Correlation between Aerosol Particulates, Carcass Dirtiness, and Hygiene Indicators of Bovine Carcasses in the Abattoir Environment: Results of a Study in Italy

Round 1

Reviewer 1 Report (New Reviewer)

Goga and colleagues, present an interesting preliminary study attempting to use bioaerosol and visual monitoring of bovine carcass dirtiness as proxies of quality control in a typical abattoir. These results could provide some insights on a possible quality monitoring tool. I have the following suggestions and comments.

Title: Could be revised to interestingly read ‘‘Bioaerosol and visual monitoring of bovine carcass dirtiness as proxies of quality control: Results of a study in Italy’’. This is because the study used only one abattoir.

L23: particulate could be an example of aerosol. Do not just use the former!

L30: To me, it would be logical to report the count rather than just the presence.

In L44, your introduction should give a broader picture of food and food quality. Then explain why bovine carcass. After this, the text can conduct the reader into L44.

In Figure 1, you need to indicate the error bars. But I would think the data on microbiology and dirtiness count should not be repeated again in Table 1. In any case if tabular format is to be preferred, the Table should be brought as close as possible to the first place where it was cited.

In Figure 3, indicate the significant correlations with asterisks (*).

Figure 4, what are the R² values for these scatter plots?

Figure 5 should be presented as 4 graphs per row.

The DISCUSSION needs to be expanded based on previous studies.

In addition, discuss briefly the limitations of your study i.e., the data was from a single abattoir. Probably, a study considering a larger number of abattoirs and carcasses samples could give more insights.

There are so many redundances and repetitions in the manuscript. The manuscript needs to be proofread by a proficient English speaker.

Other suggestions are in the attached manuscript PDF file.

Comments for author File: Comments.pdf

There are evident punctuation omissions that needs to be proofread, in addition to grammatical fixes

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Please see comments in attached file.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

[Overview]

Ensuring food safety during the food manufacturing process is necessary to ensure food hygiene and protect the health of working staffs and also meet-consumers. It is hoped that a cheaper and faster method will be developed for the hygienic evaluation of the carcass production process at slaughterhouses. In this study, the authors investigated the correlation between visible contamination of carcasses and aerosol particulate microbial hygiene standards at slaughterhouses. As a result, post-slaughter microbiological testing was effective for microbial testing of carcasses, but was ineffective for evaluating microbial contamination during the slaughter process. On the other hand, aerosol monitoring in the slaughterhouse environment and visual classification of carcass soiling were considered to provide good indicators of the quality of the slaughtering process and slaughtering environment. Although this result has not significant novelty, it provides a scientific basis for the importance of environmental health in slaughterhouses, and is an important study from a public health perspective.

[Major point]

Nothing

[Minor points]

1. Line 267: Isn’t “(Figure64)” a mistake in “(Figure 6)”?

2. Table 1: What is the unit of score for each test item?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report (New Reviewer)

All my concerns on the previous version were addressed

Minor fixes required 

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

The manuscript submitted by Luca Grispoldi et al.  aims to demonstrate the possible correlation of carcass visible contamination and abattoir aerosol particulate with process hygiene criteria.  However, there are significant flaws in the experimental design.

1. The experimental design is relatively simple, especially with a small sample size, which caused low credibility of the results. 

2. The author should randomly select many  abattoissr from differen regions with inconsistent management levels to conduct relatively complex experiments in order to accurately obtain the purpose of the experiment.

3. There is no corresponding literature support for Methods of Visual dirtiness score and aerosol monitoring.

4. The detected E. coli may not be representative. During the acid excretion process of the carcass, some suitable low-temperature growth should be within the detection range.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors, I found your study very interesting and I am sure it will be an interesting publication. I have however some concerns in terms of methodology and results deriving from a confusing language associated with the stats you used. I would therefore like to read again your paper before recommending publication. See bellow details.

52 -56 Please use double quotation marks for citations, as per instructions for authors.

58 This should be EU Reg.,… as in line 54. Please check throughout including the abstract.

109 labelling (double l)

123-127 be consistent with the use of either the symbol for hour or writing in full. Check throughout. Also with the space between the figure and the unit: 44°C for 24h or 44 °C for 24 h. Check throughout.

170 It is established in the scientific community that a p-value lower than 0.05 is significant. ?????

179 check the use of singular or plural,… components,…. Were used

186 orthotran ???

189-191 careful with this sentence. While evaluating correlations there are two figures you need to look at: the p-value and the correlation value. You may have a correlation of 0.1 with a p<0.05 and also a correlation 0.7 with p>0.5. So closer to 1 is not always indicative of the existence of correlation as closer to 0 is not always indicative of inexistence.

220 I am not completely sure how you entered a logistic regression in your analysis. You need to state your dependent and independent variables. Also logistic regressions do not access correlations, instead they give probabilities and odds ratio. Please be more clear and show the parameters of your regressions.

From line 219 in your results section. Your report on the statistics used is not completely clear. I can see that this is not your area of expertise and that is fine, however, stats need to be reported accurately with a standard language, otherwise it is very difficult to follow your rationale. I would suggest this part be reviewed by a statistician or someone proficient in statistics to review the reporting style. Also, the graphs are impossible to read, so you need to increase the font size. Check if correlation is the appropriate word for the relationship or association established. Correlation is in statistics a specific type of association and the wording should be used on those occasions only. Check the stats language throughout the paper including discussion.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript titles “Correlation between aerosol particulate, carcass dirtiness, and hygiene indicators of bovine carcasses in the abattoir environment” was aimed to demonstrate the possible correlation of visible contamination of carcasses and aerosol particulate with the hygiene indicators in abattoirs. The topic is relevant and the manuscript deserves consideration. However, at current state the manuscript needs revision. The main comments and recommendations are listed below.

Abstract should be reached by the main results (data) obtained

Introduction should be expanded. More recent and relevant works should be referred in the introduction to point out the relevance of the work and to explain why the authors decided to carry out this work.  

Figure 2. The text font should be improved to make the figure readable

Table 1. The authors create a column “Escherichia coli” that shows % carcasses where E. coli was detected on the total analyzed each workday. Current presentation is not the optimal one. For example, 5.26% on the first day means 1 carcass from 19 was contaminated with E. coli. 5% on the second day means the same: 1 from 20. Is it better to change the column and to show number of contaminated carcasses? Visual dirtiness score. What is the score?  

Table 2. The same as for table 3. Additionally, dimensions of Daily particulate index and Slaughtering hours particulate index should be added.

Conclusions should be supported by the main results (data) obtained.

The text should be checked for typos and grammatical errors.

The text should be checked for typos and grammatical errors.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The author did not supplement the data with a larger sample size. I believe that a smaller sample size is fatal to the accuracy of the results, and I do not recommend the publication of this article.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

You need again to Review your stats. I cannot fully assess this paper if you don’t get these right.

For example in your paper, you write “The logistic regression showed a relationship between E. coli on the carcass and the aerobic colony count or the total coliforms ( p < 0.001) but not with the other variables (Table 3 and Figure 3).”  

But in Table 3 only the daily particle index is not significant,… all the others have p<0.05.

Also pay attention to *: P< 0.05 as you use the star in P<0.0001

Also while reporting results please include the estimated values in the table. I also assume the models have no intercept but you need to report it. You must also read the table and report the results in a common language. See for example https://www.statology.org/how-to-report-logistic-regression-results/

Your figures are also not clear. I told you before to increase the font size. Also, the p-values in Fig. 3 don’t match those in Table 3. Also, it seems (difficult to read) that you report counts on a log scale and per cm². Make sure you indicate these units in Table 3 as well.

Please check your stats throughout and as I told you before, you need someone with expertise.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors considered all comments and recommendations and decided them well. The revised manuscript can be considered for publication. 

Author Response

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Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

Dear authors,

After 2 revisons I have highlighted the need to involve a atatistician in your report as several issues were identified. I can see that a lot of things are not making sense statistically.

You told me in your reply that you added a statistician to the list of authors, however, I can see that the extra author is not a statistician as per her public profile.

I can not progress further with reviewing this article and I have to reject it.

For your consideration:

…Z-test showed a significant correlation aerobic colony count and total 283 coliforms present on each carcass (p < 0.001….

Please note the z-test is not a correlations test.

…Z-test (unpaired t-test with Fisher’s r to z) for…

z-test is one thing, independent samples t-test (not unpaired t-test) is another