Researchers developing omega-3-fortified milk

Researchers developing omega-3-fortified milk

*Krissa Welshans holds a bachelor's degree in animal science from Michigan State University and a master's degree in public policy from New England College. Welshans has long been involved in agriculture and has worked with numerous agricultural groups, including the Animal Agriculture Alliance.

FISH oil is a natural source of heart-healthy omega-3 fatty acids, but not everyone can stomach the taste.

While a growing number of foods enriched with omega-3s may provide alternative options for health-conscious people, milk hasn't been one of those options.

Now, food science researchers at Virginia Polytechnic Institute & State University may have reeled milk into the omega-3 delivery system by showing that it is possible to incorporate fish oil into milk and dairy-based beverages in amounts sufficient enough to promote heart health without destroying the product's taste or limiting its shelf life.

Even better, the milk passes the sniff test. Twenty-five volunteers evaluated 1 oz. cups of standard 2% milk alongside samples of skim milk containing 78 parts butter oil to 22 parts fish oil in institutionally approved study conditions.

"We couldn't find any aroma differences," said Susan E. Duncan, a professor of food science and technology in the Virginia Tech College of Agriculture & Life Sciences. "We were concerned that the fish oil would undergo a chemical process called oxidation, which would shorten the milk's shelf life, or the milk would acquire a cardboard or paint flavor by reacting with the fish oil. It appears we have a product that is stable, with no chemical taste or smell issues."

The study, featured in the November issue of the Journal of Dairy Science, tested four different ratios of butter oil to fish oil in the production of pasteurized, fatty acid-fortified beverages.

The aroma-free formulation delivered 432 mg of heart-healthy fatty acids per cup, which is close to the 500 mg daily target for healthy people suggested by a broad range of health studies.

The U.S. Department of Agriculture suggests daily consumption of 250 mg per day in healthy adults.

Research has shown that omega-3 fatty acids are helpful for preventing coronary disease, reducing inflammation, assisting with infant brain development and maintaining brain function.

Meanwhile, the American Heart Assn. recommends eating two servings of fatty fish per week, citing research showing that omega-3 fatty acids decrease the risk of potentially fatal heart arrhythmias, decrease triglyceride levels, slow the growth of atherosclerotic plaque and slightly lower blood pressure.

Fish hasn't caught on with everyone, though, which means that there's room for new foods and beverages fortified with omega-3s in an expanding marketplace. Sales are expected to reach more than $3 billion in 2016, according to marketing analysts.

"I think the dairy industry can look at our study and determine whether it is plausible to modify its products," Duncan said. "I would like to help people who love milk, yogurt and dairy -- which have intrinsic nutritional value -- address an additional need in their diets, especially if they don't like to eat fish or can't afford it. One of these dairy servings a day apparently is enough to sustain enough continuous omega-3 to benefit heart health."

If such a product catches on with consumers, Duncan said the next step for researchers is to follow groups of volunteers in an epidemiological study of whether the food improves health outcomes.

"Milk was first fortified with vitamin D as a way to fight rickets, a disease that leads to soft or weak bones," said Kerry E. Kaylegian, a dairy foods research and extension associate with The Pennsylvania State University College of Agricultural Sciences who was not involved in the research. "It was a good approach to address a dietary deficiency disease because so many people drink milk, which is already loaded with nutrients.

"This study describes fortification of milk with the omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid). We can't say lack of those compounds definitively causes cardiac disease, but there is evidence that they protect us and contribute to heart and brain health. Milk would be a good delivery vehicle for those nutrients," Kaylegian added.


E. coli sources

New findings from USDA's Agricultural Research Service (ARS) are relieving livestock farms from taking all of the blame for Escherichia coli.

Even though most strains of E. coli are non-pathogenic, the bacterium is monitored by public health officials as an indicator of water quality. Cows are often seen as the culprits when E. coli is found in local lakes, rivers and other bodies of water.

Studies by ARS scientist Mark Ibekwe suggest that in some parts of California, pathogens in local waterways are more often carried there via runoff from urban areas, not from animal production facilities.

Ibekwe, who works at the ARS U.S. Salinity Laboratory in Riverside, Cal., and his colleagues collected 450 water and sediment samples from 20 sites throughout California's middle Santa Ana River Watershed. The collection sites included urban areas, livestock feeding areas, parks, national forestlands and three wastewater treatment plants.

The scientists then extracted E. coli bacteria from each sample and identified 600 different isolates of E. coli in their samples, many of which could be placed into six clonal populations.

They found the greatest variety of different types of E. coli in runoff discharged from areas dominated by urban development or human activities.

Ibekwe also tested all of the E. coli isolates for resistance to various antibiotics. He found that anywhere from 88% to 95% of the isolates were resistant to rifampicin, and around 75% were resistant to tetracycline. Tetracycline resistance was by far the most common type of resistance observed in E. coli isolates collected near wastewater treatment plants.

Additionally, the scientists discovered that 24% of E. coli collected in sediment samples associated with urban runoff -- a total of 144 isolates -- showed resistance to as many as seven antibiotics.

Finally, Ibekwe said he was surprised when they found 53 E. coli isolates that, based on DNA fingerprinting, they could not assign to any of the six clonal groups, but, like the other isolates, these 53 outliers showed a range of resistance to several antibiotics.

The sheer range of different antibiotic-resistant E. coli isolates identified by Ibekwe and his colleagues suggests that public health officials who track water quality might need to increase their database of E. coli fingerprints.

"If we want to use (pulsed field gel electrophoresis) for source tracking in a large watershed like the Santa Ana River, a very extensive DNA fingerprint library is needed, because our study shows that even a minor change in the DNA fingerprint can significantly affect clonal groupings," Ibekwe explained.

"The fingerprint library will have to include isolates from potential multiple-contaminant sources and isolates that vary over time and space throughout the watershed. This will help in correctly identifying isolates that are a health concern," he added.


Dairy fights gum disease

If left untreated, periodontal (gum) disease, or periodontitis, may lead to tooth loss. The disease, which affects a significant number of older adults, is caused by a bacterial infection that induces the breakdown of the connective tissue that anchors teeth to alveolar bone.

Researchers in Denmark have found that a higher intake of dairy calcium -- calcium from milk and fermented foods like yogurt and lactic acid beverages -- was associated with a significantly reduced risk of periodontal disease in a subgroup of 135 older adults (ages 65 and older) enrolled in the "Copenhagen Oral Health Senior Study."

The study population was comprised of 53% women, and the ages ranged from 66 to 95 years. Total dietary calcium intake, excluding daily supplementation, ranged from 309 mg to 3,373 mg.

Only 5% of the population reported daily intake of calcium supplements. Dairy foods were the major source of dietary calcium, accounting for 56% of total calcium intake.

According to the authors, the results are consistent with earlier studies of dairy foods and periodontitis. The findings reinforce that intake of dairy foods rich in calcium and other nutrients may be important for promoting oral health.

Volume:84 Issue:51

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