Microbial Dynamics and Quality Evolution in the Spontaneous Fermentation of the Traditional Meat Product Sjenica Sheep Stelja
, Vladimir M. Tomović 2, Sunčića Kocić-Tanackov 2, Katarina G. Marković 3, Nataša Joković 4, Ivana D. Radojević 5 and Mirjana Ž. Grujović 3,*Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis study investigated the effects of traditional production methods, regional variations, and chemical composition on the sensory quality and microbial safety of Sjenica Sheep Stelja, which may provide valuable insights for future research and food quality control. Here are some suggestions:
In Lines 35-36, it is recommended that the author arrange the keywords in alphabetical order. In the introduction section from Lines 38-103, it is suggested that the author merge some paragraphs, with each paragraph conveying a central idea. This will make the introduction more logical and engaging for readers. It should be noted that there is an extra period in Line 50.
For Figure 1 in Lines 129-130, labels should be added for the left and right images. In Lines 236-237, it is mentioned that “Sampling was carried out across three households (A, B, and V) during three distinct production seasons (1, 2, and 3)”. However, in the statistical analysis described in Lines 298-304, the author used one-way ANOVA. Has the author considered using household and season as factors to reconstruct the statistical model?
The data in Table 1 on Line 315 are listed according to household and season. It is recommended that the author add the number of replicates for each, otherwise readers may easily mistake A1, A2, and A3 for three replicates of the same group.
The elements in Figure 2 on Lines 389-390 appear very complex. It is suggested that the author divide them into 2-3 separate images to present the results more clearly. Figure 3 has a similar issue, and the author is advised to optimize the images to enhance their visual appeal. In Line 457, has the author measured the content of EPS?
What does the slash in Table 3 on Line 533 represent?
The correlation analysis on Line 543 would be more intuitive if presented in the form of a heatmap.
In Lines 598-602, it is not appropriate to have such a short paragraph as a separate Line. It should be integrated with other content, as suggested for the introduction section, to improve logic and structure instead of having many fragmented paragraphs.
In the conclusion section from Lines 701-736, it is not suitable to have so much text and so many paragraphs. The conclusion should be concise, with a maximum of two paragraphs highlighting the significance of the study and future research directions. The author is advised to streamLine this section. I would like to see a revised version.
Author Response
Comment 1: In Lines 35-36, it is recommended that the author arrange the keywords in alphabetical order. In the introduction section from Lines 38-103, it is suggested that the author merge some paragraphs, with each paragraph conveying a central idea. This will make the introduction more logical and engaging for readers. It should be noted that there is an extra period in Line 50.
Answer: Thank you for your comment. We have arranged the keywords in alphabetical order. We also rewrote the Introduction section and reorganized the text. Additionally, we deleted the extra period.
Comment 2: For Figure 1 in Lines 129-130, labels should be added for the left and right images. In Lines 236-237, it is mentioned that “Sampling was carried out across three households (A, B, and V) during three distinct production seasons (1, 2, and 3)”. However, in the statistical analysis described in Lines 298-304, the author used one-way ANOVA. Has the author considered using household and season as factors to reconstruct the statistical model?
Answer: We added the labels in Figure 1.
Regarding the statistical analysis, we acknowledge the importance of considering both household and season as factors. In our study, we initially employed a one-way ANOVA to assess overall differences. However, we used a two-way analysis of variance (ANOVA) to more accurately capture the differences in chemical characteristics between household groups (A, B, and V) and seasons (1, 2, and 3). This adjustment allows for a clearer understanding of how both factors influence the chemical parameters of bedding samples. Further, we believe that both statistical methods are important for the manuscript, as they present different approaches to analyzing the chemical characteristics. Therefore, we added the following text to the manuscript:
In material and method section:
“Additionally, a two-way analysis of variance was conducted to test the differences in chemical characteristics between households and seasons, and Tukey’s test was used for post hoc comparisons of all results.”
In Results section:
“A two-way analysis of variance (ANOVA) was conducted to examine the effects of household (A, B, V) and season (1, 2, 3) on the chemical parameters of bedding samples. The results are summarized in Supplementary Figure 1.
For pH values, no statistically significant interaction was observed between household and season, F(4, 18) = 0.85, p = 0.51. The main effect of season was also not significant, F(2, 18) = 1.82, p = 0.19. Post-hoc comparisons using Tukey’s HSD test revealed no significant differences in pH among household groups A (M = 5.45, SD = 0.14), B (M = 5.38, SD = 0.22), and V (M = 5.54, SD = 0.26), or across seasons.
For water activity (aw), there was no significant interaction effect between household and season, F(4, 18) = 1.17, p = 0.36. Similarly, the main effect of season was not statistically significant, F(2, 18) = 1.17, p = 0.33. Tukey’s test indicated no significant differences among the household groups: A (M = 0.81, SD = 0.03), B (M = 0.80, SD = 0.01), and V (M = 0.81, SD = 0.02), or among seasons.
The analysis of moisture content showed a statistically significant interaction between household and season, F(4, 18) = 5.62, p = 0.004. Significant main effects were also observed for both household, F(2, 18) = 44.50, p < 0.001, and season, F(2, 18) = 22.55, p < 0.001, with a large effect size (adjusted R² = 0.85). Post-hoc comparisons using Tukey’s test indicated significant differences in moisture content among the household groups: A (M = 45.18, SD = 1.27), B (M = 43.22, SD = 0.78), and V (M = 46.11, SD = 1.58), as well as across seasons, with the exception of season 2 (2017/18), which did not differ significantly from the others.
The analysis of total fat content revealed a highly significant interaction effect between household and season, F(4, 18) = 157.19, p < 0.001. Significant main effects were also found for household, F(2, 18) = 282.29, p < 0.001, and season, F(2, 18) = 463.88, p < 0.001, with a very large effect size (adjusted R² = 0.99). Post-hoc comparisons using Tukey’s HSD test showed significant differences in total fat content among the household groups, A (M = 8.52, SD = 1.64), B (M = 10.96, SD = 2.41), and V (M = 8.82, SD = 1.60), as well as across the different seasons.
The analysis of protein content revealed a statistically significant interaction between household and season, F(4, 18) = 9.65, p < 0.001. Both main effects were also significant: household, F(2, 18) = 5.93, p = 0.01, and season, F(2, 18) = 23.07, p < 0.001, with a large effect size (adjusted R² = 0.77). Post-hoc analysis indicated that household V (M = 34.07, SD = 1.71) differed significantly from household A (M = 35.76, SD = 1.60) and B (M = 35.45, SD = 3.22). Additionally, season 3 (2018/19) showed a significant difference compared to the other two seasons.
The analysis of salt content revealed a statistically significant interaction effect between household and season, F(4, 18) = 5.45, p = 0.005. The main effect of household approached statistical significance, F(2, 18) = 3.47, p = 0.053, while the main effect of season was not statistically significant, F(2, 18) = 2.85, p = 0.08. The effect size was moderate, with an adjusted R² of 0.50. However, post-hoc comparisons using Tukey’s HSD test indicated no significant differences between households or across seasons.
Finally, the analysis of ash content demonstrated a statistically significant interaction effect between household and season, F(4, 18) = 5.01, p = 0.007. While the main effect of household was not significant, F(2, 18) = 1.43, p = 0.265, the effect of season was significant, F(2, 18) = 7.70, p = 0.004, with a moderate effect size (adjusted R² = 0.54). Tukey’s test indicated that season 2 (2017/18) differed significantly from the other two seasons.”
In discussion section:
“The two-way ANOVA revealed that the chemical composition of bedding samples was influenced by both household and seasonal factors, although the magnitude and significance of these effects varied across parameters. While pH and water activity remained stable across households and seasons, significant interaction effects were observed for moisture, fat, protein, salt, and ash contents. Notably, total fat content exhibited the largest effect sizes and the most pronounced differences among households and seasons. Protein and moisture content were also significantly influenced by both factors, with clear sea-sonal and household-specific trends. In contrast, salt and ash contents demonstrated significant interactions, though post-hoc tests revealed limited group-level differences.”
Comment 3: The data in Table 1 on Line 315 are listed according to household and season. It is recommended that the author add the number of replicates for each, otherwise readers may easily mistake A1, A2, and A3 for three replicates of the same group.
Answer: Thank you for your comment. In Section 2.2, Sampling of Sjenica Sheep Stelja, we stated that the analyses were performed in triplicate. However, to avoid misunderstandings, we have added the following text below the table: “Mean values ± SD from triplicate measurements for each sample.”
Comment 4: The elements in Figure 2 on Lines 389-390 appear very complex. It is suggested that the author divide them into 2-3 separate images to present the results more clearly. Figure 3 has a similar issue, and the author is advised to optimize the images to enhance their visual appeal. In Line 457, has the author measured the content of EPS?
Answer: Figure 2 has now been separated into three figures (Figure 2a, 2b, and 2c). Additionally, abbreviations for each sensory attribute have been introduced to enhance the visual appeal of Figure 2. The abbreviations are as follows: EX – External appearance; HCC – Homogeneity of color at the cross-section; ICC – Intensity of the cross-sectional color; FTC – Fat tissue color; IFC – Intermuscular fat content; M – Marbling; CCC – Consistency at the cross-section; A – Aroma; CXT – Chewiness and texture; D – salivation effect (dryness); ST – Salty taste; OF – Overall flavor; ISA – Intensity of smoke aroma; R – Rancidity.
Figure 3 has been divided into six separate figures, each representing a different period, to enhance visual appeal. Figure 4 is now labeled as Figure 9.
Regarding the EPS, we did not measure its content; we only detected whether there was production. The results are presented in Supplementary Tables S1 and S2.
Comment 5: What does the slash in Table 3 on Line 533 represent?
Answer: Thank you for noticing this in our overview. We have added the information that the slash (/) indicates a species not detected.
Comment 6: The correlation analysis on Line 543 would be more intuitive if presented in the form of a heatmap.
Answer: Thank you for your suggestion. We have added a heatmap as Figure 10 in the main document and deleted the supplementary tables S4-S10 related to correlation.
Comment 7: In Lines 598-602, it is not appropriate to have such a short paragraph as a separate Line. It should be integrated with other content, as suggested for the introduction section, to improve logic and structure instead of having many fragmented paragraphs.
Answer: Thank you for your comment, we revised the Discussion section in order to improve logic and structure.
Comment 8: In the conclusion section from Lines 701-736, it is not suitable to have so much text and so many paragraphs. The conclusion should be concise, with a maximum of two paragraphs highlighting the significance of the study and future research directions. The author is advised to stream Line this section. I would like to see a revised version.
Answer: Thank you for your comment, we revised the conclusion section.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe scientific article “Microbial Dynamics and Quality Evolution in the Spontaneous Fermentation of Traditional Meat Product Sjenica Sheep Stelja” is devoted to the study of quality parameters and acceptability for consumers the traditional fermented meat product protected by a geographical indication. The peer-reviewed article presents results of physicochemical measurements, sensory evaluation, and microbiological analyses, during the 120-day ripening period of dry-cured meat product across three years and three different villages, as well as the correlation between chemical characteristics and the development of certain groups of bacteria.
The article is sound and contains interesting discussion. The authors have carefully reviewed the scientific data and results presented in publications in this field; the article provides a significant list of references. All the data experimentally obtained are clearly presented and also compared with the results of other studies. Overall, the article is highly relevant, scientifically sound, and advanced in this sector of biotechnology.
For the successful publication of this article, I recommend making minor corrections:
Firstly, the section "Materials and methods" describes many indicators and techniques, but the scheme of the overall experiment is not clearly presented. I recommend to present the overall design of the experiment
In the "Results" section: Figure 2 contains so much data that it is very difficult to recognize it. I recommend providing several separate charts for each period separately! Figure 3 is the same comment, the graphs are very difficult to understand, please divide it into several small illustrations, depending on the year of the research.
Author Response
Comment 1: Firstly, the section "Materials and methods" describes many indicators and techniques, but the scheme of the overall experiment is not clearly presented. I recommend to present the overall design of the experiment
Answer: Sorry, but I do not fully understand what you mean by this recommendation. I believe you are referring to the graphical abstract, as it is the only schematic representation of the experiments. I have created a new graphical abstract. The Materials and Methods section is written in detail, and marked with headings and subheadings, according to the instructions for authors.
Comment 2: In the "Results" section: Figure 2 contains so much data that it is very difficult to recognize it. I recommend providing several separate charts for each period separately! Figure 3 is the same comment, the graphs are very difficult to understand, please divide it into several small illustrations, depending on the year of the research.
Answer: Thank you for your comment. Figure 2 has now been separated into three figures (Figure 2a, 2b, and 2c). Additionally, abbreviations for each sensory attribute have been introduced to enhance the visual appeal of Figure 2. The abbreviations are as follows: EX – External appearance; HCC – Homogeneity of color at the cross-section; ICC – Intensity of the cross-sectional color; FTC – Fat tissue color; IFC – Intermuscular fat content; M – Marbling; CCC – Consistency at the cross-section; A – Aroma; CXT – Chewiness and texture; D – salivation effect (dryness); ST – Salty taste; OF – Overall flavor; ISA – Intensity of smoke aroma; R – Rancidity.
Figure 3 has been divided into six separate figures, each representing a different period, to enhance visual appeal. Figure 4 is now labeled as Figure 9.
