Dairy Research Bulletin
Selected Articles from April 2026

Environmental Management and Sustainability

Climate neutral dairy in California? A study based on life cycle assessment and radiative forcing. Hereu-Morales J, Kebreab E. J Dairy Sci. 2026 Apr 9:S0022-0302(26)00340-1.

• Ruminants play a key role in achieving the global climate goal of limiting surface temperature increase to 1.5 to 2°C by 2100. In California, the dairy sector is subject to ambitious methane (CH₄) reduction targets, specifically, a 40% decrease by 2030 from 1990 levels, through strategies such as alternative manure management, anaerobic digestion and anti-methanogenic feed additives.
• These mitigation measures are intended to put California dairy on a path toward climate neutrality. However, questions remain: Are current technological improvements enough to achieve climate neutrality in dairy? What is the role of non-CH₄ greenhouse gases (GHG), such as carbon dioxide (CO₂) and nitrous oxide (N₂O), in shaping long-term climate impacts?
• This study analyses the historical climate impact of California dairy from 1950 until 2020, and forecasts different scenarios to 2030, 2050 and 2100 based on current public policies and technological development.
• The analysis integrates Life Cycle Assessment (LCA) with the recently developed Radiative Forcing Climate Footprint (RFCF), a metric that quantifies climate impact over time in terms of radiative forcing (W/m²), later translated into temperature change (°C).
• Results indicate that projected reductions in CH₄emissions drive a rapid decline in short- and middle-term climate impacts, decreasing from 1.67 mW/m² in 2020 to 1.32 mW/m² in 2050 and 0.98 mW/m² in 2100 under the lowest-emissions scenario.
• However, achieving long-term climate goals is likely to require additional reductions on CO₂and N₂O emissions. The study also identified the need for systemic changes in livestock and food production systems to achieve climate neutrality in the 21st Century.

Degradation Kinetics for Organic Nitrogen in Bioelectrochemical Systems toward Ammonia Recovery. Burns M, Wu Z, Mirsha T, Beaudet A, Mangus K, Qin M. ACS ES T Eng. 2026;6(4):1369-1381.

• Land application of dairy manure returns nitrogen (N) to the soil for crop production. However, direct land application of manure faces challenges such as nitrogen volatilization and imprecise manure nitrogen applications, which significantly contribute to losses to the environment while also reducing the nitrogen value of manure.
• Manure processing methods that can recover nitrogen, particularly organic nitrogen (orgN) in a mineralized form, in a concentrated product can increase the nutrient use efficiency, reducing the demand for manufactured nitrogen fertilizers.
• In this study, we investigate two operation configurations of bioelectrochemical systems (BES) for ammonia (NH₃) recovery from orgN in synthetic dairy manure.
• Glutamic acid, an amino acid found in high concentrations in dairy manure, was used as the N source in the synthetic feed, and the BES was operated in both microbial electrolysis cell (MEC, E = 0.8 V) and microbial fuel cell (MFC) operation modes.
• Samples from four time series experiments, two in each operation mode, were analyzed for chemical oxygen demand (COD), total nitrogen (TN), total ammoniacal nitrogen (TAN), and acetate concentrations.
• Results indicated superior N removal from the anolyte in MEC mode, with an average TN removal above 95% and first-order degradation kinetics with rate coefficients between 0.05 and 0.06 h^-1. Kinetic analysis of the Raman data revealed that glutamic acid degradation to be complex and not singularly ordered in either operation mode, requiring further quantitative study.
• This work provides vital insight into the kinetics of degradation within BES toward a more complete understanding of anode-chamber processes. Such insight can be useful in guiding further research into BES as resource recovery mechanisms and supporting BES adaptation as manure treatment processes focused on the recovery of nutrient-rich, value-added fertilizer products.

Capturing the fungal diversity in manure, lagoons, troughs, and flies at a commercial dairy. Crippen TL, Kim D, Swiger SL, Anderson RC, Arsenault RJ. Front Microbiol. 2026 Apr 13;17:1794875.

• The microbiomes within dairy facilities that could serve as reservoirs for beneficial and pathogenic fungi have not been extensively explored. Though fungi can cause food safety and animal health issues, they also represent species contributing to bovine digestion and environmental nutrient cycling.
• This study investigated whether fungal communities from specific elements at a working dairy differed between cross-vent or flow-through, free stall barn management systems and defined the possible pathogen locations.
• Shotgun metagenomics was carried out on manure, lagoons, troughs, and fly samples from the barns.
• The diversity of species was not significantly affected by management systems, except between lagoon communities. Flies carried the highest number of unique fungal species and the most abundant potential mammalian pathogens, but there was a lack of overlapping pathogen profiles between flies and the other dairy components.
• Thus, it remains unclear whether the species are being efficiently exchanged between these different components of the dairy environment, mechanically or biologically. Manure harbored the most opportunistic pathogenic species, lagoons harbored the most plant pathogens and beneficial species, and troughs had the most innocuous or understudied species.
• The results allow dairy managers to consider advantageous management systems and focus on fungal mitigation efforts at appropriate locations within the dairy.

INVITED REVIEW: Turning Dairy Food Waste into Valuable Products via Yeast Bioproduction. Gargiulo JI, Llorente B, Garcia SC, et al. J Dairy Sci. 2026 Apr 9:S0022-0302(26)00345-0.

• Dairy food waste (DFW) is a major global issue, with estimates indicating that almost 20% of production is wasted in some regions. Such losses result in economic and environmental challenges but also create opportunities to recover valuable nutrients, reduce costs, and support a more circular dairy industry.
• This review explores the sources and composition of DFW and highlights strategies to transform it into valuable bioproducts through yeast fermentation, focusing on lactose-fermenting species as near-term platforms and Saccharomyces cerevisiae as the longer-term alternative.
• Key DFW streams, particularly cheese whey and its derivatives, offer nutrient-rich substrates for bioproduction. Yeast fermentation can convert these into value-added products, such as microbial biomass, amino acids, vitamins, minerals, fatty acids, and enzymes with direct applications in dairy cattle nutrition.
• Despite this potential, challenges persist, including the inability of industrially preferred yeasts to natively metabolize lactose, the variability in DFW composition, microbial contamination, and economic, logistical, and regulatory barriers.
• Emerging approaches such as strain engineering, adaptive evolution, and biofoundry-based synthetic biology offer promising solutions. By integrating bioproduction into the dairy cycle, the industry has the potential to reduce DFW, lower greenhouse gas emissions, and create new revenue streams.

Climate change as a driver of bovine mastitis: Impacts on environmental pathogen ecology, host susceptibility, and future mitigation strategies. Leghari A, Khand FM, Laghari S, Lakho SA. Vet J. 2026 Apr 21;317:106685.

• Climate change poses an escalating threat to global dairy production by exacerbating the incidence and severity of bovine mastitis, a disease with profound economic and animal welfare implications.
• This review synthesizes emerging evidence to demonstrate that climate change acts as a multifactorial driver of mastitis risk through interconnected physiological, ecological, and epidemiological pathways.
• Elevated temperatures and humidity induce host immunosuppression via heat stress, compromising systemic and mammary-specific immune defenses. Concurrently, climatic variables alter the environmental dynamics of key pathogens (e.g., Escherichia coli, Klebsiella spp., Streptococcus uberis), enhancing their survival, proliferation, and biofilm formation.
• These changes drive extended seasonal risk windows, geographic redistribution of disease pressure, and acute spikes in incidence following extreme weather events. Furthermore, climate change intersects with antimicrobial resistance by increasing disease incidence and antibiotic use, while also promoting environmental persistence and horizontal gene transfer of resistance determinants.
• To address this compounded challenge, the review outlines a framework for climate-resilient mastitis control, integrating short-term heat abatement and housing adjustments, medium-term nutritional and genetic interventions, and long-term adaptive surveillance within a One Health approach.
• Proactive, integrated strategies are essential to mitigate the growing threat of climate-amplified mastitis and ensure the sustainability of dairy production systems. Future research must prioritize mechanistic studies, predictive modeling, and economic analyses to translate this knowledge into actionable solutions.

Public acceptance of methane-reducing feed additives as a pathway to enhancing dairy farming sustainability. Ait Sidhoum A, Stygar A, Bedoin F, Niemi J. J Dairy Sci. 2026 Apr 20:S0022-0302(26)00357-7.

• This study aims to explore public acceptance of methane-reducing feed additives in the dairy sector and to examine how information influences public acceptance of these novel feeding strategies.
• The research focuses on European citizens' responses to 3 methane-mitigating feed additives: (1) algae or seaweed extracts, (2) plant-based oils or fats, and (3) a chemical feed additive, specifically the 3-nitrooxypropanol (3-NOP). A survey of 3,220 participants from 4 EU member states (Finland, France, Poland, and Ireland) provides the data for this analysis.
• The results reveal significant differences in public acceptance, with natural additives receiving higher levels of support compared with chemical alternatives. Furthermore, the provision of additional information was found to negatively impact the acceptance of natural feed additives, while it improved support for the use of the chemical feed additive.
• Cluster analysis further revealed that these information effects were not uniform across the population. Negative reactions to additional information on algae or plant-based oils were concentrated among segments with strong animal-welfare concerns or high conscientious consumption preferences, while other groups showed little change.
• By contrast, for chemical additives, additional information increased acceptance across most attitudinal clusters. These findings suggest that public resistance to chemically-derived additives like 3-NOP may pose a barrier to their implementation.
• Information campaigns, if not carefully framed, could inadvertently reduce acceptance, highlighting the need for differentiated policy and communication strategies tailored both to the type of additive and to the specific consumer clusters most sensitive to information framing when promoting methane mitigation in the dairy sector.

Animal Health and Food Safety

Dietary tannins and compounds from fermentation of saccharomyces cerevisiae effects on intake, productive performance, enteric methane emission, and rumen microbial diversity of lactating dairy cows. Sant'ana AB, Tomich T, Silva AL et al. J Dairy Sci. 2026 Apr 20:S0022-0302(26)00358-9.

• The reduction of enteric methane emissions from ruminants is a central topic in research on sustainable livestock research. Feed additives targeting the rumen microbiome are among the strategies being explored to reduce methane emissions and improve nutrient efficiency.
• In this context, the aim of this study was to investigate the effects of an additive composed by condensed tannins and Saccharomyces cerevisiae yeast compounds on intake, productive performance, nitrogen metabolism, methane emission, and rumen microbial biodiversity of lactating Holstein and Holstein × Gyr dairy cows.
• Sixteen dairy cows (8 Holstein and 8 Holstein × Gyr) were allocated to 2 treatments following a randomized block design according to milk yield and DIM: a control treatment (CON; without additive) and an additive treatment (ADT), in which the diet contained 2.7 g/kg DM of a commercial feed additive composed of condensed tannins from Acacia mearnsii and yeast compounds derived from Saccharomyces cerevisiae (Muucare Nature®).
• The trial lasted 84 d, including a 24-d adaptation period. The animals were housed in tie stalls and kept under identical conditions. Between d 17-19 and 47-49, samples of orts and feeds offered to the animals were collected. On d 18 and 19, as well as 48 and 49, spot collections of feces and urine were performed.
• Rumen fluid was collected via an esophagus on d 22 and 52, and the microbial composition was later analyzed by 16S rRNA sequencing. The VFA concentrations and rumen ammonia nitrogen were also quantified. Methane emission was measured using the sulfur hexafluoride tracer technique.
• The additive increased the apparent digestibility of DM and OM by about 6% without affecting feed intake, milk yield, and feed efficiency. Methane emission per ECM (g/kg) was reduced by almost 30%, and methane emission per milk yield (g/kg) showed a similar trend.
• The ADT cows showed higher propionate production and a lower acetate-to-propionate ratio. The microbial diversity in the rumen was altered, with a reduced α diversity and a different community composition, including an increased abundance of Prevotella ruminicola.
• The total amount of methanogens was unchanged, although one species, Methanobrevibacter smithii, tended to be less abundant. The additive reduced methane emission and improved nutrient digestibility, rumen fermentation, and nitrogen efficiency.
• These results indicate that the additive based on Acacia tannins and Saccharomyces cerevisiae yeast is a sustainable tool to reduce methane emissions in dairy production systems without compromising milk production.

Can nutritional grouping lower feed costs and enteric methane when diets are optimized with modest ingredient changes? Gong Y, Huang CL, Cabrera VE. JDS Commun. 2026;7(3):321-326.

• Nutritional grouping (NG), where cows are fed in groups based on similar nutrient requirements, has been used as a strategy to improve the precision of nutrition delivery and thus economic returns.
• Enteric methane, one of the largest on-farm sources of greenhouse gas emissions, is strongly influenced by diet formulation. With growing concerns about climate change, it is important to evaluate whether NG can also help reduce enteric methane emissions. To address this, we developed an open-source linear optimization model to assess the impact of NG on both feed cost and enteric methane emissions.
• Therefore, researchers conducted a case study with 675 cows from the University of Wisconsin's Arlington Agricultural Research Station. Diets were formulated using the farm's actual feed ingredients and prices and were constrained according to current dairy cattle feeding guidelines.
• Without NG, optimization alone reduced feed cost by $2.52/cow per day (32%) under the cost-minimization objective, and reduced methane emissions by 57 g/cow per day (12%) under the methane-minimization objective, relative to the on-farm diet used during the study period.
• Under a dual-objective approach that simultaneously considered feed cost and enteric methane emissions, the model identified a pragmatic compromise solution. By placing greater emphasis on economic performance to reflect the current US production context, methane emissions decreased by 55 g/cow per day compared with the cost-minimization scenario while maintaining similarly low feed costs.
• Nutritional grouping did not consistently outperform the optimized single-group diet, but it modestly improved the nontarget outcome (lower methane when minimizing cost and lower cost when minimizing methane).
• These findings indicate that well-optimized rations using existing feeds can deliver meaningful economic and environmental benefits, and NG offers an additional layer of management refinement that may not only reduce the feed cost as suggested by literature, but also offer complementary benefits when methane is considered as a secondary performance dimension.

A systematic review and meta-analysis of the effects of inclusion of microalgae in dairy cows' diets on nutrient digestibility, fermentation parameters, blood metabolites, milk production, and fatty acid profiles. Boukrouh S, Karouach F, Hirich A, et al. Arch Anim Breed. 2026 Feb 10;69(1):101-115.

• Recently, microalgae have been used as protein supplements to improve the productivity of dairy cows. However, the results are inconsistent among different studies.
• Thus, the aim of this study was to assess the effects of dietary microalgae incorporation on animal performance.
• The effect of microalgae was assessed by examining the raw mean differences (RMDs) between the treatment (with microalgae) and control (without microalgae) diets using a random-effect model.
• Microalgae supplementation decreased the intake of dry matter (DM), organic matter, and neutral detergent fiber (NDF). NDF digestibility improved, whereas the acetate : propionate ratio decreased.
• Milk and lactose yields remained unchanged.
• Despite a decrease in milk fat, the fatty acid (FA) profile improved, especially considering the increase in conjugated linoleic acid (CLA) C18:2 c9t11, docosahexaenoic acid (DHA) C22:6 n-3, and mono- and polyunsaturated FA (MUFA and PUFA) and the decrease in the n-6 : n-3 ratio.
• The main sources of variation in the responses to microalgal inclusion in cow milk production and quality were the animal breed, microalgae species, and their level of incorporation.
• In general, the incorporation of 61-100 g kg DM^-1of microalgae improved milk beneficial FA, including eicosapentaenoic acid (EPA) C20:5 n-3 and DHA, and Schizochytrium increased DHA levels.
• The Holstein and Friesian breeds were characterized by a significant decrease in saturated FA (SFA). As a result, microalgae supplementation could be a sustainable agricultural practice for improving dairy cow milk quality.

Integrated metatranscriptomics identifies Lachnospiraceae as keystone taxa regulating rumen biohydrogenation and milk omega-6/omega-3 polyunsaturated fatty acids ratio in dairy cows. Zhang H, Mao W, Mao S, et al. Microbiome. 2026 Apr 13.

• Enhancing milk nutritional quality through increased ω-3 polyunsaturated fatty acid (PUFA) content and a reduced ω-6/ω-3 PUFA ratio represents a significant opportunity for improving dairy products.
• While ruminal biohydrogenation substantially influences milk fatty acid (FA) composition, the specific microbial mechanisms regulating the milk fat ω-6/ω-3 PUFA ratio remain poorly characterized.
• This study aimed to identify key microbial taxa and metabolic pathways controlling this nutritionally relevant parameter, thereby establishing a foundation for targeted microbiome interventions to optimize milk FA profiles.
• Analysis of 95 Holstein cows revealed that rumen bacterial community composition explained 41.0% of the variation in the milk ω-6/ω-3 PUFA ratio. Comparative analysis of cows with contrasting phenotypes (high-ratio, HFR; low-ratio, LFR) demonstrated distinct FA profiles across rumen fluid, serum, and milk, with α-linolenic acid (ALA, C18:3 C9,12,15) and linoleic acid (LA, C18:2 C9,12) emerging as critical determinants.
• Integrated metatranscriptomic and amplicon sequencing identified members of the family Lachnospiraceae, particularly Butyrivibrio and Eubacterium genera, as central regulators of PUFA metabolism.
• Collectively, these results indicate that rumen microbial community structure and transcriptional activity are closely associated with variation in the milk ω-6/ω-3 PUFA ratio. Members of Lachnospiraceae appear to contribute to substrate-specific biohydrogenation processes that may influence downstream milk FA composition.
• These findings provide a multi-omics framework for understanding microbiome-lipid interactions and support future efforts to develop microbiome-targeted strategies for improving dairy nutritional quality.

Trends in Veterinary Drug Residues in US Cattle: Analyzing USDA Sampling Data. Alwahaimed AS, Eifert J. Vet Med Sci. 2026;12(3):e70941.

• Cattle production is the leading agricultural industry in the United States, accounting for the largest portion of total cash receipts for agricultural commodities. The administration of veterinary drugs in food-producing animals can lead to the presence of drug residues in food products.
• The primary purpose of this study is to evaluate US national residue monitoring data to identify the most frequently detected veterinary drugs across various cattle types including dairy cows, beef cows, calves, heifers, and other types. Veterinary drug residue sampling reports and datasets for the years 2021, 2022, and 2023 were evaluated using descriptive statistical analysis to rank the most frequently detected drug residues in cattle.
• A total of 3391 positive veterinary drug residue samples (including both violative and non-violative residues) were detected across all food animal species for the years 2021, 2022, and 2023 with cattle samples having the majority of positive detections (3107 samples; 92%).
• Across all three years, dairy cows accounted for the highest number of residue detections (1264), including both violative and non-violative detections, compared with other cattle types, beef cows (505), bob veal (449), steers (384), and heifers (263).
• A Pearson's Chi-squared test indicated that the distribution of residue detections varied among cattle types (p < 0.0001).
• Among the violative residues, desfuroylceftiofur was the most frequently detected analyte (351 detections), followed by penicillin (161), flunixin (122), sulfadimethoxine (94), and sulfamethazine (79).
• In conclusion, this study highlights consistent patterns in veterinary drug residue detections in cattle from 2021 to 2023 revealing major issues in residue control and compliance. These findings underscore the importance of addressing the persistent presence of certain veterinary drugs in cattle products, support the continued role of targeted residue monitoring programs, and inform future evaluations of drug use and surveillance priorities.

Whole Genome Sequencing Reveals Genetic Variability of Escherichia coli Across Dairy Farm Environments. Veloo Y, Rajendiran S, Rahman SA, Zakaria Z, Thahir SSA. Antibiotics (Basel). 2026;27;15(4):344.

• Antimicrobial agents have revolutionized disease management in humans and animals; however, their misuse and overuse have accelerated the emergence and spread of antimicrobial resistance (AMR) and antimicrobial resistance genes (ARGs).
• Dairy farms are recognized as potential hotspots for ARG dissemination, particularly through Escherichia coli, which acts as a reservoir and vector of ARGs, enabling their horizontal transfer via plasmids and other mobile genetic elements.
• This study aimed to characterize the genomic diversity, ARG profiles, plasmid content, and phylogenetic relationships of  coliisolated from dairy farm environments and milk using whole-genome sequencing.
• A total of 31  coliisolates recovered from soil, effluent, cow dung, and milk samples underwent deoxyribonucleic acid extraction, library preparation, and sequencing on the Illumina MiSeq platform, followed by comprehensive bioinformatic analysis. Results: The E. coli isolates exhibited 20 distinct sequence types, including one novel sequence type.
• Plasmids were detected in 71% of the isolates, with the IncF plasmid family being the most predominant. Furthermore, 12 ARG groups were identified, with β-lactam resistance genes detected in 67.7% of isolates. Notably, blaCTX-M genes were identified in all phenotypically confirmed extended-spectrum β-lactamase-producing isolates.
• Additional ARGs, including those conferring resistance to tetracyclines (tet(A), tetX4), quinolones (qnrS1), aminoglycosides (aph, aad, ant), and folate pathway inhibitors (dfrand sul), were widely distributed throughout the samples.
• Phylogenetic analysis revealed clustering of isolates from different sample types, particularly among ST58 isolates, suggesting cross-environmental transmission.
• In conclusions, this study demonstrates that  colifrom dairy farm environments harbor diverse ARGs and plasmids, confirming their role as reservoirs of AMR. These findings underscore the importance of prudent antimicrobial use, routine genomic surveillance, and enhanced biosecurity measures to limit cross-environmental transmission.

Nutrition and Health

 

A narrative review of nutritional components, health effects, and disease prevention mechanisms of dairy products. Wang M, Wang Q, Chen B, Liu J. Front Public Health. 2026 Apr 8;14:1799734.

• As an integral component of the human diet, dairy products are rich in high-quality protein, lactoferrin, conjugated linoleic acid, calcium, vitamin D, and various other nutrients and bioactive compounds. They exert broad health benefits through core mechanisms involving multiple pathways and targets.
• This article systematically reviews the nutritional composition of dairy products, provides an in-depth analysis of their fundamental mechanisms-such as gut-immune axis regulation and antioxidant-anti-inflammatory synergy-and comprehensively summarizes their preventive value in metabolic-related diseases, bone health, degenerative diseases, and malignancies.
• The interplay and synergistic effects among multiple components and mechanisms are discussed, along with future research directions, to offer a scientific basis for the application of dairy products in public health and clinical nutrition.

Fermented Dairy Food Intake and Risk of Depression and Dementia in Later Life: Findings from a Prospective Cohort of Older Australians. Idrus M, Bliuc D, Dai Z, et al. Nutrients. 2026 Mar 24;18(7):1020.

• Fermented dairy foods, such as yogurt and cheese, contain bioactive components that differ from those in non-dairy foods, but their associations with depression and dementia risk in later life remain unclear.
• Therefore, researchers analyzed data from the Sydney Memory and Ageing Study, a community-dwelling cohort of adults aged 70-90 years, to examine associations between dairy intake and depressive symptoms (Geriatric Depression Scale-15), psychological distress (Kessler-10), and incident depression (physician diagnosis or antidepressant use) and dementia (DSM-IV criteria).
• Intake of yogurt, cheese, and non-fermented milk was assessed at baseline using a validated food-frequency questionnaire. Longitudinal associations were examined using Fine-Gray competing-risks models that accounted for death; cross-sectional associations were also assessed.
• Among 966 participants (mean age: 78.3; 55.5% women), compared with no consumption, higher yogurt intake (one standard serving) was significantly associated with lower depressive symptom scores (adjusted β: -0.37 and -0.39 for quartiles 3-4 (mean: 88.5-164 g/day), and so was low-fat cheese intake (mean: 13.2 g/day) (adjusted β: -0.35).
• Over a mean follow-up of 3.3 years, 120 incident cases of depression and 68 deaths occurred: higher yogurt intake and low-fat cheese consumption (versus non-consumption) were associated with lower risk of depression (adjusted subdistribution hazard ratios 0.41 and 0.40, respectively).
• No significant associations were observed for psychological distress, cognition, or incident dementia (a mean follow-up of 5.2 years, 100 incident cases, and 153 deaths); no associations were observed for regular cheese or milk intake.
• These findings suggest a potential role for fermented dairy foods, particularly yogurt and low-fat cheese intake, but not non-fermented milk, in mental well-being in later life.

Exploring the dairy milk matrix beyond isolated nutrients-a narrative review. O'Sullivan TA, Nicholl A. Crit Rev Food Sci Nutr. 2026 Apr 15:1-21.

• The concept of the food matrix considers individual components along with how they are structured, interact, and are modified during processing. There is increasing interest around the health effects of individual nutrients versus whole foods, creating a need to better understand how the matrix may influence health outcomes.
• This narrative review explores the dairy milk matrix and compares health effects with those of isolated components, with additional comparisons to plant-based milk alternatives.
• Comparative evidence suggests that while calcium from food and supplements generally has similar effects (depending on the form of the supplemental calcium), consumption of food-based sources such as milk may have fewer adverse effects associated with high-dose supplemental intake.
• Fermented milk products appear to offer additional health benefits compared with unfermented milk, likely due to bioactive compounds produced during fermentation.
• Structural and functional manipulation of milk proteins, such as whey and lactoferrin, can also modify matrix functionality; for example, appropriate processing conditions can preserve lactoferrin's iron-binding capacity, supporting iron transport and bioavailability.
• Compared with plant-based milks, which often require fortification and extensive processing, the dairy milk matrix is particularly effective at promoting nutrient absorption. These findings highlight the importance of adopting a whole food perspective when considering milk in dietary recommendations and research.

Causal relationship between dairy intake and obesity: a two-sample bidirectional and multivariable Mendelian randomization study. Zhang T, Huang J, Zhou L. J Dairy Sci. 2026 Apr 23:S0022-0302(26)00375-9.

• The etiology of obesity is complex, involving genetic, dietary, environmental, behavioral, and psychosocial factors. Diet, as a core modifiable factor, remains a focal point in obesity research and intervention strategies.
• This study aimed to investigate the causal relationship between intake of specific milk and dairy products (whole, semi-skimmed, and skim milk; cream; ice cream; yogurt; cheese) and obesity due to excess calories using genetic instruments.
• A 2-sample bidirectional Mendelian randomization (MR) study was conducted using summary-level data from large-scale genome-wide association studies. Genetic variants associated with dairy intake and obesity were used as instrumental variables.
• The primary analysis used the inverse variance weighted (IVW) method, supplemented by sensitivity analyses to test for pleiotropy and heterogeneity. Multivariable MR (MVMR) was subsequently applied to estimate the independent effect of significant exposures, adjusting for key confounders.
• In univariate MR analyses, genetic predisposition to higher cheese intake was associated with a lower risk of obesity (IVW: P = 0.03, OR = 0.37). No significant causal effects were found for other dairy products, and reverse MR analyses indicated no effect of obesity on dairy intake.
• Sensitivity analyses supported the robustness of these findings. Crucially, in MVMR analysis adjusting for confounding factors, only cheese intake retained a significant inverse association with obesity (IVW: P = 0.01, OR = 0.30), indicating an independent inverse causal association.
• This MR study provides genetic evidence that cheese intake may have an independent, causal role in reducing the risk of obesity due to excess calories. These findings highlight the importance of distinguishing between different types of dairy products in nutritional epidemiological research and suggest that cheese, as a food with relatively high nutrient density, warrants further investigation regarding its potential role in obesity prevention.

Unmelted, melted, and deconstructed Cheddar cheese: effects on the gut microbiome from a human dietary intervention study. Chonnacháin CN, Gibney ER, Feeney EL, FitzGerald JA, et al. Front Microbiol. 2026 Apr 10;17:1702111

• Cheddar cheese is a nutritionally dense food matrix containing nutrients and bioactives with the potential to influence gut microbial characteristics. Food matrices influence nutrient absorption and digestibility, therefore the dairy matrix may affect gut microbial responses to dairy food intake.
• This research aims to identify gut microbial responses to Cheddar cheese consumption, considering aspects of the dairy matrix.
• Secondary analysis was conducted on a subset (n= 69) of participants' data collected during a 6-week parallel 3-armed intervention study. Interventions involved daily consumption of one of the following:
  • (A) 120 g unmelted Cheddar cheese;
  • (B) 120 g melted Cheddar cheese;
  • (C) butter (49 g), calcium caseinate powder (30 g), and Ca supplement (500 mg).
• Demographics, anthropometry, dietary intake and fecal samples were collected at baseline (V1) and post-intervention (V2). Fecal samples underwent 16S rRNA gene sequencing, followed by bioinformatic processing and statistical analysis.
• At V1, 52% were female, mean age was 58.2 ± 5.4 years, with no significant differences between groups or timepoints. Following sequencing, 12,098 unique bacterial taxa in total were identified. Under a False Discovery Rate (FDR) cutoff of 0.1, Dorea(W = 0.568, FDR = 0.079) and Erysipelotrichaceae UCG-003 (W = 0.887, FDR = 0.097) were significantly increased from V1 to V2 in the unmelted cheese group.
• At V2, Bacteroideswas differentially more abundant in the unmelted cheese group, relative to the melted group (W = 0.587, FDR = 0.034). Bacterial alpha diversity (Shannon, Simpson) significantly increased in the unmelted cheese group only from V1 to V2 (p < 0.05). Beta diversity analysis showed a significant group effect considering both timepoints (F = 1.505, p < 0.01).
• Considering V2 only, Principal Coordinate Analysis showed the unmelted group clustered more closely relative to the other groups, although the effect was not significant.
• Unmelted Cheddar cheese modulated the gut microbiome by increasing alpha diversity and abundance of several fermenting bacteria. Overall community structure also became more similar following consumption of unmelted cheese, relative to the other groups.
• In conclusion, heating cheese and altering its physical structure disrupts the dairy matrix, potentially influencing downstream gut-nutrient interactions and subsequent gut microbial response.

Trans fatty acids from dairy foods do not affect risk of cardiometabolic diseases: Systematic review and meta-analysis of evidence from randomized controlled trials and systematic review of prospective cohort studies. Gayet-Boyer C, Tenenhaus-Aziza F, Torres-Gonzalez M, Givens DI, Schweitzer C. Nutr Res. 2026 Mar 27;150:33-48.

• Dairy foods are becoming one of the major dietary sources of trans fatty acids (TFA) as global initiatives to eliminate industrially produced TFA are implemented.
• This systematic review aimed to assess the cardiometabolic effects of TFA from dairy foods, using data from randomized controlled trials (RCTs) and prospective cohort studies (PCS).
• Researchers hypothesized that TFA from dairy foods would have no effect on biomarkers for or risk of cardiovascular diseases. Searches for RCTs and PCS were conducted in PubMed and EMBASE using PRISMA guidelines.
• RCTs compared the impact on blood lipids of regular dairy foods with TFA-enhanced dairy fat/foods produced by altering the cow's diet. Pooled meta-analysis of RCTs using the random effects model was performed for total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), total cholesterol/HDL-C, low-density lipoprotein cholesterol/HDL-C, triacylglycerols, apolipoprotein A1, and apolipoprotein B as continuous variables.
• Selected PCS analyzed associations between blood concentrations of trans vaccenic acid or trans palmitoleic acid and risk of cardiovascular diseases or type 2 diabetes.
• Among 10 RCTs, there were no significant differences in mean difference for any lipid biomarkers except for a slight decrease in HDL-C for TFA-enriched vs. regular dairy foods.
• Among 12 PCS, circulating concentrations of trans vaccenic acid or trans palmitoleic acid were not associated with increased risk of cardiovascular diseases incidence, mortality, or type 2 diabetes.
• In conclusion, the consumption of TFA (1.3-13.2 g/d) from different types of dairy foods was not linked to adverse effects on cardiometabolic health.

Innovation, Social Science, and Dairy Alternatives

 

Extending the shelf life of pasteurized milk through microfiltration and implementation of a comprehensive safety and quality management system: case study at the farm and dairy plant.

Gammoh S, Alu'datt MH, Al-Tawaha A, et al. J Dairy Res. 2026 Apr 21:1-15.

• This study aimed to implement good hygienic practices and good manufacturing practices programmes, together with the hazard analysis critical control points (HACCP) system, to produce extended shelf-life (ESL) pasteurized milk using crossflow microfiltration.
• The microbiological quality of raw milk was markedly improved upon implementation of hygienic prerequisites and HACCP, resulting in a reduction of total colony count (TCC), Staphylococcus aureus, psychrotrophs, yeasts and moulds, spore-forming bacteria, Salmonella, coliforms and Escherichia coli.
• All the milk samples tested negative for antibiotics and aflatoxin M₁.
• Pasteurized and homogenized milk was microfiltered through a 0.8 or 0.45 μm pore-size membrane to produce ESL whole milk and ESL partly skimmed (2%) milk, respectively, resulting in further improvement of refrigerated shelf life to about 2 weeks and 3 weeks, respectively.
• ESL 2% milk showed a significantly lower TCC compared to ESL whole milk, and the latter also had a lower TCC than pasteurized whole milk. Both ESL milk products showed negligible denaturation of α-lactalbumin and β-lactoglobulin.
• The results demonstrate the effectiveness of combining microfiltration with on-farm and in-plant safety management systems for ensuring the safety and quality of ESL pasteurized milk.

Educating consumers about milk processing, code dates and sustainability can impact knowledge, confidence and behavior. Ozoh C, Talbert J, Clark S. J Dairy Sci. 2026 Apr 9:S0022-0302(26)00349-8.

• Confusion around code dates contributes to food waste at the consumer level. In the US, dairy is the second-highest wasted food category.
• This study aimed to 1) evaluate changes in consumer understanding of fluid milk code dates after targeted educational interventions, 2) assess the effectiveness of educational materials on consumer knowledge about pasteurization, ultra-pasteurization, milk code dates, and greenhouse gas emissions by the dairy industry, 3) measure changes in consumer confidence regarding milk quality, safety, and dairy industry sustainability practices, and 4) identify key behavioral and perceptual drivers of milk waste among consumers.
• Milk consumers over 18 (n = 233) participated in one of 20 focus groups held in Ames, Iowa, from February to March 2023. Each group, facilitated by 2-4 facilitators, received one of 3 treatments.
• All received a common treatment, composed of discussion prompts, a code date educational message (EM), and the "Decoding Milk" infographic. The common-treatment control groups (C) only received the common treatment; the sustainability infographic groups (SI) received an add-on sustainability EM and a sustainability infographic; the sustainability video groups (SV) received an add-on sustainability video and the sustainability infographic. Pre- and post-surveys were conducted (n = 233), and a follow-up survey was completed by 177 participants one month later.
• Panelists learned that pasteurization and ultra-pasteurization kill all harmful bacteria but not all spoilage bacteria, and that post-opening, milk should taste good for about 7 d.
• Panelists in the SI and SV groups learned that the US dairy industry contributes 2% of greenhouse gas emissions. Confidence in milk quality and safety, high at pre-survey, significantly increased post-intervention and remained very high at follow-up, regardless of treatment group.
• Confidence that the dairy industry is working to reduce greenhouse gas emissions significantly increased in the SI and SV groups and remained higher than C groups.
• Public EMs can clarify and build trust in code dates as quality indicators, encouraging milk consumption past its code date, and thus help reduce unnecessary milk waste.

Consumer knowledge and motivations for consumption of fermented foods. Hanlon M, Van Beeck W, Wei L, Tosta I, Liao R, Marco ML, DiCaprio E. Front Microbiol. 2026 Apr 10;17:1789825.

• Non-alcoholic fermented foods (FFs) are a popular food group with consumers; however limited studies exist evaluating the motivations for consuming FFs and the frequency of consumption.
• To begin to address this gap in knowledge, researchers developed an online survey to assess participant familiarity with different types of fermented products, determine consumption frequency, and gain insight into the motivation for consumption. A total of 751 participants completed the survey.
• Yogurt was the most frequently identified fermented food (n= 658; 87.62% of respondents). Participants reported consuming fermented cereal grains (n = 307; 46.17%), fruits and vegetables (n = 281; 42.26%), dairy products (n = 204; 39.70%), soy/rice products (n = 250; 37.60%) and fermented meats (n = 204; 30.68%).
• Reported daily consumption was highest for categories of fermented cereal and dairy products, compared to the other categories which typically were consumed on a weekly or monthly basis.
• The primary motivator for consumption was taste (n= 337; 50.68%) compared to health benefits (n = 235; 35.34%) and cultural reasons (n = 80; 12.03%). The most highly selected health benefits associated with FF consumption were "improved gut microbiome" (n = 513; 77.14%), "digestive benefits" (n = 508; 76.39%), and "probiotic" (n = 458; 68.87%).
• Participants associated health benefits with all fermented products listed in the survey. Therefore, consumers may assume that all fermented foods confer the same health benefits. This suggests that consumers view FFs similarly regardless of the starting ingredients and fermentative process involved.

Spatial distribution and socioeconomic correlates of raw milk retail sites in California: A multi-scale analysis of global and local regression models. Wamala H, Okello E. Prev Vet Med. 2026 Apr 18;253:106884.

• Demand for raw (unpasteurized) milk is increasing despite food safety concerns. California, which permits legal retail sales of raw milk, provides a unique setting to examine how socioeconomic conditions influence raw milk availability.
• This study mapped the spatial distribution of raw milk retail sites and assessed associations between county subdivision-level socioeconomic characteristics and retailer availability, rather than consumption or health outcomes.
• Raw milk retailer locations (n = 410) were geocoded and aggregated into 403 California county subdivisions and linked with American Community Survey indicators. Spatial clustering was assessed using Moran's I. Statewide associations were estimated with a mixed-effects negative binomial model. Spatial nonstationarity was explored using geographically weighted regression.
• Retailers were significantly clustered, with concentrations in the Greater Los Angeles Basin and San Joaquin Valley. In the global model, higher proportions of non-Hispanic White residents, households without a vehicle, and adults with at least an associate degree were positively associated with retailer availability.
• Associations varied across space: the effect of households without a vehicle was strongest in Southern California and weak or negative in parts of the north, whereas the percentage of White residents showed a consistently positive association across Central and Southern California.
• Raw milk retail availability in California is uneven and socially patterned. Public health planning and regulatory oversight should account for this spatial heterogeneity.

Understanding the Motivations, Perceptions and Nutritional Implications of Plant-Based Milk Consumption Compared to Dairy-Based Milk. Harmer I, Craddock JC, Lawrence A, McCaffery T, Kent K, Charlton KE.J Hum Nutr Diet. 2026;39(3):e70254.

• Plant-based milks have been increasing in popularity amongst Australian consumers, concurrent with a decrease in cow's milk consumption. Given the key role of cow's milk in Australian diets, it is necessary to understand the motivations behind this consumer behaviour and investigate the nutritional implications associated with this shift in dietary choice.
• Adults, including both omnivores and purposefully targeted vegan individuals, were recruited via social media to complete an online survey and two 24-h dietary recalls using the online Intake24 dietary assessment programme.
• The survey explored milk type choice and participant perceptions of the health and environmental impact of plant-based milks.
• Respondents were divided into groups based on whether they reported to consume or not consume dairy products in the survey. Survey and dietary intake data were then compared between these two groups.
• Of the 217 survey responses received (n = 74 dairy and n = 143 non-dairy consumers), soy, almond and oat plant-based milks were the most popular choices. The primary drivers behind milk type choice were animal rights, self-reported adverse health symptoms and environmental concerns.
• Additionally, non-dairy consumers were more likely to perceive these products as healthier and better for the environment than cow's milk. Dietary intake data identified that overall non-dairy consumers had significantly lower intakes of saturated fat, iodine and vitamin B12 and higher amounts of dietary fibre compared to dairy consumers.
• This study provides novel insights into the motivations to consume, and perceptions of the healthfulness, plant-based milk in Australia and identified that non-dairy consumers may be at increased risk of iodine and vitamin B12 deficiency.