorganisms for bread production, based on literature data.

As suggested by the reviewer, a new text was added in section  5: Preserving and storing microbial cultures for baking.

7.    Which methods are the most appropriate for the preservation of the environment and production facility (air, sanitation, work surface, etc.)? Or should the focus only be on bread?

 As I mentioned in the answer to question number 5, no single method can guarantee complete microbiological control during bread production. However, several strategies can be implemented together, depending on the nature of the production. These strategies include air control through appropriate ventilation and refrigeration systems and water and flour quality using, for example, physical methods. It is important to maintain clean and sanitized work surfaces and hands of bread handlers and ensure they wear appropriate clothing, such as gloves and caps. Additionally, it is essential to employ chemical or biological control methods in the bread during the process.  The text was improved in section 5 and in conclusion, for  a better  understanding.

Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

Comments and Suggestions for Authors

Bread is one of the most popular and most frequently consumed food products in the world. Hence, its production technology, from obtaining raw materials to storing the finished product, is one of the current technological challenges. The presented manuscript "Microbial preservation and contamination control in the baking industry” by Vermelho et al. fits perfectly into the current topic of bakery processing.

In the manuscript, in individual chapters and subchapters, all issues are thoroughly discussed, from the fermentation process, additives and bread ingredients, forms of storing microbial cultures, and methods of controlling microbiological contamination during bread production. In my opinion, the information provided is comprehensive and does not require any supplementation.

In the presented work, reference was made to extensive literature (as many as 204 items), where approximately 60% of the cited works were published in the last five years. I believe that this is a very good result, indicating that the authors of the manuscript are familiar with the latest scientific reports on baking.

The only thing missing in the summary is a reference to future aspects of microbiological protection in the baking industry. According to the authors, this issue will be developed in the future.

I congratulate the team on a very thorough review, which will serve the scientific community (and others) for a comprehensive acquaintance with the topic of pollution control and microbiological protection in the baking industry over the next few years.

Author Response

Comments and Suggestions for Authors

Bread is one of the most popular and most frequently consumed food products in the world. Hence, its production technology, from obtaining raw materials to storing the finished product, is one of the current technological challenges. The presented manuscript "Microbial preservation and contamination control in the baking industry” by Vermelho et al. fits perfectly into the current topic of bakery processing.

In the manuscript, in individual chapters and subchapters, all issues are thoroughly discussed, from the fermentation process, additives and bread ingredients, forms of storing microbial cultures, and methods of controlling microbiological contamination during bread production. In my opinion, the information provided is comprehensive and does not require any supplementation.

In the presented work, reference was made to extensive literature (as many as 204 items), where approximately 60% of the cited works were published in the last five years. I believe that this is a very good result, indicating that the authors of the manuscript are familiar with the latest scientific reports on baking.

The only thing missing in the summary is a reference to future aspects of microbiological protection in the baking industry. According to the authors, this issue will be developed in the future.I congratulate the team on a very thorough review, which will serve the scientific community (and others) for a comprehensive acquaintance with the topic of p

1. Thank you for your comments and a new sentence was incorporated in the summary  and   new information in  the conclusion

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

The authors have incorporated the suggested corrections and significantly improved the paper. In this form, the paper is acceptable for publication.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The presented paper requires a major revision as in a current state it does not represent a coherent text but it is rather a random mixture of information, with some of them being unjustified and some lacking. In the context of microorganisms being important in baking industry (especially for prolonged shelflife and preservation) the text requires more details concerning a risk of spoilage and microorganisms involved in the process, but also characteristics of sourdough microbiota. From the other hand treating all LAB identified in sourdough as probiotics is an unjustified generalisation. In this context the chapters devoted to different methods of probiotics preservation have nothing to do with baking industry.

Comments on the Quality of English Language

Due to the necessity of major revision, the detailed comments concerning English language were not listed

Author Response

REVIEWER 1

the presented paper requires a major revision as in a current state it does not represent a coherent text but it is rather a random mixture of information, with some of them being unjustified and some lacking. In the context of microorganisms being important in baking industry (especially for prolonged shelflife and preservation) the text requires more details concerning a risk of spoilage and microorganisms involved in the process, but also characteristics of sourdough microbiota. From the other hand treating all LAB identified in sourdough as probiotics is an unjustified generalisation. In this context the chapters devoted to different methods of probiotics preservation have nothing to do with baking industry.

Point1.The presented paper requires a major revision as in a current state it does not represent a coherent text. Still, it is rather a random mixture of information, with some of them being unjustified and some lacking.

 As suggested by the reviewer, an extensive review was carried out. The text was reorganized into new topics to improve the quality and amount of the information. New figures and 1 table were done to enhance the knowledge about the theme.

Point 2. In the context of microorganisms being important in baking industry (especially for prolonged shelflife and preservation) The text requires more details concerning the risk of spoilage and microorganisms involved in the process, but also characteristics of sourdough microbiota.

The review was modified to attend to the reviewer. The part of the text about preservation and shellife has been enlarged, and new information has been added. Sourdough microbiota was included in the item 2.2

Concerning preservation methods, we focus on baking with added references but do not exclude promising methods for future use.

Point 3.    From the other hand treating all LAB identified in sourdough as probiotics is an unjustified generalisation

 We modified the text of this part.

Point 4.In this context the chapters devoted to different methods of probiotics preservation have nothing to do with baking industry.

Concerning preservation methods, we focus on methods used in baking with references (added), but we do not exclude promising methods for future use.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The review by Vermelho et al 2023 provides an overview on the preservation methods in baking, with a focus on microorganism utilization. In my opinion the main concern is that the review is too general and does not provide new perspective, limiting to a an updated list of works. The aim is not properly clear.  I suggest the Authors to narrow the field of the manuscript in order to make clearer the overall message of the works.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

REVIEWER 2

The review by Vermelho et al 2023 provides an overview on the preservation methods in baking, with a focus on microorganism utilization. In my opinion the main concern is that the review is too general and does not provide new perspective, limiting to a an updated list of works. The aim is not properly clear. I suggest the Authors to narrow the field of the manuscript in order to make clearer the overall message of the works.

Thank you. We extensively revised, adding new information, two new figures, and one table. All text was reorganized and subtopics. The review's aim is clear now, and we believe that the new information and topics made it more complete, focusing on preservation methods in baking using microorganisms and physical and chemical methods.

Author Response File: Author Response.pdf