Welcome to the December 2020 Dairy Research Bulletin. The Dairy Research Bulletin delivers a brief synopsis of the most current Human, Animal, and Environmental dairy research that is going on in the World, and also that which is of special interest to California dairy producers and consumers alike.

If you would like to peruse the most pertinent dairy research from months past, then visit the Dairy Research Bulletin Archive.


Selected Articles on Social Responsibility, Environmental Management, and Sustainability

COVID-19 and the agri-food system in the United States and Canada. Weersink A, von Massow M, Bannon N, Thompson J, Wood K, et al. Agric Syst. 2020 Dec 23:103039.

  • Agri-food supply chains in North America have become remarkably efficient, supplying an unprecedented variety of items at the lowest possible cost. However, the initial stages of the COVID-19 pandemic and the near-total temporary loss of the foodservice distribution channel, exposed a vulnerability that many found surprising.
  • Instead of continued shortages, however, the agri-food sector has since moved back to near normal conditions with prices and production levels similar to those typically observed in years prior to the pandemic. Ironically, the specialization in most food supply chains designed for “just-in-time” delivery to specific customers with no reserve capacity, which led to the initial disruptions, may have also been responsible for its rapid rebound.
  • A common theme in assessing the impacts across the six commodities examined is the growing importance of understanding the whole supply chain. Over the longer term, a continuation of the pandemic could push the supply chain toward greater consolidation of firms and diversification of products given the increasing option value of maintaining flexibility. Other structural changes will be felt through input markets, most notably labor, as the trend toward greater automation will continue to accelerate as a response to meeting concerns about a consistent supply of healthy and productive workers.
  • The economic fallout from the pandemic may lead to greater concentration in the sector as some firms are not able to survive the downturn and changes in consumer food buying behavior, including movement toward online shopping and enhanced demand for attributes associated with resiliency, such as local. On the other hand, online shopping may provide opportunities for small producers and processors to shorten supply chains and reach customers directly.
  • In the long term, COVID-19 impacts on global commerce and developing country production are more uncertain and could influence poverty reduction. While COVID-19’s impacts on North American agriculture should have minimal effect on the Sustainable Development Goals (SDGs) through food prices, the ongoing global trends in trade and agribusiness accelerated by the pandemic are relevant for achievement of the SDGs.

Overview of the Potential Impacts of Climate Change on the Microbial Safety of the Dairy Industry. Feliciano RJ, Boué G, Membré JM. Foods. 2020 Dec 3;9(12):1794.

  • Climate change is expected to affect many different sectors across the food supply chain. The current review paper presents an overview of the effects of climate change on the microbial safety of the dairy supply chain and suggest potential mitigation strategies to limit the impact.
  • Raw milk, the common raw material of dairy products, is vulnerable to climate change, influenced by changes in average temperature and amount of precipitation. This would induce changes in the microbial profile and heat stress in lactating cows, increasing susceptibility to microbial infection and higher levels of microbial contamination.
  • Moreover, climate change affects the entire dairy supply chain and necessitates adaptation of all the current food safety management programs. In particular, the review of current prerequisite programs might be needed as well as revisiting the current microbial specifications of the receiving dairy products and the introduction of new pretreatments with stringent processing regimes.
  • The effects on microbial changes during distribution and consumer handling also would need to be quantified through the use of predictive models. The development of models considering the whole farm-to-fork chain to evaluate risk mitigation strategies, will be a key step to prioritize actions towards a climate change-resilient dairy industry.

Microbial quality and safety of milk and milk products in the 21st century. Fusco V, Chieffi D, Fanelli F, Logrieco AF, Cho GS, Kabisch J, Böhnlein C, Franz CMAP. Compr Rev Food Sci Food Saf. 2020 Jul;19(4):2013-2049.

  • Milk and milk products have been utilized by humans for many thousands of years. With the advent of metagenomic studies, our knowledge on the microbiota of milk and milk products, especially as affected by the environment, production, and storage parameters, has increased.
  • Milk quality depends on chemical parameters (fat and protein content and absence of inhibitory substances), as well as microbial and somatic cells counts, and affects the price of milk. The effects of hygiene and effective cooling on the spoilage microbiota have shown that proteolytic and lipolytic bacteria such as Pseudomonas or Acinetobacter spp. predominate the spoilage bacterial populations. These bacteria can produce heat-stable proteases and lipases, which remain active after pasteurization and thus can spoil the milk during prolonged storage.
  • Additionally, milk can become contaminated after pasteurization and therefore there is still a high demand on developing better cleaning and sanitation regimes and equipment, as well as test systems to (quantitatively) detect relevant pathogenic or spoilage microorganisms. Raw milk and raw milk cheese consumption is also increasing worldwide with the growing demand of minimally processed, sustainable, healthy, and local foods.
  • In this context, emerging and re-emerging pathogens once again represent a major food safety challenge. As a result of global warming, it is conceivable that not only microbiological risks but also chemical risks relating to presence of mycotoxins or plant toxins in milk will increase. Herein, we provide an overview of the major microbial hazards occurring in the 21st century.

The Western United States has Greater Antibiotic Resistance Among Salmonella Recovered from Intestinal Cecal Samples of Food Animals. Nyirabahizi E, Tyson GH, Tate H, Williams MS, Saini GS, Strain E. J Food Prot. 2020 Dec 15.

  • As part of the National Antimicrobial Resistance Monitoring System (NARMS) activities, the United States Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) collected cecal samples from food animal slaughter facilities throughout the country between 2014 and 2018.
  • Of the 26,780 cecal samples from cattle, swine, chicken and turkey , 6,350 (23.71%) tested positive for Salmonella . NARMS tested Salmonella for susceptibility to aminoglycosides, folate pathway inhibitors, macrolides, phenicols, quinolones, beta lactams, and tetracyclines.
  • The results show a significant association between region and Salmonella prevalence, when accounting for source and establishment size, with the southeast region having the highest probability of finding Salmonella. However, the western region had the highest resistance probability across all antimicrobial classes except for macrolides, which showed no regional association. This association between region and resistance was strongest among isolates from cattle.
  • Analysis of whole-genome sequencing data indicated that a significantly higher prevalence of Salmonella Newport in cattle in the western region (accounting for 9.52% of cattle isolates, compared to 3.44% in other regions) may account for the greater resistance to multiple drug classes.
  • Thus, differences in resistance across regions may be due to geographical differences in the prevalence of specific Salmonella serotypes and their accompanying resistance genes.

Communication preferences and social media engagement among Canadian dairy producers. Roche SM, Renaud DL, Genore R, Bauman CA, Croyle S, Barkema HW, Dubuc J, Keefe GP, Kelton DF. J Dairy Sci. 2020 Dec;103(12):12128-12139.

  • The objective of this study was to determine communication preferences of dairy producers in Canada. A secondary objective was to evaluate social media engagement of dairy producers.
  • A survey was administered to Canadian dairy producers between March and April, 2015 to collect information on current management practices on their farms. A total of 1,373 Canadian dairy producers responded to the survey, representing a response rate of 12%.
  • The primary outcome variables of interest included use of the internet to access dairy information, importance of different sources of information about dairy herd health and management and use of online search engines and social media platforms.
  • Veterinarians were viewed as a “very important” source of information by the majority of respondents (79%), whereas milk recording and dairy producer organizations were viewed as a “very important” source of information by 36% of respondents. Other producers (46%) and magazines or newspapers (51%) were commonly viewed as an “important” source of information.
  • Online search engines were commonly used by respondents (94%). Social media was viewed as less important, and had mixed levels of use. YouTube (70%), Facebook (63%), and Twitter (18%) were the most commonly used social media platforms. Eighty percent of Twitter users reported using the platform to interact with and obtain or share information about herd health management online, which was the highest reported interactivity regarding herd health among all social media platforms.
  • This exploratory study offers insight into the communication preferences of Canadian dairy producers and can be used to facilitate future communication strategies aimed at engaging rural farming audiences across Canada.


Selected Articles on Dairy Intake and Human Health

Beverage milk consumption patterns in the United States: Who is substituting from dairy to plant-based beverages? Wolf CA, Malone T, McFadden BR. J Dairy Sci. 2020 Dec;103(12):11209-11217.

  • Long-term trends of declining beverage milk consumption have been exacerbated in recent years by increasing consumption of plant-based beverages. Although beverage milk consumption has been declining, total dairy consumption in the United States continues to increase, driven by growth in sales of cheese, butter, and yogurt.
  • This research used a survey of 995 US households to explore how dairy milk and plant-based beverage substitutes were consumed. Using k-means cluster analysis, 3 consumption clusters for US households were identified.
  • The largest cluster, consisting of 61.6% of households, consumed dairy milk with some regularity and consumed little or no plant-based beverages. A second cluster, flexitarian households, consisting of 15.6% of respondent households, frequently consumed both dairy milk and plant-based beverages. The third cluster, plant-based consumers, consisting of 22.8% of households, consumed almost exclusively plant-based beverages.
  • Examining differences in demographics between clusters, flexitarian households were larger, more likely to include young children, more likely to include a vegetarian or vegan, and more liberal than traditional dairy-consuming households. Plant-based households had many similarities to flexitarian households. The flexitarian and plant-based clusters were willing to substitute plant-based beverages for dairy milk for almost all consumption uses.

A Nutritional Comparison of Cow’s Milk and Alternative Milk Products. Collard KM, McCormick DP. Acad Pediatr. 2020 Dec 26:S1876-2859(20)30648-3.

  • Alternative milk products are becoming more visible and popular, but nutrient data to compare these products to traditional cow’s milk are not easily accessible. By summarizing this nutritional information, this project aims to help primary care providers take better care of their patients by providing easy to access nutritional comparison between cow’s milk and milk alternatives such as plant-based milks and goat’s milk.
  • This project uses data from The United States Department of Agriculture (USDA)’s Food Data Central database and publicly available nutrition label data to compare the nutritional content of selected milk.
  • Almond and oat milks provide less than half of the protein provided by soy, goat’s, and cow’s milk. Goat’s milk contains the most fat of the products surveyed, while skim milk contains the lowest fat per serving. Soy milk, almond milk, and oat milk contain at least half the fat of cow’s milk.
  • Almond milk contained the most calcium of the milks surveyed. Quantities of folate and vitamin B12 were most notably decreased in goat’s milk and almond milk while soy milk had almost double the amount of folate and vitamin B12 present in cow’s milk.
  • Cow’s milk still remains the best source of fats, protein, and micronutrients. For parents who prefer an alternative to cow’s milk, the child’s health should be considered. Parents may consider nutrition information when making decisions for their families, and primary care pediatricians should be able to provide current nutritional data on frequently advertised products.

Fermented milk containing Lactobacillus casei Zhang and Bifidobacterium animalis ssp. lactis V9 alleviated constipation symptoms through regulation of intestinal microbiota, inflammation, and metabolic pathways. Wang J, Bai X, Peng C, Yu Z, Li B, Zhang W, Sun Z, Zhang H. J Dairy Sci. 2020 Dec;103(12):11025-11038.

  • Studies suggest that probiotics and fermented milk can improve defecation in constipated patients. However, the mechanism of fermented milk containing probiotics on constipation remains poorly understood.
  • Volunteers with chronic constipation symptoms were recruited and given 200 g/d of fermented milk containing Lactobacillus casei Zhang and Bifidobacterium animalis ssp. lactis V9 (PFM) for 4 weeks.
  • Clinical symptoms, cytokines, metagenomics, and metabolomics were evaluated in constipated participants before and after PFM intervention. After PFM intervention, researchers observed significant improvement of constipation symptoms. In the serum samples, the anti-inflammatory cytokine IL-10 increased and the proinflammatory cytokine C-reactive protein and lipopolysaccharides decreased.
  • Metagenomics results showed that the increase of animalis was correlated with an increase in defecation frequency. Fatty acid biosynthesis and bile acid biosynthesis in stool samples as well as carnitine shuttle, vitamin E metabolism, and ascorbate and aldarate metabolism were identified as significantly altered metabolic pathways. Acylcarnitine, located on the carnitine shuttle pathway, had a significantly positive correlation with defecation frequency.
  • It was speculated that PFM may contribute to alleviating constipation symptoms through 3 potential mechanisms: fine-tuning gastrointestinal microbiota, fighting inflammation, and regulating metabolic pathways.

The anticarcinogenic potential of milk fat. Cichosz G, Czeczot H, Bielecka M. Ann Agric Environ Med. 2020 Dec 22;27(4):512-518.

  • The anticarcinogenic potential of milk fat can be attributed to its antioxidant, anti-inflammatory, immunostimulatory properties as well as the presence of compounds with antimutagenic effects.
  • In view of the high incidence of cancer the aim of this article was to review the literature concerning the biological activity of milk fat components. Brief description of the state of knowledge: Conjugated linoleic acid (CLA), coenzyme Q10, phospholipids, β-carotene, and vitamins A, D and E play an important role in the pro-oxidant/antioxidant homeostasis.
  • The anti-inflammatory properties of milk fat can be attributed to the presence of phospholipids and short- and medium-chain saturated fatty acids. Conjugated linoleic acid has immunostimulatory properties, and it influences the proliferation and activity of lymphocytes and macrophages.
  • Saturated (C10 and C12) and unsaturated (C18) fatty acids, as well as sphingolipids, exert bactericidal effects in the gastrointestinal tract. Vaccenic acid, CLA and sphingomyelin possess antimutagenic and anticarcinogenic properties. Butyric acid promotes the apoptosis of cancer cells in the liver, and delivers positive effects in the treatment of breast and colorectal cancer.
  • Alkylglycerols activate macrophages, stimulate phagocytosis and, most importantly, the apoptosis of cancer cells. The health benefits of milk fat are not fully exploited due to its low consumption. Therefore, only some epidemiological studies have shown a negative correlation between the consumption of high-fat dairy products and the incidence of cancer.
  • More research is needed involving human clinical trials to allow a better understanding of the anticancer biochemistry related with milk fat compounds.

The Effects of Milk and Dairy Products on Sleep: A Systematic Review. Komada Y, Okajima I, Kuwata T. Int J Environ Res Public Health. 2020 Dec 16;17(24):9440.

  • Several studies have assessed the effects of milk and dairy product intake on sleep quality and duration. Such investigations have varied in terms of their geographic locations, amounts of milk and dairy products, study participants (age, sex, race), and study designs.
  • The present study aimed to summarize this literature and provide a unified view on whether the intake of milk and dairy products affects sleep quality.
  • This systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The following keywords were chosen as electronic database search items: milk, yogurt, dairy product, cheese, sleep, human, observational study, and interventional study.
  • As a result, a total of 14 studies published between 1972 and 2019 were included in this review, including eight randomized controlled trials, two experimental studies with cross-over designs, one longitudinal study, and three cross-sectional studies. Four studies targeted older adults, three included toddlers, two targeted children, and six enrolled adults inclusive of university students.
  • Overall, these studies indicated that a well-balanced diet that includes milk and dairy products is effective in improving sleep quality, despite mixed results across studies attributable to differences in study populations and methods.

Meta-analysis of randomized controlled trials on calcium supplements and dairy products for changes in body weight and obesity indices. Hong JY, Lee JS, Woo HW, Om AS, Kwock CK, Kim MK. Int J Food Sci Nutr. 2020 Dec 8:1-17.

  • This meta-analysis was performed to investigate whether calcium supplements and dairy products change obesity indices including fat mass.
  • Original articles published in English between July 2009 and August 2019 were identified. Ten and 14 randomized controlled trials (RCTs) with ≥ 12 weeks interventions of calcium supplements and dairy products among overweight or obese adults aged ≥18 were critically reviewed.
  • Dairy products significantly changed fat mass and BMI, and calcium supplements also showed minor changes in fat mass. However, in the analysis of RCTs with low risk of bias scores, the significant changes remained only in the dairy-products intervention.
  • Our findings suggest that dairy products without distinction of fat percentage may help reduce fat mass and BMI, but calcium supplements may not.