Dairy Research Bulletin: Selected Articles from August 2023

Environmental Management and Sustainability

A global dataset of enteric methane mitigation experiments with lactating and non-lactating dairy cows conducted from 1963 to 2022. de Ondarza MB, Hristov AN, Tricarico JM. Data Brief. 2023;49:109459.

As both world demand for animal-sourced foods and global warming concerns rise, safe and effective strategies for enteric methane mitigation in dairy cows are in high demand. Dairy organizations worldwide announced greenhouse gas neutrality goals. Mitigation of enteric methane emissions is necessary to achieve these goals. Many innovative solutions are being tested and considered.
A dataset that compiles peer-reviewed, published research results on dietary nutrient reformulation and feed additives and their impact on both enteric methane and dairy cow performance can be used to evaluate promising options for reducing enteric methane emissions from dairy cows while maintaining dairy farm economic sustainability.
Therefore, a dataset of descriptive information was compiled from 213 peer-reviewed scientific publications that focused on dairy cow experiments and measured enteric methane emissions. For inclusion in the dataset, studies had to be written in English and provide information on enteric methane emission, as well as report feed dry matter intake along with measures of variance.
Both continuous and crossover design studies were included, resulting in a comprehensive dataset with 797 records (rows) and 162 variables (columns). The variables cover various aspects such as publication information, experimental design, animal description, methane measurement method, and diet nutrient composition. Additionally, when available, the dataset includes treatment means and measures of variance for feed dry matter intake, rumen fermentation parameters, nutrient digestibility, nitrogen excretion, milk yield, milk components, as well as enteric methane, carbon dioxide, and hydrogen emissions.
Researchers can use this dataset to assess the effectiveness of different enteric methane mitigation strategies and their impact on milk yield and other essential dairy cow nutrition and performance variables. Furthermore, it offers the opportunity to explore potential interactions between nutrients and feed additives.

Role of livestock-derived amendments in soil organic carbon stocks in forage crops. Doblas-Rodrigo Á, Gallejones P, Artetxe A, Merino P. Sci Total Environ. 2023;901:165931.

The use of organic amendments for forage production has been promoted in recent years due to the adoption of sustainable agricultural practices and the increasing cost of mineral fertilizers. Organic manures can contribute with an extra carbon to the soil to the potential addition of carbon stocks.
This study aimed to measure the capacity of different organic amendments commonly available in livestock farms for forage fertilization to influence the rate of soil organic carbon (SOC) under future climate change conditions.
For this purpose, on-farm processed exogenous organic matter (EOM) was analyzed for fiber and organic carbon mineralization to obtain the percentage of decomposable EOM and resistant EOM (DEOM and REOM, respectively). The RothC model was run in grasslands and forage maize under different scenarios considering specific DEOM and REOM values.
The results showed that the degradability of amendments could influence SOC dynamics. The SOC of grasslands after 38 years of simulation differed by >30 % between compost and the liquid fraction of cattle slurry.
Forage crops were simulated under the RCP8.5 scenario and fertilized with amendments at the recommended amounts of nitrogen for these crops. As a result, SOC stocks had a better response to organic fertilization in grassland, except under the application of the liquid fraction, with a decrease in SOC of 16 %.
In cropland, only the solid fraction from mechanical separation of slurry and compost applications increased the SOC stock from 13 % to 26 % in the 2020-2090 period.
This study provides insights into how the degradability of EOM can affect simulations of the SOC stock rate over time.

Contribution of Manure-Spreading Operations to Bioaerosols and Antibiotic Resistance Genes’ Emission. Baghdadi M, Brassard P, Duchaine C, et al. Microorganisms. 2023 Jul 13;11(7):1797.

Manure spreading from farm animals can release antibiotic-resistant bacteria (ARB) carrying antimicrobial resistance genes (ARGs) into the air, posing a potential threat to human and animal health due to the intensive use of antibiotics in the livestock industry.
This study analyzed the effect of different manure types and spreading methods on airborne bacterial emissions and antibiotic resistance genes in a controlled setting.
Cow, poultry manure, and pig slurry were spread in a confined environment using two types of spreaders (splash plate and dribble bar), and the resulting emissions were collected before, during, and after spreading using high-volume air samplers coupled to a particle counter.
Total bacteria, fecal indicators, and a total of 38 different subtypes of ARGs were further quantified by qPCR. Spreading poultry manure resulted in the highest emission rates of total bacteria (10¹¹16S gene copies/kg manure spread), Archaea (10⁶ 16S gene copies/kg manure), Enterococcus (10⁵ 16S gene copies/kg manure), and coli (10⁴ 16S gene copies/kg manure), followed by cow manure and pig slurry with splash plates and the dribble bar.
Manure spreading was associated with the highest rates of airborne aminoglycoside genes for cow and poultry (10⁶gene copies/kg manure), followed by pig slurry (10⁴ gene copies/kg manure).
This study shows that the type of manure and spreading equipment can affect the emission rates of airborne bacteria, and ARGs.

Measurement of Ammonia and Hydrogen Sulfide Emission from Three Typical Dairy Barns and Estimation of Total Ammonia Emission for the Chinese Dairy Industry. Shi Z, Xi L, Zhao X. Animals (Basel). 2023;13(14):2301.

Ammonia (NH₃) and hydrogen sulfide (H₂S) are noxious gases with characteristic odors. They are environmental contaminants and could be harmful to animals and humans. Measurement of NH₃and H₂S from dairy farms is still limited.
Therefore, there is an urgent need for accurate measurement for emissions of ammonia (NH₃) and hydrogen sulfide (H₂S) in dairy barns in order to obtain reliable emission inventories and to develop and evaluate abatement strategies.
This experiment was performed on three dairy farms in central China during 14 consecutive days in the winter 2020. Concentrations of NH₃and H₂S were measured every two hours. The samples were taken inside and outside of barns from 7 sites at two heights (at floor and 1.5 over the floor).
The results show that the average NH₃concentration was 2.47 mg/m³ with a maximum of 4.62 mg/m³, while the average H₂S concentration was 0.179 mg/m³ with a maximum of 0.246 mg/m³.
Lactating cows produced significantly more NH₃(3.73 mg/m³ versus 2.34 mg/m³) and H₂S (0.24 mg/m³ versus 0.14 mg/m³) than non-lactating cows. NH₃ and H₂S concentrations were higher at 0 m than at 1.5 m, especially during the day.
In addition, the average daily emission rates per animal unit (AU = 500 kg weight) were 23.5 g and 0.21 g for NH₃and H₂S, respectively. The emission rate for NH₃ was then used to extrapolate the NH₃ emission from the Chinese dairy production.
The estimation for 2016 was 0.45 Tg, and it could reach 1.35 Tg by 2050. These numbers reflected the first attempt to calculate emission inventories for the Chinese dairy industry. These results also suggest that more concrete measures must be taken to reduce the uncertainties of NH₃emissions from dairy cow production in China.

Water Quality and Pollution Trading: A Sustainable Solution for Future Food Production. Zapata JG, Vangipuram B, Dalin C, Erfani T. ACS ES T Eng. 2023;3(8):1112-1124.

Nitrogen, an essential nutrient for plant growth, is commonly added to food crops in the form of manure and synthetic fertilizers. Fertilizer use has significantly increased in the past decades to meet the food demands from a rising population. Although this has boosted food production, it has come at a cost to the environment.
Indeed, excess fertilizer ends up in water bodies, a pollution that causes losses in aquatic biodiversity. Better fertilizer management is therefore essential to maintaining water sustainability.
Here, researchers develop and evaluate a nitrogen water quality trading scheme to address this challenge. Nitrogen trading incentivizes farmers to work together to invest in pollution reduction measures in order to keep nitrogen water pollution levels within a standardized limit.
The researchers built a mathematical model to represent the nitrogen trading and use it to assess the pollution reduction, the effect on the crop yield, and economical outcomes. The model is applied among local farms in the agricultural county of Suffolk, eastern England. The researchers calculated the nitrogen load to the river from each farm and incorporate the abatement cost into the model.
The results show how nitrogen water pollution could be reduced cost-effectively while simultaneously increasing the benefit for the whole catchment. Although the benefit does not increase for all the farms, the increase in benefit for the whole catchment is enough to compensate for this loss. The surplus benefit is equally distributed between all the farms, thus increasing their overall benefit.
The researchers also discuss how the proposed trading model can create a platform for farmers to participate and reduce their water pollution.

Taking the diet of cows into consideration in designing payments to reduce enteric methane emissions on dairy farms. Le Gloux F, Duvaleix S, Dupraz P.J Dairy Sci. 2023:S0022-0302(23)00282-5.

Enteric fermentation from dairy cows is a major source of methane. Significantly and rapidly reducing those emissions would be a powerful lever to mitigate climate change.
For a given productivity level, introducing fodder with high sources of omega 3 content such as grass or linseed in the feed ration of dairy cows both improves the milk nutritional profile and reduces enteric methane emissions per liter.
Changing cows’ diet may represent additional costs for dairy farmers and calls for the implementation of payments for environmental services to support the transition.
This paper analyzes 2 design elements affecting the effectiveness of a payment conditioned to the reduction of enteric methane emissions: (i) the choice of emission indicator capturing the effect of farmers’ practices (ii) the payment amount relative to the extra milk production costs incurred.
Using representative farm-level economic data from the French farm accountancy data network, researchers compared enteric methane emissions per liter of milk calculated with an Intergovernmental Panel on Climate Change Tier 2 method, to baseline emissions from a Tier 3 method accounting for diet effects. They also quantified the extra milk production costs of integrating more grass in the fodder systems by estimating variable cost functions for different dairy systems in France.
The results show the relevance of using an emission indicator sensitive to diet effects, and that the significance and direction of the extra-costs for producing milk with more grass differ according to the production basin and the current share of grasslands in the fodder crop rotation.
The researchers stress the importance of developing payments for environmental services with well-defined environmental indicators accounting for the technical problem addressed, and the need to better characterize heterogeneous funding requirements for supporting a large-scale adoption of more environment-friendly practices by farmers.

Animal Health and Food Safety

The relationship between feed efficiency and behavior differs between lactating Holstein and Jersey cows. Thorup VM, Munksgaard L, Terré M, Henriksen JCS, Weisbjerg MR, Løvendahl P. J Dairy Res. 2023 Aug 24:1-4.

In dairy production, high feed efficiency (FE) is important to reduce feed costs and negative impacts of milk production on the climate and environment, yet little is known about the relationship between FE, eating behavior and activity.
This research communication describes how cows differing in FE, expressed as daily energy corrected milk production per unit of feed intake, differed in eating behavior and activity.
The researchers used data from a study of 253 lactations obtained from 97 Holstein and 91 Jersey cows milked in an automatic milking system. Automated feed troughs recorded feed intake behavior and cows wore a sensor that recorded activity from 5 to 200 d in milk (DIM). Separate analyses were performed for each breed and period.
The researchers found that individual level correlations between FE and behavior traits were stronger in Jersey than in Holstein cows. Eating rate correlated weakly negatively to FE in Holstein cows and more strongly so in Jersey cows, such that efficient Jerseys were slower eaters. The physical activity of Jersey cows was weakly and negatively correlated to FE, but this was not the case in Holstein cows.
The researchers concluded that eating rate was consistently negatively associated with FE throughout lactation for Jersey cows, but not for Holstein cows.

Research progress on the regulation of production traits by gastrointestinal microbiota in dairy cows. Liu L, Wu P, Guo A, Yang Y, Chen F, Zhang Q. Front Vet Sci. 2023 Aug 1;10:1206346.

The composition and abundance of microorganisms in the gastrointestinal tract of cows are complex and extensive, and they play a crucial role in regulating nutrient digestion, absorption, maintaining digestive tract stability, and promoting the production and health of the host.
The fermentation carried out by these microorganisms in the gastrointestinal tract is fundamental to the health and productivity of cows. Rumen microorganisms produce the majority of enzymes required to break down feed substrates, such as cellulose, protein, lipids, and other plant materials, through fermentation. This process provides energy metabolism substrates that satisfy approximately 70% of the host’s energy requirements for physiological activities.
Gut microorganisms primarily decompose cellulose that is difficult to digest in the rumen, thereby providing heat and energy to the hosts. Additionally, they have an impact on host health and productivity through their role in immune function.
Understanding the composition and function of the cow gut microbiota can help regulate dairy cattle breeding traits and improve their health status. As a result, it has become a popular research topic in dairy cattle breeding.
This article provides a review of the composition, structure, physiological characteristics, and physiological effects of the cow gut microbiota, serving as a theoretical foundation for future studies that aim to utilize the gut microbiota for dairy cattle breeding or improving production traits. It may also serve as a reference for research on gut microbiota of other ruminants.

Bacterial communities and prevalence of antibiotic resistance genes carried within house flies (Diptera: Muscidae) associated with beef and dairy cattle farms. Neupane S, Talley JL, Taylor DB, Nayduch D. J Med Entomol. 2023 Aug 23:tjad112.

House flies (Musca domestica Linnaeus) are vectors of human and animal pathogens at livestock operations. Microbial communities in flies are acquired from, and correlate with, their local environment. However, variation among microbial communities carried by flies from farms in different geographical areas is not well understood.
Therefore, researchers characterized bacterial communities of female house flies collected from beef and dairy farms in Oklahoma, Kansas, and Nebraska using 16S rDNA amplicon sequencing and PCR.
Bacterial community composition in house flies was affected by farm type and location. While the shared number of taxa between flies from beef or dairy farms was low, those taxa accounted >97% of the total bacterial community abundance.
Bacterial species richness was 4% greater in flies collected from beef than in those collected from dairy farms and varied by farm type within states. Several potential pathogenic taxa were highly prevalent, comprising a core bacterial community in house flies from cattle farms.
Prevalence of the pathogens Moraxella bovis and Moraxella bovoculi was greater in flies from beef farms relative to those collected on dairy cattle farms. House flies also carried bacteria with multiple tetracycline and florfenicol resistance genes.
This study suggests that the house flies are significant reservoirs and disseminators of microbial threats to human and cattle health.

Assessment of Stress Levels in Lactating Cattle: Analyzing Cortisol Residues in Commercial Milk Products in Relation to the Temperature-Humidity Index. Ataallahi M, Cheon SN, Park GW, Nugrahaeningtyas E, Jeon JH, Park KH. Animals (Basel). 2023 Jul 25;13(15):2407.

Chronic stress in the dairy cattle industry has negative impacts on animal health, productivity, and welfare. It has been confirmed that cortisol transfers to milk and resists the high temperature during milk processing.
This study evaluated the relationship between the milk cortisol concentration (MCC) in commercial milk products and the temperature-humidity index (THI) at the time of milk production.
Eleven commercially produced pasteurized and sterilized milk products, purchased in Chuncheon, Korea, with production dates ranging from July to October 2021 were analyzed. The MCC was extracted using diethyl ether and analyzed using an enzyme immunoassay.
The average THI values based on microclimate data provided by the Korea Meteorological Administration were 77 ± 0.8, 75 ± 1.4, 69 ± 1.4, and 58 ± 1.8, in July, August, September, and October, respectively.
The average MCC levels were 211.9 ± 95.1, 173.5 ± 63.8, 109.6 ± 53.2, and 106.7 ± 33.7 pg/mL in July, August, September, and October, respectively.
The MCC in July was higher than in August, September, and October, while it was lower in September and October than in August. Significant variations in the MCC were observed in commercial milk products across the four production months, except for two milk products.
Overall, monitoring the cortisol residue in commercial dairy milk products can be an alternative indicator of stress in dairy cattle of farms.

Effects of Cow’s Milk Processing on MicroRNA Levels. Abou El Qassim L, Martínez B, Rodríguez A, Dávalos A, López de Las Hazas MC, Menéndez Miranda M, Royo LJ. Foods. 2023 Aug 4;12(15):2950.

MicroRNAs (miRNAs) regulate gene expression and might resist adverse physicochemical conditions, which makes them potential biomarkers. They are being investigated as biomarkers of dairy production systems, based on the variations in their levels in raw milk depending on animal diet and management.
Whether miRNA levels can serve as biomarkers for dairy products remains unclear, since technological or culinary treatments, such as fermentation, may alter their levels.
Here, 10 cow dairy farms were sampled in Asturias (north-west Spain) and milk samples were subjected to microwave heating or used to produce yogurt or cheese. Total RNA was isolated from raw milk and three derived products, and levels of seven miRNAs, selected based on previous studies as possible milk production system biomarkers, were assessed by RT-qPCR.
The treatments decreased levels of all miRNAs to some extent. These results also imply that cheesemaking increases the concentration of miRNAs in this product; raw milk and cheese supposedly may provide similar concentrations of miRNAs, higher than those of yogurt and microwaved milk. They also indicate that the content of certain miRNAs in raw milk cannot necessarily be extrapolated to other dairy products.

Editorial: Microbial communities and microbiomes in dairy products. Silva CCG, Ribeiro SC, Bottari B. Front Microbiol. 2023 Aug 8;14:1265035.

Microbial communities in milk can be very complex and include numerous bacterial, yeast and fungal species originating from various sources of contamination, such as the external udder surface, milking equipment, air, water, feed, grass and soil.
Some of these microorganisms play an important role in the dairy industry, especially in fermented foods, while others can cause spoilage or compromise the safety of dairy products.
In fermented foods such as cheese, microbial communities contribute to the transformation of milk through their growth and metabolic activities. These collective genomes within microbial communities are essential for the production of many dairy products that are recognized and appreciated by consumers worldwide.
In summary, the microbial communities and microbiomes in dairy products are complex and diverse and play an important role in the production, flavor, and quality of these foods, especially PDO cheese. Microbial succession during cheese ripening is related to the ability of microbial populations to adapt to specific environmental conditions that influence the characteristics of the cheese.
The study of microbial populations using culture-independent techniques allowed a better understanding of the bacterial community and differentiation in PDO cheeses. Further research is needed to better understand the diversity of these communities and their potential impact on human health.

Human Health and Nutrition

The Relationship between Whole-Milk Dairy Foods and Metabolic Health Highlights an Opportunity for Dietary Fat Recommendations to Evolve with the State of the Science. Torres-Gonzalez, M. Nutrients. Aug 13, 2023. 15(16), 3570.

The science of dietary fats has evolved, and a body of evidence indicates they are complex bioactive nutrients that have different effects on health depending on their food source, chain length, degree of saturation, and other factors that can be affected by food processing, handling, and storage.
Dietary recommendations focused on limiting individual nutrients have not successfully reduced the incidence of obesity and chronic diseases globally. Reductionist dietary fat recommendations that consider fat only as a concentrated fuel source or ignore the complexity of fatty acids, the whole-food matrices, and the broader nutrient package from which they are derived do not represent the current state of the science on dietary fats and human health.
The aim of this opinion article is to provide a brief overview of select recent research on the effects of whole-milk dairy foods on body composition and indicators of metabolic health across the lifespan to show the gap between current knowledge and dietary guidance.
Nutrition strategies focused on single nutrient reductions are outdated, future recommendations should focus on the consumption of nutrient-rich, whole-food dietary patterns that have been demonstrated to improve cardiometabolic health. Dietary patterns that include whole foods such as fruits, vegetables, eggs, cheese, milk, meat, and fish, regardless of fat content, could improve the nutrition transition in some low- and middle-income countries by promoting overall healthy dietary patterns, and thus having a positive impact on cardiometabolic health.
As the state of the science on dietary fats and human health evolves to consider the complexity of food matrices, the total nutrient package they deliver, and the health impacts associated with dietary patterns, so too must guidelines for dietary fat.

Plasma fatty acid biomarkers of dairy consumption are associated with sex-dependent effects on metabolic syndrome components in Mexican adolescents. Trejo-Reyes R, Cantoral A, Jansen EC, et al. Ann Nutr Metab. 2023 Aug 22.

During adolescence, dairy product intake has shown conflicting associations with Metabolic Syndrome (MetS) components, which are risk factors for cardiovascular disease.
This study aims to investigate the association between plasma fatty acids (FAs) C15:0, C17:0 and t-C16:1n-7, as biomarkers of dairy intake, with MetS and its components in Mexican adolescents.
A sample of 311 participants from the ELEMENT cohort were included in this cross-sectional analysis.
The researchers found significant associations between dairy biomarkers and the median of MetS variables. In females, t-C16:1n-7 was associated with a decrease of 2.97 cm in waist circumference (Q4 vs Q1). In males, C15:0 was associated with an increase of 5.84 mm/Hg in systolic blood pressure (Q4 vs Q1). For HDL-C, researchers observed opposite associations by sex. C15:0 in males was associated with decreased HDL-C (Q3 vs Q1), while in females C15:0 and t-C16:1n-7 were associated with increased HDL-C (Q3 vs Q1) and Q4 vs Q1), respectively. Additionally, in both sexes different levels of C15:0, C17:0, and t-C16:1n-7 were associated with increased triglycerides (TG).
These results suggest that adolescent dairy intake may be associated in different directions with MetS components, and that associations are sex-dependent.

Association between milk and dairy consumption and executive functioning: A cross-sectional survey based on rural Chinese adolescents. Shi T, Fan Z, Huang B, Guan K, Zhang Z. Appetite. 2023 Aug 21:107007.

Milk and dairy product consumption continue to increase in developing countries, with positive effects on adolescent physical and mental health. However, the effect of milk and dairy product consumption on executive function of adolescents has been less reported.
This study aimed to analyze the status of milk and dairy product consumption and its association with executive function among adolescents in rural areas of China.
A three-stage stratified whole-group sampling method was used to investigate the milk and dairy product consumption status and executive function of 1360 adolescents in rural areas of China.
The proportions of adolescents in rural China with milk and dairy product consumption ≤1 time/week, 2-4 times/week, and ≥5 times/week were 39.26%, 45.07%, and 15.66%, respectively.
After adjusting for relevant confounding variables, the results showed that compared to adolescents with milk and dairy product consumption ≥5 times/week, milk and dairy product consumption 2-4 times/week (OR = 2.1) and ≤1 time/week (OR = 5.9) had a higher risk of inhibit control dysfunction.
Compared to adolescents with milk and dairy product consumption ≥5 times/week, adolescents with milk and dairy product consumption ≤1 time/week (OR = 2.1) had a higher risk of conversion the risk of flexibility dysfunction was also higher in adolescents with milk and dairy product consumption ≤1 time/week (OR = 2.1).
In conclusion, milk and dairy product consumption among adolescents in rural areas of China is inadequate and has a positive association with executive function. In the future, China should increase milk and dairy product consumption and improve executive function of adolescents in rural areas in order to promote healthy physical and mental development.

Consumption of milk and dairy products and risk of asthma in children: a systematic review and Meta-analysis. Song F, Xie Y, Guo N, Zhao H. Arch Public Health. 2023 Aug 16;81(1):147.

Some reports demonstrate that asthma benefits from milk and dairy products, however, the findings are controversial.
Therefore, researchers used meta-analysis as a tool to summarize published data on the association between dairy products consumption and asthma.
A systematic literature search was conducted to identify studies of dairy products and asthma in children. Random-effect meta-analyses with summarized data were performed for total (high/low) milk and dairy intake.
The results showed no correlation between consumption of dairy products and reduced risk of asthma (OR = 0.82). The results revealed that elevated consumption of milk and dairy has significant correlation with reduced risk of asthma in Non-Asian population (OR = 0.74) and in high quality studies (OR = 0.73). No individual study influence and publication bias was seen in the sensitivity analysis and publication bias assessment.
There was no correlation between consumption of dairy products and reduced risk of asthma. However, the researchers observed that elevated consumption of milk and dairy has significant correlation with reduced risk of asthma in Non-Asian populations and in high quality studies. More high-quality and population-specific studies should be conducted to determine the risk link between milk consumption and asthma in children.

Milk and dairy product intakes, intestinal bacteria, and respiratory infections in children of elementary school age and older in Japan. Yamakawa M, Wada K, Hayashi M, Ezaki T, Nakashima Y, Nagata C, Sumoto Y. Nutrition. 2023 Jul 1;115:112145.

Milk and dairy products contain nutrients that are beneficial for immune function and their intake is considered to be associated with reduced risk of respiratory infections, which could be modified by intestinal bacteria.
The aim of this study was to examine the associations between milk and dairy product intakes, intestinal bacteria, and respiratory infections in children of elementary school age and older in Japan.
Researchers conducted cross-sectional surveys each year from 2013 to 2015 for grades 2, 5, and 8 students of an elementary and junior high school (n = 1020). Exclusion owing to ineligibility regarding data on dietary intake, respiratory infections, and intestinal bacteria led to 922 participants for the analyses.
The odds of ≥ 4 respiratory infection episodes decreased with higher milk intake after adjusting for potential confounders, and the ORs (95% CIs) for the second and third tertile categories, compared with the first tertile category, were 0.91 and 0.48, respectively. A decreasing trend in the ORs for lactic acid drink intake was observed only in those with a low count of intestinal Faecalibacterium prausnitzii.
In conclusion, the researchers found that higher milk intake was inversely associated with respiratory infections in children older than preschool age. Higher lactic acid drink intake could be inversely associated only in children with a low prausnitzii count in the intestine.

A Comprehensive Review of Bioactive Compounds from Lactic Acid Bacteria: Potential Functions as Functional Food in Dietetics and the Food Industry. Abdul Hakim BN, Xuan NJ, Oslan SNH. Foods. 2023;12(15):2850.

Lactic acid bacteria (LAB) are beneficial microbes known for their health-promoting properties. LAB are well known for their ability to produce substantial amounts of bioactive compounds during fermentation.
Peptides, exopolysaccharides (EPS), bacteriocins, some amylase, protease, lipase enzymes, and lactic acid are the most important bioactive compounds generated by LAB activity during fermentation. Additionally, the product produced by LAB is dependent on the type of fermentation used.
LAB derived from the genera Lactobacillusand Enterococcus are the most popular probiotics at present. Consuming fermented foods has been previously connected to a number of health-promoting benefits such as antibacterial activity and immune system modulation.
Furthermore, functional food implementations lead to the application of LAB in therapeutic nutrition such as prebiotic, immunomodulatory, antioxidant, anti-tumor, blood glucose lowering actions. Understanding the characteristics of LAB in diverse sources and its potential as a functional food is crucial for therapeutic applications.
This review presents an overview of functional food knowledge regarding interactions between LAB isolated from dairy products (dairy LAB) and fermented foods, as well as the prospect of functioning LAB in human health. Finally, the health advantages of LAB bioactive compounds are emphasized.

Innovation, Economics, and Dairy Alternatives

Feedback thinking in dairy farm management: system dynamics modelling for herd dynamics. Atzori AS, Atamer Balkan B, Gallo A. Animal. 2023:100905.

Systems perspectives and system dynamics have been widely used in decision-making for agricultural problems. However, their use in dairy farm management remains limited.
This work demonstrates the use of systems approaches and feedback thinking in modelling for dairy farm management.
The application of feedback thinking was illustrated with causal loop and stock-and-flow diagrams to disentangle the complexity of the relationship among farm elements. The study aimed to identify the dynamic processes of an intensive dairy farm by mapping the animal stocks (e.g., heifers, lactating cows, dry cows) with the final objective of anticipating the expected milk deliveries over a long time period.
The project was conducted for a reference dairy farm that was intensively managed with a herd size of >2 500 cattle heads, which provided monthly farm records from Jan 2016 to Dec 2019.
Model development steps included:
- (i) problem articulation with farm interviews and data analysis;
- (ii) the development of a dynamic hypothesis and a causal loop diagram;
- (iii) the development of a stock-and-flow cattle model describing ageing chains of heifers and cows and subsequent calibration of the model parameters;
- (iv) the evaluation of the model based on lactating cows and milk deliveries against farm historical records;
- (v) the analysis of the model results.
The model characterized the farm dynamics using three main feedback loops: one balancing loop of culling and two reinforcing loops of heifers’ replacement and cows’ pregnancy, pushing milk delivery.
The model reproduced the historical oscillation patterns of lactating cows and milk deliveries with high accuracy (root mean square percentage error of 2.8 and 5.2% for the number of lactating cows and milk deliveries, respectively).
The model was shown to be valid for its purpose, and applications of this model in dairy farm management can support decision-making practices for herd composition and milk delivery targets.

Multimodal deep learning as a next challenge in nutrition research: tailoring fermented dairy products based on cytidine diphosphate-diacylglycerol synthase-mediated lipid metabolism. Wu X, Jia W. Crit Rev Food Sci Nutr. 2023 Aug 24:1-12.

Deep learning is evolving in nutritional epidemiology to address challenges including precise nutrition and data-driven disease modeling.
Fermented dairy products consumption as the implementation of specific dietary priority contributes to a lower risk of all-cause mortality, cardiovascular disease, and obesity.
Various lipid types play different roles in cardiometabolic health and fermentation process changes the lipid profile in dairy products.
Leveraging the power of multiple biological datasets can provide mechanistic insights into how proteins impact lipid pathways, and establish connections among fermentation-lipid biomarkers-protein.
The recent leap of deep learning has been performed in food category recognition, agro-food freshness detection, and food flavor prediction and regulation. The proposed multimodal deep learning method includes four steps:
- (i) Forming data matrices based on data generated from different omics layers.
- (ii) Decomposing high-dimensional omics data according to self-attention mechanism.
- (iii) Constructing View Correlation Discovery Network to learn the cross-omics correlations and integrate different omics datasets.
- (iv) Depicting a biological network for lipid metabolism-centered quantitative multi-omics data analysis.
Relying on the cytidine diphosphate-diacylglycerol synthase-mediated lipid metabolism regulates the glycerophospholipid composition of fermented dairy effectively. Innovative processing strategies including ohmic heating and pulsed electric field improve the sensory qualities and nutritional characteristics of the products.

Transforming acid whey into a resource by selective removal of lactic acid and galactose using optimized food-grade microorganisms. Zhao G, Zhao S, Hagner Nielsen L, Zhou F, Gu L, Tilahun Tadesse B, Solem C. Bioresour Technol. 2023 Aug 1;387:129594.

The presence of lactic acid and galactose makes spray drying of acid whey a significant challenge for the dairy industry.
In this study, a novel approach is explored to remove these compounds, utilizing food-grade microorganisms.
For removing lactic acid, Corynebacterium glutamicum was selected, which has an inherent ability to metabolize lactic acid but does so slowly. To accelerate lactic acid metabolism, a mutant strain G6006 was isolated through adaptive laboratory evolution, which metabolized all lactic acid from acid whey two times faster than its parent strain.
To eliminate galactose, a lactose-negative mutant of Lactococcus lactis that cannot produce lactate was generated. This strain was then co-cultured with G6006 to maximize the removal of both lactic acid and galactose.
The microbially “filtered” acid whey could readily be spray dried into a stable lactose powder. This study highlights the potential of utilizing food-grade microorganisms to process acid whey, which currently constitutes a global challenge.

Edible packaging systems for improved microbial quality of animal-derived foods and the role of emerging technologies. Bhat ZF, Bhat HF, Mohan MS, Aadil RM, Hassoun A, Aït-Kaddour A. Crit Rev Food Sci Nutr. 2023 Aug 18:1-29.

Animal-derived foods are susceptible to microbial spoilage due to their superior nutritional composition and high moisture content. Among the various options, edible packaging is a relatively nascent area and can effectively control microbial growth without substantially affecting the sensory and techno-functional properties.
Numerous studies have evaluated the effect of edible packaging systems on the microbial quality of animal-derived foods, however, a review that specifically covers the effect of edible packaging on animal foods and summarizes the findings of these studies is missing in the literature.
To fill this gap, the present review analyses the findings of the studies on animal foods published during the last five years. Studies have reported edible-packaging systems for improving microbial stability of animal foods using different biopolymers (proteins, polysaccharides, lipids, and their derivatives) and bioactive ingredients (phytochemicals, peptides, plant extracts, essential oils, and their nanoparticles, nanoemulsions or coarse emulsions).
In general, nanoparticles and nanoemulsions are more effective in controlling microbial spoilage in animal foods compared to the direct addition of bioactive agents to the film matrices.
Studies have reported the use of non-thermal and emerging technologies in combination with edible packaging systems for improved food safety or their use for enhancing functionality, bioactivity and characteristics of the packaging systems.
Future studies should focus on developing sustainable packaging systems using widely available biopolymers and bioactive ingredients and should also consider the economic feasibility at the commercial scale.

Co-fermented milk beverage has better stability and contains more health-promoting amino acid metabolites than single-strain-fermented milk beverage over one-month storage. Guo S, Sun Y, Wu T, Kwok LY, Sun Z, Wang J, Zhang H. Food Chem. 2023;430:136840.

Few studies investigated the effects of co-fermentation with bifidobacteria on post-storage changes of probiotic fermented beverages (PFBs).
Thus, this study compared the post-storage changes in physicochemical index and metabolomes of PFBs produced singly by Lacticaseibacillus paracasei PC-01 (PC-01) or in combination with Bifidobacterium adolescentis B8589 (B8589).
No significant differences were observed in the pH, titratable acidity, and viable cell counts between the two PFBs over 30-day storage. However, adding B8589 not only increased the stability of PFB (based on evaluating differences in PFBs metabolomics), but also the contents of beneficial amino acid metabolites, including 4-hydroxystyrene, gamma-aminobutyric acid, N-acetyl-l-aspartic acid, d-alanyl-d-alanine, and l-malic acid, after storage.
Overall, this study showed that B8589 is preferred to single-strain fermentation by PC-01. This study supports the concept of using bifidobacteria as starter culture in PFB production.

Quality attributes of set yogurt made from lactoperoxidase system activated cow’s milk. Assen KA, Asfaw MT, Engidasew BK. Heliyon. 2023;9(7):e17507.

Major milk constituents can be preserved by the manufacturing of products such as yoghurt to have a longer shelf-life. Yoghurt is one of the most popular fermented dairy products worldwide, with great consumer acceptance due to its basic nutrition and health benefits.
Streptococcus thermophilus and Lactobacillus bulgaricus are the two very well-known starter microorganisms causing desirable biochemical effects involved in the development of aroma, flavor, taste, texture, and increasing the sensory quality of the product.
The study aimed to assess the quality attributes of set yoghurt made from cow’s milk preserved by lactoperoxidase system (LPs).
Fresh cow’s milk was collected from Dattomilk collection center and samples were grouped to control and LPs activated. Set yoghurt was prepared immediately for the controlled samples, but in LPs activated milk, sample was kept for 9 h at 25 °C ± 2 before yoghurt was made. LP enzyme was activated within 2 h after milking by adding 1 mg/ml of sodium thiocyanate (SCN^_) and hydrogen peroxide (H₂O₂).
Totally, 36 liters of cow’s milk was used and the experiment was done in triplicates. Titratable acidity (TA) and pH were assessed every 30 min until coagulation formed. Yoghurt samples were stored for 21 days and different parameters were assessed including incubation duration, pH, TA, microbiological quality and sensory attributes.
The results revealed that LPs partially suppressed the rate of acid production during incubation of cultured milk. Yoghurt made from LPs treated milk had significantly higher pH and lower TA values. Similarly, yoghurt made from LPs treated milk had lower total bacterial counts at 24-h, 72-h and 7-days of storages. Additionally, yoghurt from LPs activated milk had lower yeast and mold counts at 24-h and 7-days.
Yoghurt made from LPs activated milk received better scores for the sensory attributes.
In general, LPs activated milk can be used for making set yoghurt without a negative effect. Further studies are needed to illustrate the LPs activated milk fitness in making other cultured milk products.

Combination of Milk and Plant Proteins to Develop Novel Food Systems: What Are the Limits? Lima Nascimento LG, Odelli D, Casanova F, et al. Foods. 2023.

In the context of a diet transition from animal protein to plant protein, both for sustainable and healthy scopes, innovative plant-based foods are being developed.
A combination with milk proteins has been proposed as a strategy to overcome the scarce functional and sensorial properties of plant proteins. Based on this mixture were designed several colloidal systems such as suspensions, gels, emulsions, and foams which can be found in many food products.
This review aims to give profound scientific insights on the challenges and opportunities of developing such binary systems which could soon open a new market category in the food industry. The recent trends in the formulation of each colloidal system, as well as their limits and advantages are here considered. Lastly, new approaches to improve the coexistence of both milk and plant proteins and how they affect the sensorial profile of food products are discussed.
Despite the advantages in the use of plant proteins for human nutrition, their pronounced taste and poor solubility limit their applicability in the food industry. To overcome this techno-functional drawback, association with animal proteins, such as milk proteins, can be an interesting strategy to increase the use of plant proteins with low compromising of food sensorial aspects.
Among the potential animal proteins that can be combined with the plant ones, milk proteins stand out due to high productions, easy isolation and purification by membrane filtration systems, stability in the dry form, tecno-functionality in dairy and non-dairy products and good acceptability for consumers.
The milk and plant proteins association can improve the sensorial and nutritional aspects of foods, increase the intake of plant proteins in processed foods, reduce costs of ingredients, decrease phase separation and/or syneresis in dairy gels. It is desired that plant proteins addition in milk-based foods can improve some properties of the system, however, this addition can alter significatively the characteristics of products, which could result in consumer rejection.
Thus, the impact of this association as well as the optimization of protein interactions must be better understood for the development of innovative products with sensory characteristics suited to the needs of consumers.