US Dairy Products Research Articles

Consumer understanding of fluid milk and cheese processing and composition

Ultrafiltration and microfiltration are 2 types of membrane filtration commonly used by the dairy industry. Filtered milk products are becoming increasingly common, but there is concern that consumers unfamiliar with these processing methods may form negative uninformed perceptions of cheeses made with these milks. There are many studies that address the chemical and physical properties of cheeses made with filtered milk, but, to our knowledge, there are none that address consumer perception of these products. Similarly, ultrapasteurization is becoming more common for US dairy products. Although previous work has characterized consumer liking of ultrapasteurized milks, few have investigated understanding and perception of this process. The objective of this study was to explore consumer understanding of milk processing and constituents, particularly as it relates to milk used as an ingredient in cheese. To achieve this goal, we investigated the following 4 questions: (1) Does the average dairy product consumer understand the basic ingredients and nutrients in fluid milk and cultured dairy products? (2) Does the average dairy product consumer understand the basic processes for fluid milk and cultured dairy products? (3) Do different processes affect consumer perception or purchase intent? (4) Does explaining a process change consumer understanding of, beliefs about, and purchase intent for dairy products? Qualitative interviews (n = 54) and an online survey (n = 1,210) were conducted with dairy product consumers. Survey responses paralleled those from one-on-one interviews. The average dairy product consumer could recall key words related to dairy processing, composition, nutrients, and ingredients, but was largely unfamiliar with these subjects. Highly educated and older consumers were more likely to have a better understanding of dairy composition and nutrition, particularly lactose content of milk and Cheddar cheese and the source of fluid whey and whey protein. Processing-related descriptors (e.g., ultrapasteurized or ultrafiltered) in ingredient statements were likely to be overlooked on labels (especially for familiar products), as just 34% of dairy product consumers read the labels on dairy products often or always before purchase. The majority (>80%) of dairy product consumers were unfamiliar with ultrafiltered or microfiltered milk, but uninformed perceptions were generally positive. Consumers unfamiliar with processing methods were likely to assume those methods increase the price of a dairy product. For the majority of consumers, purchase intent for fluid milk and cultured dairy products was not affected when nonconventional processing terms such as ultrafiltered or microfiltered were included in the ingredients statement. This effect was consistent for fluid milk and Cheddar cheeses but not for cottage cheese, suggesting the possibility of product-specific effects. Providing respondents with a definition of filtration increased consumer understanding of, positive beliefs about, and purchase intent for fluid filtered milk and cheese made with filtered milk. Educating consumers through on-package labeling and other marketing messaging should be investigated for dairy products that incorporate processes such as ultrapasteurization or filtration.

Inhibition of methanogenesis by nitrate, with or without defaunation, in continuous culture

Within the rumen, nitrate can serve as an alternative sink for aqueous hydrogen [H2(aq)] accumulating during fermentation, producing nitrite, which ideally is further reduced to ammonium but can accumulate under conditions not yet explained. Defaunation has also been associated with decreased methanogenesis in meta-analyses because protozoa contribute significantly to H2 production. In the present study, we applied a 2 × 2 factorial treatment arrangement in a 4 × 4 Latin square design to dual-flow continuous culture fermentors (n = 4). Treatments were control without nitrate (-NO3-) versus with nitrate (+NO3-; 1.5% of diet dry matter), factorialized with normal protozoa (faunated, FAUN) versus defaunation (DEF) by decreasing the temperature moderately and changing filters over the first 4 d of incubation. We detected no main effects of DEF or interaction of faunation status with +NO3-. The main effect of +NO3- increased H2(aq) by 11.0 µM (+117%) compared with -NO3-. The main effect of +NO3- also decreased daily CH4 production by 8.17 mmol CH4/d (31%) compared with -NO3-. Because there were no treatment effects on neutral detergent fiber digestibility, the main effect of +NO3- also decreased CH4 production by 1.43 mmol of CH4/g of neutral detergent fiber degraded compared with -NO3-. There were no effects of treatment on other nutrient digestibilities, N flow, or microbial N flow per gram of nutrient digested. The spike in H2(aq) after feeding NO3- provides evidence that methanogenesis is inhibited by substrate access rather than concentration, regardless of defaunation, or by direct inhibition of NO2-. Methanogens were not decreased by defaunation, suggesting a compensatory increase in non-protozoa-associated methanogens or an insignificant contribution of protozoa-associated methanogens. Despite adaptive reduction of NO3- to NH4+ and methane inhibition in continuous culture, practical considerations such as potential to depress dry matter intake and on-farm ration variability should be addressed before considering NO3- as an avenue for greater sustainability of greenhouse gas emissions in US dairy production.

Multiple Vitamin K Forms Exist in Dairy Foods

BackgroundThe plant-based form of vitamin K (phylloquinone, vitamin K-1) has been well quantified in the US diet. Menaquinones (vitamin K-2) are another class of vitamin K compounds that differ from phylloquinone in the length and saturation of their side chain, but they have not been well characterized in foods. ObjectivesThe objectives of this study were to 1) quantify phylloquinone and the different forms of menaquinones [menaquinone (MK) 4–MK13] in milk, yogurt, Greek yogurt, creams, and cheeses and 2) compare the menaquinone contents of full-fat, reduced-fat, and nonfat dairy products. MethodsAll dairy samples were either obtained from the USDA National Food and Nutrient Analysis Program or purchased from retail outlets. Phylloquinone and menaquinone concentrations in these dairy products were quantified by mass spectrometry technology. ResultsFull-fat dairy products contained appreciable amounts of menaquinones, primarily in the forms of MK9, MK10, and MK11. We also measured modest amounts of phylloquinone, MK4, MK8, and MK12 in these products. In contrast, there was little MK5–7 or MK13 detected in the majority of dairy products. The total vitamin K contents of soft cheese, blue cheese, semi-soft cheese, and hard cheese were (means ± SEMs): 506 ± 63, 440 ± 41, 289 ± 38, and 282 ± 5.0 µg/100 g, respectively. Nonfermented cheeses, such as processed cheese, contained lower amounts of vitamin K (98 ± 11 µg/100 g). Reduced-fat or fat-free dairy products contained ∼5–22% of the vitamin K found in full-fat equivalents. For example, total vitamin K contents of full-fat milk (4% fat), 2%-fat milk, 1%-fat milk, and nonfat milk were 38.1 ± 8.6, 19.4 ± 7.7, 12.9 ± 2.0, and 7.7 ± 2.9 µg/100 g, respectively. ConclusionsTo the best of our knowledge, this is the first report of menaquinone contents of US dairy products. Findings indicate that the amount of vitamin K contents in dairy products is high and proportional to the fat content of the product.

An economic evaluation of market development programmes for US dairy products

ABSTRACT‘This study measured the effectiveness of US dairy export promotion programmes on increasing foreign demand and enhancing producers’ revenues. An import demand equation based on panel data was used to test whether export promotion has a positive and significant impact on US dairy exports. The effects of various promotion scenarios on the dairy market were then simulated, and benefit–cost ratios (BCRs) for these programmes were estimated. There were three key findings. First, the combined effort of public and private dairy export promotion expenditures had a positive and statistically significant impact on demand for US dairy products in the world market. The findings indicated that export promotion stimulated total dairy exports by 4.14 billion pounds, on average, per year, which represented 55.8% of total exports. Second, US dairy export promotion has been highly profitable for the nation’s dairy farmers. The calculated BCRs, based on assumed elasticity of supply, ranged from a low of 8.54 for the most elastic assumption to a high of 30.12. Third, from an optimality standpoint, dairy farmers are underinvesting in export promotion. The marginal BCRs ranged from a low of 3.79 to a high of 15.22, which means that, at the margin, increasing export promotion expenditures would be profitable for dairy farmers.

Sexualized violence and the gendered commodification of the animal body in Pacific Northwest US dairy production

This article draws on a case study of bovine life in the US dairy industry to observe the power relations and violent networks of commodification involved. I use the terms gendered commodification and sexualized violence to understand the lives of animals in the industry and the discourses that are employed to reproduce its practices. Focusing on sex and gender, concepts which have long been classic in feminist geography, this article explores the sexually violent commodification of both female and male animals in dairy production. In addition to the ways in which both are exploited for their productive and reproductive capacities, male animals are also discursively conceptualized as perpetrators of the violence against the females. This article engages with geographies of the body and animal geographies in order to extend geographies of the body to other-than-human bodies and in order to feature the body more prevalently in animal geographies. This attention to the animal body ultimately reveals the pervasiveness of sexual violence and the consequences of gendered commodification for both nonhuman and human others.

Geospatial analysis of potential water use, water stress, and eutrophication impacts from US dairy production

Water resource impacts from US dairy production include water use (scarcity impacts) and water quality (eutrophication impacts). These impacts are location-specific, depending upon characteristics of the region and watershed where on-farm dairy and feed production occurs. The objectives of this analysis were to evaluate the impact of US on-farm dairy production on water scarcity across the US, and evaluate dairy production's impact on eutrophication processes within watersheds as well as on the Gulf of Mexico hypoxic zone. The primary water-utilization challenge for dairy producers is irrigation for growing feed rather than on-farm use. Most dairy production in the US does not occur in water stressed areas with the exception of production in some western states. The potential impacts on local (P pollution) and regional (N pollution to the Gulf of Mexico) watershed eutrophication are more likely to occur from feed production than from on-farm dairy activities.

Productivity growth patterns in US dairy products manufacturing plants

We analyse the productivity growth patterns in the US dairy products industry using the Census Bureau's plant-level data set. We decompose Total Factor Productivity (TFP) growth into the scale and technical change components and analyse variability of plants’ productivity by constructing transition matrices. We observe a cross-sectional dispersion in plant-level productivity growth in the industry. Even though the industry aggregate shows a small TFP growth rate −0.3%, quartile rank analysis shows that while the lowest productivity quartile plants average 1.9% loss in productivity, the highest productivity quartile plants average 1.1% growth annually. Our results show considerable movements of plants in their productivity rank categories overall and across age groups, and we find that the scale effect contribution to TFP growth accounts for about 90% of TFP growth on average in the industry. These plants extract scale efficiencies over technological progress to fuel TFP growth. The youngest plants start with the lowest productivity growth at the initial time period, but they catch up older plants productivity, which present the highest average growth rate through years. This may indicate a ‘learning-by-doing’ process for the industry.

The environmental impact of dairy production: 1944 compared with 20071

A common perception is that pasture-based, low-input dairy systems characteristic of the 1940s were more conducive to environmental stewardship than modern milk production systems. The objective of this study was to compare the environmental impact of modern (2007) US dairy production with historical production practices as exemplified by the US dairy system in 1944. A deterministic model based on the metabolism and nutrient requirements of the dairy herd was used to estimate resource inputs and waste outputs per billion kg of milk. Both the modern and historical production systems were modeled using characteristic management practices, herd population dynamics, and production data from US dairy farms. Modern dairy practices require considerably fewer resources than dairying in 1944 with 21% of animals, 23% of feedstuffs, 35% of the water, and only 10% of the land required to produce the same 1 billion kg of milk. Waste outputs were similarly reduced, with modern dairy systems producing 24% of the manure, 43% of CH(4), and 56% of N(2)O per billion kg of milk compared with equivalent milk from historical dairying. The carbon footprint per billion kilograms of milk produced in 2007 was 37% of equivalent milk production in 1944. To fulfill the increasing requirements of the US population for dairy products, it is essential to adopt management practices and technologies that improve productive efficiency, allowing milk production to be increased while reducing resource use and mitigating environmental impact.

Beyond Equal: From Same But Different to the Doctrine of Substantial Equivalence

A same-but-different dichotomy has recently been encapsulated within the ill-defined concept of “substantial equivalence”. By invoking this concept the genetically modified organism (GMO) industry has escaped the rigors of safety testing that might otherwise apply. The curious concept of “substantial equivalence” grants a presumption of safety to GMO food. This presumption has yet to be earned, and has been used to constrain labelling of both GMO and non-GMO food. It is an idea that well serves corporatism. It enables the claim of difference to secure patent protection, while upholding the contrary claim of sameness to avoid labelling and safety scrutiny. It offers the best of both worlds for corporate food entrepreneurs, and delivers the worst of both worlds to consumers. The term “substantial equivalence” has established its currency within the GMO discourse. As the opportunities for patenting food technologies expand, the GMO recruitment of this concept will likely be a dress rehearsal for the developing debates on the labelling and testing of other techno-foods - including nano-foods and clone-foods.

Benefits of the National Dairy Council to the Dairy Processing Industry

The National Dairy Council® and its affiliated units have had a vital role in presenting the nutritional qualities of US dairy products to a variety of audiences. Established in 1915, National Dairy Council has been the segment of the dairy industry that initiates and administers nutrition research, implements cutting-edge educational programs, and communicates about the nutritional merits of dairy products to educators, health professionals, consumers, and other important groups. The grassroots structure of National Dairy Council allows it to communicate these important messages at both the national and local levels.

Influence of Fat and Emulsifiers on the Efficacy of Nisin in Inhibiting Listeria monocytogenes in Fluid Milk

The recent FDA affirmation of nisin, an antimicrobial peptide, as a GRAS (generally recognized as safe) additive in pasteurized cheese spreads has renewed interest in its potential application in US dairy products. Fluid milks were prepared with varying concentrations of milk fat (0 to 12.9%) and of nisin (0 to 50 U/ml). Biological activity assays using a sensitive indicator microorganism in a well diffusion system indicated that initial nisin activity (50 U/ml) decreased by about 33% when it was added to skim milk and by more than 88% when added to milk containing 12.9% fat. Nisin activity decreased by ca. 50% in milk containing 1.29% fat. Milks containing 0, 10, or 50 U/ml of nisin and varying fat percentages were challenged with approximately log10 7 to 7.5 cfu/ml of log phase Listeria monocytogenes Scott A or Jalisco. At 2h after inoculation, the viable count of L. monocytogenes Scott A decreased to log10 .30 cfu/ml in skim milk with 50 U/ml of nisin, decreased to log10 2.90 cfu/ml in skim milk with 10 U/ml of nisin, and increased slightly (log10 7.8 cfu/ml) in skim milk without nisin. In half-and-half (12.9% milk fat), nisin was far less effective in inhibiting Listeria with populations decreasing to log10 6.57 cfu/ml for 10 U/ml of nisin and log10 5.87 cfu/ml for 50 U/ml. Similar results were obtained with L. monocytogenes Jalisco. The nonionic emulsifier, Tween 80, partially counteracted decreases of nisin activity in milks, whereas the anionic emulsifier, lecithin, had no effect. Addition of Tween 80 significantly increased the activity of nisin against L. monocytogenes in milk regardless of fat content.