Annual Change in the Composition of Bulk Tank Milk Microbiota in Northern Kanagawa Prefecture, Japan

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript entitled “Annual change in the composition of bulk tank milk microbiota in northern Kanagawa Prefecture, Japan” edited by Reina ISHIKAWA, Kazuhiro KAWAI, Yuko SHIMIZU, Tomomi KURUMISAWA and, Yasunori SHINO ZUKA appears to be in line with the Journal and is of interest to readers.

Abstract: The conclusion in the abstract appears not clear, perhaps you should rephrase them.

Introduction: In this reviewer's opinion, the introductions are very concise and effectively introduce the topic, although some concepts are repeated. However, I would make further references to other works to better contextualize the topic at hand. overall, there has been a significant increase in the use of high throughput sequencing (HTS) methods to characterize microbial communities in milk and dairy products.

Introduction: Line 54 “The microbial control of raw milk is an important issue for the dairy industry, which is required to produce high-quality milk and dairy products” seems a repetition, see at line 35.

Introduction: line 48-50. This sentence seems too long I suggest rephrasing.

Materials and Methods: This reviewer greatly appreciates the fact that sampling is conducted every two months. It would have been interesting to evaluate different years as well. It would also be interesting to provide information regarding the feed (amount of dry matter in feed) or the type of milking (eg. automatic milking systems). Or information regarding mastitis treatments and procedures for cleaning  the milking machine.

Table 2. What do you mean "Individual"? In this context mean milk from a single farm?

Figure 3:In the Figure 3 it is indicated February for better comprehension it should be indicated also the number in parentheses (e.g., Month 2).

Discussion: How do these authors explain the presence of Listeria in the milk? It is well known that low temperature encourages the growth of psychrotrophic bacteria https://doi.org/10.1016/j.idairyj.2016.02.042.  Is it solely a matter related to temperatures? The occurrence of L. monocytogenes in bulk tank milk (BTM) has been linked to fecal contamination resulting from cows being fed contaminated or inadequately stored silage doi.org/10.1371/journal.pone.0197053.  

In general this reviewer agrees with the authors with the limitations of this study, however, he suggests that the paper be modified as best as possible for its publication. I hope these suggestions can help improve the manuscript

Author Response

We thank for your favorable comments and meaningful suggestions regarding this paper. We will answer the suggestions below on a point-by-point basis. Suggested comments are in bold, and our responses are in italics. Please see attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article is well-written and clear, but I don't think it provides enough relevant information.  In my opinion, the discussion should consider other similar studies from other parts of the world. Also, metagenomic data should be made available in appropriate databases such as NCBI. No information was given on the genera/species that could be identified in the metagenomic analysis, apart from the mention of a few species of microorganisms. In my opinion, the publication of the article deserves reservations.

 

 

Author Response

We thank for your favorable comments and meaningful suggestions regarding this paper. We will answer the suggestions below on a point-by-point basis. Suggested comments are in bold, and our responses are in italics. Please see attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

If the udder is healthy, the milk may become contaminated with germs during and after milking. Especially when hygiene measures are missing on the farm or are not taken seriously, as can be observed on many farms. Unfortunately, the authors did not mention such information in the Materials and Methods.

When were milk samples taken during the day and what was the temperature in the milk tank on the farm? 

Were the farmers asked how the hygiene measures were carried out on the individual farms? About cleaning the stable, cleaning the milking machine, cleaning the milk tank, the cleanliness of the milkers (extra clothing, infected hands or gloves used).

In Table 1, the feeding system was mentioned. This is not a feeding system, but rather a feed ration or feed mixture

Table 2 clearly shows that in 4 farms (A, C, D and E) there was a health problem with the animals as the cell count increased to over 100,000 cells/ml milk. According to current knowledge, a limit value of 100,000 cells/ml milk is used to assess the udder in order to distinguish between healthy and sick. 

Line 208 stated that cows had the same calving season on all farms, although this was not mentioned in the Materials and Methods. Was it correct or there was estrous synchronization with the animals?

The study did not provide information about the milking machine (which company) and how the animals were milked (whether the first squirts of milk were removed or not. pre-milking is necessary to flush out the teat canal, which has a high bacterial population. Whether the udder was cleaned before milking or not? How many times a day were the animals milked?

I hope that such missing information can be included in the paper so that a good scientific manuscript can be published.

Author Response

We thank for your favorable comments and meaningful suggestions regarding this paper. We will answer the suggestions below on a point-by-point basis. Suggested comments are in bold, and our responses are in italics. Please see attached file.

 

Author Response File: Author Response.pdf