Methods for Determining Polycyclic Aromatic Hydrocarbons (PAHs) in Milk: A Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

 

§  Line 9 and 11: interchange “Polycyclic aromatic hydrocarbons (PAHs)” to line 9 and use the abbreviation of “PAHs” in line 11

 

§  Lines 9 and 12: what’s the difference between milk and dairy products? If the review focused on PAHs in dairy products, then the title must be revised since the wording “dairy products” encompasses a lot. However, if the review centers on milk specifically then the title can be maintained. Kindly check and fix it accordingly.

 

§  Keywords: why “polycyclic aromatic hydrocarbons” and “PAHs” aren’t they the same? Kindly consider one.

 

§  Lines 31-35: provide reference.

 

§  Line 36: “Due to the specific interactions between them and protein in milk” what is the “them” referring to? Is it the vital micronutrients in milk or the other chemical compositions among lipids, carbohydrates aside protein? Kindly rewrite for scientific coherency.

 

§  Line 38: is cow milk the only consumable milk by humans? Aren’t there nutritional benefits for the consumption of yak, goat, camel, yak, sheep, and buffalo milk? Kindly complement the section with other animal milk consumption health benefits since the study is a review. Kindly elaborate further with other types of milk. However, in the wake of the dearth of references to other animals' milk aside from cow’s milk then it's ok. But ideally, if there are some other types kindly add them to enrich the section.

 

§  Line 65: “PAHs accumulate in the environment and enter milk through contaminated feed” Is this statement based on a referenced literature or it is a natural phenomenon associated with milk production in animals? Kindly revise the section with reference, if possible, for scientific clarity.

 

§  Line 162: define WHO for the first time.

 

§  Lines 187-190 and lines 195-200: can authors consider merging the section to avoid repetition of information since both sections present the idea of PAH production being related to the environment and mechanisms of PAH formation aren’t well unraveled? However, the first section seems to present some probable PAH formation pathways from a chemistry point of view while the latter section specifically presents PAH formation from heat treatment means of processing food. If authors want to present PAH formation under various means of processing food, then that should be well established as sub-sections for coherency. Several variables, including distance from the heat source, fuel composition used, processing conditions, cooking time, and techniques such as reuse, conching, concentration, grinding, and storage are already stated to be associated with PAH formation.

 

§  Lines 125-127 and 211-212: statements are the same. The former was even more elaborate than the latter. Also, lines 212-215 are equally presented in Table 1. Kindly consider repeating already presented ideas in various sections. Since it’s a review paper authors can go to every length to present concepts related to the subject matter. However, every section should show a different idea of finding to enrich the paper. I recommend that authors merge these sections and instead present new statements from other kinds of literature in support of the subject under review.

 

§  Line 218: “PAH4: BaP, BaA, BbF, and Chr” and line 219: “PAH8: PAH4 plus BkF, BghiP, DbahA, and IP”. Some of these abbreviations or symbols are presented in the table for correspondence whereas some aren’t in the table for correspondence. Kindly define the abbreviations which aren’t in the table and have been stated for the first time.

 

§  Line 233-264, 281, 287, 317: citations are italic [17,51] kindly make it straight as previous sections. Kindly check thoroughly and fix it where possible.

 

§  Line 224, 296, 320: presents figure descriptions above the figure why? Is that appropriate with the journal format? I recommend the figure captions be presented below the figure.

 

§  Authors have made a judicious effort in revealing an empirical review of existing literature complementing the aim of the review and I must commend that effort.

 

§  Table 2: authors should kindly define the abbreviation of QuEChERS, UHT/HTST, LLE, LMW, EPA, etc among others beneath the table for readers' coherency.

 

§  Line 518-521: check spacing.

 

§  Butter, cheese, and others are products of dairy. In this paper milk was the only specific resource considered. The authors should recheck the use of dairy products since the study didn’t consider reviewing dairy products to an extent.

 

 

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Specific points:

This review provides very useful information about PAHs in milk and milk products, viewed from several "sides". Namely, it provides an explanation of the health effects of PAHs, an overview of legal regulations and focuses especially on an overview of methods for their extraction/isolation as well as an explanation of instrumental techniques for their detection and quantification.

In order to improve the manuscript, I suggest the following corrections.

-       Key words: Keywords should complement and not repeat the title. The aim of keywords is to increase visibility of article in the databases, therefore more general words might be relevant, or words that describe the work, but are not included in the title. So, keywords need to be changed (the ones in the title should not be repeated).

L: 32-36: „ Alongside essential proteins, fats, and carbohydrates, milk contains a wealth of vital micronutrients, including calcium, magnesium, potassium, and phosphorus, as well as sodium, chloride, copper, zinc, manganese, selenium, iodine, chromium, cobalt, molybdenum, fluoride,  arsenic, nickel, silicon, and boron.” - I ask the authors to provide an appropriate reference.

 

L: 217-220: "They recommend assessing PAH contamination in food using four key hydrocarbons (PAH4: 218 BaP, BaA, BbF, and Chr) or an expanded set of eight (PAH8: PAH4 plus BkF, BghiP, 219 DbahA, and IP)." - I ask the authors to provide the full names of these compounds in addition to the abbreviations.

 Why are references in italics on page 7? For example - [17,51]. Check the same on page 8 and 9.

 L:233: “In the EU, the regulation of polycyclic aromatic hydrocarbons (PAHs) in…” - The abbreviation PAHs was already mentioned earlier, so there is no need to write the full name and abbreviation again. Therefore, you should opt for either the abbreviation or the full name in this sentence.

 L:248: “…[53,53]…” - The same reference is given twice. Please authors to check this.

Figure 3: I ask the authors to add explanations of abbreviations that are not already listed in the figure below the figure. For example, does QuEChERS mean - Quick, Easy, Cheap, Effective, Rugged and Safe?

L:368: “(AOAC 989.05).“ - In my opinion, this should be specified as a specific number of reference and all the necessary information should be given in the list of references.

Table 2 and 3. I congratulate the authors for a clear overview of the methods given in this tables.

L: 705: I ask the authors to provide complete information for reference 57 in the list of references (full name, link...)

In general:

- I believe that the authors have given an adequate/concrete introduction to the research they have presented.

- An overview of published data related to the properties of PAHs, their health aspect, their sources in food and dairy products, as well as the regulations related to them, is given in an understandable way.

- The methods that were the goal of this review are clearly stated/explained.

- I believe that the tables and figures adequately represent the explanations related to the goals set in this study.

- The conclusion is in agreement with the title of the manuscript and the objectives set in this study.

- The listed references are appropriate (please pay attention to reference number 57).

___________________

All my suggestions are for improving the manuscript. I hope all the suggestions are clear.

Best regards.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The article presents an interesting and well-detailed approach to Polycyclic Aromatic Hydrocarbons (PAHs) in milk and dairy products, but there are points that could be improved to make it more impactful and scientific. The following suggestions are provided:

1. It is suggested to remove the abbreviation of polycyclic aromatic hydrocarbons from the title.
2. It would be beneficial to include a clear section highlighting the review's objectives, summarizing the aspects the research intends to address (e.g., "evaluate analytical methods," "examine impacts on human health," etc.).
3. Some sentences are lengthy and could be more concise. For example:
   "Because milk is consumed by diverse groups, including vulnerable populations such as children and older adults, addressing the issue of PAHs in dairy products is critical"
   could be rewritten as:
   "Given its widespread consumption by vulnerable groups, including children and older adults, controlling PAHs in milk is essential."
4. Expand the discussion on the interaction between PAHs and casein micelles and lipids, addressing how this affects the effectiveness of analytical techniques.
5. Include recent studies (from the last five years) that discuss innovations in PAH analysis methods, especially those overcoming challenges in the dairy matrix.
6. Consider adding a section discussing how the results of these analyses could impact the dairy industry, particularly regarding mitigation and contamination prevention.
7. The transition between PAHs toxicity and their lipophilicity (lines 152–158) could be smoother. For instance, first explaining the physicochemical properties (non-polarity and lipophilicity) before discussing health effects would create a more logical narrative.
8. In Section 2.3, while mentioning the lack of specific limits for PAHs in milk in the EU, it could explore the impact of this regulatory gap and propose strategies for future regulations. For example, highlight how monitoring PAHs in widely consumed products like milk could enhance food safety.
9. Including more information on how PAHs are regulated in countries beyond those presented would enrich the text, providing a more comprehensive overview.
10. Methods such as SPE, SPME, and LPME are cited as promising, but specific examples of comparative studies with data or clear benefits over traditional methods are missing.
11. The concept of "green chemistry" is mentioned but lacks practical examples of how alternative methods (LPME, SPME) align with this approach. Expanding this discussion would strengthen the text’s relevance in contemporary contexts.
12. Although many studies are cited, there is little critical analysis of the methods described. A comparison between HPLC-FLD and GC-MS methods in terms of cost, sensitivity, robustness, and applicability in different matrices could be included. Additionally, discussing factors influencing the choice of a method in specific contexts, such as equipment availability and sample characteristics, would be valuable.
13. Some technical information is presented without sufficient context. The authors could briefly explain less familiar technical concepts, such as "fast-scanning fluorescence detector (FSFD)" and its specific advantages. They should also justify why certain methods, such as LC-MS, face challenges with PAH ionization, relating these issues to molecular stability.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf