Agricultural Research Service (ARS) scientists have helped confirm that Escherichia coli is not likely to contaminate the internal vascular structure of field-grown leafy greens, which would be likely to increase the incidence of foodborne illness. There was no evidence that E. coli had become "internalized" in leaves or shoots of baby spinach plants 28 days after the plants had germinated and grown in pasteurized soil. E. coli could be detected in hydroponically-grown spinach samples, but its survival in shoot tissue was sporadic.
For details, contact: Manan Sharma, (301) 504-9198, Environmental Microbial and Food Safety Laboratory, ARS Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, Md.
Spinach leaves exposed to continuous light during storage were, overall, more nutritionally dense than leaves exposed to continuous dark, according to an Agricultural Research Service (ARS) study. Researchers exposed spinach leaves to light similar to the 24-hour artificial fluorescent light received by spinach in packages located at the front of the display case. A second group was enclosed in two-layer-thick, brown-grocery-bag paper to represent the "dark treatment." The researchers found that the continuous light affected the leaves' photosynthetic system, resulting in a significant increase in levels of carotenoids and vitamins C, E, K, and B9, or folate.
Laboratory hamsters that were fed rations spiked with blueberry peels and other blueberry-juice-processing leftovers had better cholesterol health than hamsters whose rations weren't enhanced with blueberries. All of the hamsters that were fed blueberry-enhanced rations had from 22 to 27 percent lower total plasma cholesterol than hamsters fed rations that didn't contain blueberry juice byproducts. Levels of VLDL (very low density lipoprotein—a form of "bad" cholesterol) were about 44 percent lower in the blueberry-fed hamsters. Further research is needed to confirm whether the effects observed in hamsters hold true for humans.
Agricultural Research Service (ARS) researchers examined 1,186 samples of beef "trim"—the meat that's left over after steaks and roasts have been carved from a side of beef—from the United States and from Australia, New Zealand and Uruguay, three nations that provide more than half of America's beef imports, for bacterial contamination to test current diagnostic procedures. The research had been requested because questions had been raised as to whether America's procedures for monitoring the safety of imported beef trim were adequate for detecting pathogens such as E. coli in trim. The researchers looked for contaminants such as Staphylococcus aureus, Campylobacter, Salmonella, Listeria, and near relatives of E. coli O157:H7 that can cause severe foodborne illness. Results indicated that the pathogen-monitoring procedures used in the United States today are adequate for evaluating the safety of imported beef trim.
The pros and cons of using wet distiller's grains with solubles (WDGS)—what's left of corn after it is processed to make ethanol—as a cattle feed ingredient are being studied by Agricultural Research Service (ARS) scientists. Experiments showed that the incidence and prevalence of E. coli O157:H7 in manure, and the incidence on hides, was significantly higher for cattle whose corn-based feed included 40 percent WDGS than those whose feed did not include WDGS. In follow-up studies, the researches want to determine what causes the difference in E. coli levels, and what can be done to reduce them.
New techniques that will decontaminate clams, mussels, and oysters while protecting the mollusks' flavor, texture, and color are being explored by Agricultural Research Service (ARS) scientists. A specialized commercial procedure known as high pressure processing, or HPP, can inactivate viruses. HPP is already used commercially to pasteurize some juices and meats, and by some shellfish processors to deactivate Vibrio bacteria. But this study was the first to show that HPP also can inactivate some foodborne viruses.
The idea that herbal teas may provide a variety of health benefits is not just folklore. A survey of the research literature on the health benefits from drinking three of the most popular herbals in America—chamomile, peppermint, and hibiscus tea—found compelling science-based evidence. While there was no clinical evidence for a calming effect from chamomile tea, test-tube evidence of moderate antimicrobial activity and significant antiplatelet-clumping activity was found. In test tubes, peppermint tea has been found to have significant antimicrobial and antiviral activities, strong antioxidant and antitumor actions, and some antiallergenic potential. Based on a human clinical trial, drinking hibiscus tea was found to have lowered blood pressure in a group of pre-hypertensive and mildly hypertensive adults.
In the past few years, a half-dozen emerging E. coli species, also called serogroups, have come to be known among food safety specialists as "the Big Six," namely E. coli O26, O45, O103, O111, O121, and O145. Researchers are sorting out "who's who" among these related pathogens so that the microbes can be quickly and reliably detected and identified. A group led by Agricultural Research Service (ARS) scientists has developed gene-based PCR (polymerase chain reaction) assays for each of the Big Six. With further work, the assays might be presented as user-friendly test kits for use by regulatory agencies and others. Analyses of test results also might help researchers determine whether certain strains of Big Six E. coli species cause more illness than E. coli O157:H7 does, and if so, why.
For details, contact: Pina M. Fratamico, (215) 233-6525, Molecular Characterization of Foodborne Pathogens Unit, ARS Eastern Regional Research Center, Wyndmoor Penn.
Initial Agricultural Research Service (ARS) studies suggest that dietary yeast extract has good potential as a non-antibiotic alternative for decreasing pathogens in organic turkey production. Yeast extracts help boost the immune system's ability to kill bacteria, but there is also a downside. Yeast ramps up certain aspects of the immune response, but body weight may be decreased in some birds.
For details, contact: Geraldine R. Huff, (479) 575-7966, ARS Poultry Production and Product Safety Research Unit, Fayetteville, Ark.
Agricultural Research Service (ARS) scientists have developed and patented an experimental, cutting-edge optical scanning system that would use two different kinds of lighting, a sophisticated camera and other pieces of equipment to scrutinize produce-section favorites like apples while they are still at the packinghouse. The system would provide, in a single image, evidence of certain kinds of defects, which could include cuts and bruises, and contaminants, which might include specks of fertilizer from orchard or field soil.
For details, contact: Moon S. Kim, (301) 504-8450, ext. 245, Environmental Microbial and Food Safety Research Laboratory, ARS Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, Md.