Microbiological Contamination in Different Food Service Units Associated with Food Handling

Round 1

Reviewer 1 Report

Two major criticisms can be associated with this interesting work:

• although this is a report on official inspections, the used methods should be described bit more detailed. (accessories for sampling, sample transfer to lab, cultivations or PCR analysis, selectivity for the studied organism etc)
• There is no comparison with other similar results, so it can not be evaluated, how serious these warning results are, what are the tendencies etc.

Some more comments are in the attached manuscript version indicated.

Comments for author File: Comments.pdf

Author Response

Reviewer 1 comment:

Two major criticisms can be associated with this interesting work:

- although this is a report on official inspections, the used methods should be described bit more detailed. (accessories for sampling, sample transfer to lab, cultivations or PCR analysis, selectivity for the studied organism etc)

- There is no comparison with other similar results, so it cannot be evaluated, how serious these warning results are, what are the tendencies etc.

Some more comments are in the attached manuscript version indicated.

Authors answers:

We appreciate the reviewer´s comments on our manuscript “Microbiological contamination in different food service units associated with food handling”. According to that, we have revised the original manuscript (marked up using underlined text).

Reviewer 1 comment:

Lines 23: more concrete please! pathogens, or enterobacters etc..

Line 31: that is an old thruh.

Authors answers:

Lines 23 and 31: the suggestions on abstract were marked in the revised manuscript.

Reviewer 1 comment:

2.2 - Microbiological Parameters Assessed: The measured type of microorganisms is bit confused. Would be great to a have a list (like Total mesophils, total coliforms, fecal coliforms, E. coli, S. aureus).

This is only available in Portuguese; therefore, some English version should be provided.

Authors answers:

We are in agreement with the reviewer. At “2.2 - Microbiological Parameters Assessed” part, the methods were detailed based in a Portuguese method previous described (reference 25).

This version is only available in Portuguese language and was published by the Ricardo Jorge Institute's (INSA). This institution is a National reference laboratory, developing national and international cooperation actions, whose mission is to contribute to gains in public health through research and technological development activities, health observation and epidemiological surveillance, as well as coordinating the external evaluation of laboratory quality, spreading scientific culture, foster training and education and also ensure the provision of differentiated services in these areas. Moreover, this laboratory ensures the collection, compilation and transmission of analytical data relating to the composition, including contaminants of food and feed.

Reviewer 1 comment:

Line 153: Since different microbes were considered for different sources, it would be great to see here the listing of the concrete microbe types determining the classification of food processors.

Authors answers:

The classification as “satisfactory”, “unsatisfactory” and “bad” for samples collected from kitchen utensils/crockery, as well as the classification of “satisfactory” and “unsatisfactory” for samples taken from the hands of food handlers, was clarified at “2.2 - Microbiological Parameters Assessed part”, indicating the microorganisms used in these classifications.

Reviewer 1 comment:

Let we see Canteens. 8% of the positive samples were unsatisfactory because of total coliforms, 8% because of fecal coliforms, and 8% because E. coli. All together are the 24% of positive samples. What are the other 76%? S. aureus? On the bars of Fig. 3 it also takes 10% of positive samples.

Authors answers:

At the Results part, the Figure 1 shows the proportion of positive samples taken from kitchen utensils/crockery, while Figure 3 presents the proportion of positive samples taken from hands of food handlers.

In both evaluations, we showed the percentage of positivity. For the example of canteens, when we observed 8% of total coliforms, it means that have 92% of negative results for total coliforms. The same observation should be done for the other microorganisms in different food service unities.

Reviewer 1 comment:

Comparison with other countries /earlier results is missing. Are these results outstanding of rather general in EU (at least)? What are the “unsatisfactory” and “bad” samples racio in other countries/counties? What are the know tendencies: are these numbers decreasing or increasing? Such comparisons could also clarify the significance of presented results; how risky these examined food-units are?

Authors answers:

The classification as “unsatisfactory” and “bad” is based in the adapted method (reference 25), published by the Ricardo Jorge Institute's (INSA). Thus, there are no stipulated ratings for a possible comparison.

Results of studies from other countries, which were only possible to be compared with qualitative data, were evaluated.

The evolution, with an increase or decrease in the number of cases, can only be determined by carrying out further studies, based on this classification.

The discussion and conclusion has been reviewed as suggested, and was added new paragraphs, with information about food law regulations, emphasizing new possibilities on how to minimize risks to ensure best hygienic conditions in the different food establishments.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript titled "Microbiological contamination in different food service units associated with food handling" presents the results of an official inspection in different food service units in Northeast Portugal. Food safety indicators were measured and discussed.

In general, the issue of microbial contamination during food processing belongs to the most crucial regarding food safety. That's why the data presented in the article are valuable.

The text is prepared carefully but needs a few improvements and clarification.

In the abstract, the authors write about the risk assessment. Nowadays it is defined process as a part of risk analysis. It would be good to refer to the defined risk assessment and point out the parts that the authors did. Ideally, the entire text should follow this defined process, which is described in the EU food law (Regulation 178/2002). Of course, as much as possible. 

The introduction should be supplemented with information on how the UE food law regulates this issue (Good Hygienic/Manufacturing Practice, Regulation 852/2004). Accordingly, these requirements should be addressed in the discussion of the results and conclusions.

Detailed comments

Line 40: The phrase is a generalization. Foodborne diseases most often are caused by microorganisms (viruses, bacteria, parasites) but not due to climate change and so on... The listed condition may influence the microbiota and contribute to disease development. Be precise and reformulate the sentence.

Line 143: Is the χ² test was used? If so, it should be denoted as a chi-squer test or with a Greek letter.

Line 215: Cat or cattle?

Author Response

Reviewer 2 comment:

The manuscript titled "Microbiological contamination in different food service units associated with food handling" presents the results of an official inspection in different food service units in Northeast Portugal. Food safety indicators were measured and discussed.

In general, the issue of microbial contamination during food processing belongs to the most crucial regarding food safety. That's why the data presented in the article are valuable.

The text is prepared carefully but needs a few improvements and clarification.

Authors answers:

We appreciate the reviewer´s comments on our manuscript “Microbiological contamination in different food service units associated with food handling”. According to that, we have revised the original manuscript (marked up using underlined text).

Reviewer 2 comment:

In the abstract, the authors write about the risk assessment. Nowadays it is defined process as a part of risk analysis. It would be good to refer to the defined risk assessment and point out the parts that the authors did. Ideally, the entire text should follow this defined process, which is described in the EU food law (Regulation 178/2002). Of course, as much as possible. 

Authors answers:

The manuscript has been reviewed and corrected as suggested. Because is not possible to add more sentences in the abstract due to a word limit, we add a sentence at the end of the introduction, including the Regulation 178/2002.

Reviewer 2 comment:

The introduction should be supplemented with information on how the UE food law regulates this issue (Good Hygienic/Manufacturing Practice, Regulation 852/2004). Accordingly, these requirements should be addressed in the discussion of the results and conclusions.

Authors answers:

The manuscript has been reviewed and corrected as suggested, and the Regulation 852/2004 was referenced in the introduction. In addiction we included more details about good hygienic practices in the discussion and conclusion.

Reviewer 2 comment:

Line 40: The phrase is a generalization. Foodborne diseases most often are caused by microorganisms (viruses, bacteria, parasites) but not due to climate change and so on... The listed condition may influence the microbiota and contribute to disease development. Be precise and reformulate the sentence.

Authors answers:

The manuscript was reformulated according to the reviewer's recommendations.

Reviewer 2 comment:

Line 143: Is the χ2 test was used? If so, it should be denoted as a chi-square test or with a Greek letter.

Authors answers:

The sentence was reformulated accordingly. It's chi-square test, we've added the χ2.

Reviewer 2 comment:

Line 215: Cat or cattle?

Authors answers:

It's cattle, thanks for the alert.

Author Response File: Author Response.docx

Reviewer 3 Report

In this analysis, the authors discuss the microbiological contamination in different food service units in association with food handling. The topic is interesting from a scientific point of view and partial contents of the manuscript are detailed and informative. However, there are a number of issues that require the authors’ attention before publication.

Introduction

Lines 99-100: This paragraph should be rewritten clearly stating the aims and goals of this work. At its current form it only seems like a statement.

Materials and methods

• Lines 111-112: In my opinion, all methods applied and culture media used for microbiological analysis should be referred, briefly.

Also, why did the authors not collect data about Salmonella and Listeria? Both microorganisms are well known to be present in raw meats and cause foodborne diseases.

• Lines 130-132: Regarding the hygiene status of the hands of food handlers, results were only categorized as “satisfactory” and “unsatisfactory”. Why there was  no “bad” option, as in the case of kitchen utensils/crockeries?

Results

• Lines 150-152: The location of the rest samples should also be added.
• Table 1: It has come to my attention that in some cases, samples taken are very few. For instance, samples taken from kitchen utensils/crockeries in canteens and fishmongers. As a result, samples characterized as “unsatisfactory” or “bad” are even fewer. I strongly believe those numbers are not adequate in order to obtain results with certainty. Have the authors considered the possibility of false positive results or misleading percentages? I believe this sample unsimilarity can be corrected through proper statistical interpretation. Is however the qui-square test the proper one? 

Discussion

More information and discussion is required. The authors need to compare the article’s results with the existing literature. Are those bacterial counts considered dangerous by legislation? What are the permitted counts? Are there any reported incidents of mass food poisoning due to similar hygiene conditions in other facilities? Are the contamination percentages found similar to other European countries?

Also, a paragraph with clear suggestions about worker and public awareness is needed. The authors should suggest ways to improve hygiene from simplest (e.g. the use of gloves by food handlers, disposable utensils/crockeries  etc) to more complex measures (e.g. application of ISO or EU regulations, etc).

Author Response

Reviewer 3 comment:

In this analysis, the authors discuss the microbiological contamination in different food service units in association with food handling. The topic is interesting from a scientific point of view and partial contents of the manuscript are detailed and informative. However, there are a number of issues that require the authors’ attention before publication.

Authors answers:

We appreciate the reviewer´s comments on our manuscript “Microbiological contamination in different food service units associated with food handling”. According to that, we have revised the original manuscript (marked up using underlined text).

Reviewer 3 comment:

Introduction

Lines 99-100: This paragraph should be rewritten clearly stating the aims and goals of this work. At its current form it only seems like a statement.

Authors answers:

The introduction has been reviewed and corrected as suggested. We add a sentence at the end of the introduction, explaining the aims of the study and including Portuguese and European regulations.

Reviewer 3 comment:

Materials and methods

Lines 111-112: In my opinion, all methods applied and culture media used for microbiological analysis should be referred, briefly.

Authors answers:

We are in absolute agreement with the reviewer. More information regarding methods applied and culture media used for microbiological analysis has been added at “2.2 - Microbiological Parameters Assessed” part.

Reviewer 3 comment:

Materials and methods

Also, why did the authors not collect data about Salmonella and Listeria? Both microorganisms are well known to be present in raw meats and cause foodborne diseases.

Authors answers:

We appreciate your comments. The microbial evaluation performed in this study was based in a Portuguese adapted method previous described (reference 25), which samples of hands and utensils/crockery should be follow the microbial parameters described. The microbial determinations of that samples not include Salmonella and Listeria, because our study did not include samples of food.

Reviewer 3 comment:

Materials and methods

Lines 130-132: Regarding the hygiene status of the hands of food handlers, results were only categorized as “satisfactory” and “unsatisfactory”. Why there was no “bad” option, as in the case of kitchen utensils/crockeries?

Authors answers:

In the case of kitchen utensils/crockeries the classification as “satisfactory”, “unsatisfactory” and “bad” were based on the official guidelines previously described (reference 25), while the classification as “satisfactory” and “unsatisfactory” for the hands of food handlers was only performed in this study.

The intervention of public health authorities in food establishments is different in cases of kitchen utensils/crockeries with classification as “unsatisfactory” or “bad”. In the assessment of contamination of samples collected from hands, public health authorities act when there are cases of positivity, therefore, we decided to classify in this study as "satisfactory" those in which no microorganism was present, and as "unsatisfactory" samples with at least one microorganism.

Reviewer 3 comment:

Results

Lines 150-152: The location of the rest samples should also be added.

Authors answers:

We appreciate your suggestion and the modification was carried out.

Reviewer 3 comment:

Results

Table 1: It has come to my attention that in some cases, samples taken are very few. For instance, samples taken from kitchen utensils/crockeries in canteens and fishmongers. As a result, samples characterized as “unsatisfactory” or “bad” are even fewer. I strongly believe those numbers are not adequate in order to obtain results with certainty. Have the authors considered the possibility of false positive results or misleading percentages? I believe this sample unsimilarity can be corrected through proper statistical interpretation. Is however the qui-square test the proper one?

Authors answers:

Thank you for your comment. We are aware that qui-square test has some limitations when the number of expected values are less than five in each group. However, we have several groups according to the type of food units, therefore we can’t use exact tests. In these circumstances we used the likelihood-ratio chi-square test when the expected values are less than 5. The manuscript has been reviewed and corrected as suggested.

Reviewer 3 comment:

Discussion

More information and discussion is required. The authors need to compare the article’s results with the existing literature. Are those bacterial counts considered dangerous by legislation? What are the permitted counts? Are there any reported incidents of mass food poisoning due to similar hygiene conditions in other facilities? Are the contamination percentages found similar to other European countries?

Authors answers:

The classification of samples was based in the adapted method (reference 25), published by the Ricardo Jorge Institute's (INSA), a state reference laboratory, involved in national and international cooperation actions, whose mission is health observation and epidemiological surveillance. When there are “unsatisfactory” or “bad” results, the public health authorities act with the food units involved, in order to reverse the situation and prevent possible food contamination, avoiding the occurrence of foodborne diseases.

The bibliographical review carried out, allowed us to find only qualitative studies, which associate higher levels of food contamination when utensils/hands are used in handling food in different food units. For example, Wang et al. (2020), refered that butcher shop operators that often used the same chopping board and knife to split different kinds of meat, increasing the bacterial count during this food preparation process. In addition, Kalimuddin and coowerkers (2017), refered that evisecretion and preparation of fish for sale in fishmongers can be a strong determinant of microbiological contamination of utensils used in this process. Moreover, Kotzekidou (2013), detected foodborne pathogens in sandwiches pastries and desserts partialy explained due to cross-contamination and mishandling during the food preparation.

It was not possible to find studies with quantitative results, according to the classification used in our study, in order to make the comparison that you suggest.

Reviewer 3 comment:

Discussion

Also, a paragraph with clear suggestions about worker and public awareness is needed. The authors should suggest ways to improve hygiene from simplest (e.g. the use of gloves by food handlers, disposable utensils/crockeries, etc) to more complex measures (e.g. application of ISO or EU regulations, etc).

Authors answers:

The discussion and conclusion has been reviewed as suggested, and was added new paragraphs, with information about food law regulations, emphasizing new possibilities on how to minimize risks to ensure best hygienic conditions in the different food establishments.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The manuscript titled "Microbiological contamination in different food service units associated with food handling" presents the results of an official inspection in different food service units in Northeast Portugal. Food safety indicators were measured and discussed.

The authors have made sufficient changes to the text and it can be published after the editorial and spelling correction. 

Author Response

Microbiological contamination in different food service units associated with food handling.

Reviewer 2 comment:

The manuscript titled "Microbiological contamination in different food service units associated with food handling" presents the results of an official inspection in different food service units in Northeast Portugal. Food safety indicators were measured and discussed.

The authors have made sufficient changes to the text and it can be published after the editorial and spelling correction.

Authors answers:

Thank you for your previous comments. We think they were important comments for improving our manuscript

Author Response File: Author Response.pdf

Reviewer 3 Report

Whilst it is appreciated that major comments have been mostly addressed and the manuscript has been improved, there are a few minor drawbacks that need revising before acceptance.

1.Regarding the missing Salmonella and Listeria data, I examined reference 25 and despite in portoguese, I believe there are guidelines for the microorganisms mentioned, especially Listeria. If these data are not available, I would suggest the authors to explain their experimental design, why these microorganisms were excluded e.g. because the probability or occurance of Salmonella/Listeria incidents in the facilities of interest is low or other reasons. I strongly believe it should be justified.

2.Authors:

The bibliographical review carried out, allowed us to find only qualitative studies, which associate higher levels of food contamination when utensils/hands are used in handling food in different food units. For example, Wang et al. (2020), refered that butcher shop operators that often used the same chopping board and knife to split different kinds of meat, increasing the bacterial count during this food preparation process. In addition, Kalimuddin and coowerkers (2017), refered that evisecretion and preparation of fish for sale in fishmongers can be a strong determinant of microbiological contamination of utensils used in this process. Moreover, Kotzekidou (2013), detected foodborne pathogens in sandwiches pastries and desserts partialy explained due to cross-contamination and mishandling during the food preparation.

It was not possible to find studies with quantitative results, according to the classification used in our study, in order to make the comparison that you suggest.

Answer: Very well, however the information given here could be added in the discussion section. I leave this to the authors’ judgement.

Author Response

Microbiological contamination in different food service units associated with food handling.

We appreciate the reviewer´s comments on our manuscript “Microbiological contamination in different food service units associated with food handling”. According to that, we have revised the manuscript (marked up using underlined text).

Reviewer 3 comment:

1.Regarding the missing Salmonella and Listeria data, I examined reference 25 and despite in Portuguese, I believe there are guidelines for the microorganisms mentioned, especially Listeria. If these data are not available, I would suggest the authors to explain their experimental design, why these microorganisms were excluded e.g. because the probability or occurrence of Salmonella/Listeria incidents in the facilities of interest is low or other reasons. I strongly believe it should be justified.

Authors answers:

We appreciate your comment. The survey was based on data collected for audit proposal focused on the assessment of hygiene status of hands of food handlers and surfaces and it was carried out in accordance with sanitary surveillance program at regional level. In these circumstances, microbiological analyses were performed for plate counts of coliforms, E. coli, S. aureus and mesophilic microorganisms at 30º C, as proposed by the local public health authorities. We introduced this information in the “material and methods” section – subheading “study setting and data collection”

Reviewer 3 comment

2.Authors:

The bibliographical review carried out, allowed us to find only qualitative studies, which associate higher levels of food contamination when utensils/hands are used in handling food in different food units. For example, Wang et al. (2020), refered that butcher shop operators that often used the same chopping board and knife to split different kinds of meat, increasing the bacterial count during this food preparation process. In addition, Kalimuddin and coowerkers (2017), refered that evisecretion and preparation of fish for sale in fishmongers can be a strong determinant of microbiological contamination of utensils used in this process. Moreover, Kotzekidou (2013), detected foodborne pathogens in sandwiches pastries and desserts partialy explained due to cross-contamination and mishandling during the food preparation.

It was not possible to find studies with quantitative results, according to the classification used in our study, in order to make the comparison that you suggest.

Authors answers:

The authors appreciate the reviewer´s comment.  We introduced this information in the discussion section – lines 333-342.

Author Response File: Author Response.pdf