New research on food storage, mammograms

Color-coded tags may signal food’s freshness

Scientists have now come up with a color-coded smart tag that can tell consumers whether a carton of milk has turned sour. This technology could also tell you if a can of green beans has spoiled, all without opening the containers.

“This tag, which has a gel-like consistency, is really inexpensive and safe, and can be widely programmed to mimic almost all ambient-temperature deterioration processes in foods,” said lead researcher Chao Zhang, who is with Peking University in Beijing, China.

The tag, which would appear on the packaging, could help solve the problem of knowing how fresh a food really is. In addition, this technology could be used to determine if medications and other perishable products are still active or fresh. The tags, which are about the size of a kernel of corn, would appear in various color codes on packaging.

“In our configuration, red, or reddish orange, would mean fresh,” explained Zhang. “Over time, the tag changes its color to orange, yellow and later green, which indicates the food is spoiled.”

The colors signify a range between 100 percent fresh and 100 percent spoiled. For example, if the label listed the product should remain fresh for 14 days under refrigeration, but the tag is now orange, it would mean the product was only roughly half as fresh. In that case, the consumer would know the product is edible for only another seven days if kept refrigerated, according to Zhang.

Watermelon may help lower blood pressure

If you have high blood pressure, you may want to consider eating more watermelon. It turns out that substances found in watermelon help lower blood pressure. Researchers at Florida State University conducted a study and found that watermelon could significantly reduce blood pressure in overweight individuals both at rest and while under stress.

The study started with a simple concept. More people die of heart attacks in cold weather because of the stress of the cold temperatures. The stress from the cold causes blood pressure to increase and the heart has to work harder to pump blood into the aorta. Adults with obesity and high blood pressure face a higher risk for stroke or heart attack when exposed to the cold either during the winter or in rooms with low temperatures.

So, what might help their hearts? It turned out that watermelon may be part of the answer, according to the Florida researchers.

They conducted a study with 13 middle-aged, obese men and women who also suffered from high blood pressure. To simulate cold weather conditions, one hand of the subject was dipped into 39 degree water (4 degrees Celsius) while the researchers took their blood pressure and other vital measurements. The group was divided into two. For the first six weeks, one group was given four grams of watermelon extract. The other group was given a placebo for six weeks. Then, they switched for the second six weeks.

Participants also had to refrain from taking any blood pressure medications or making any significant changes in their lifestyle during the study. The results showed that consuming watermelon had a positive impact on aortic blood pressure and other vascular parameters. All the volunteers showed improvements in blood pressure and cardiac stress while both at rest and while they were exposed to the cold water.

Study suggests mammograms offer limited benefit to oldest female patients

Doctors should focus on life expectancy when deciding whether to order mammograms for their oldest female patients, according to a new study. Researchers found that the harms of screening likely outweigh the benefits unless women are expected to live at least another decade.

National guidelines recommend that doctors make individualized screening decisions for women 75 and older. But a new analysis has concluded that since this age group was not included in mammography trials, there is no evidence that screening helps them live longer, healthier lives.

The authors of the study report that many women in this age group receive regular mammograms anyway, with no discussion about the uncertain benefit or potential harms of continued testing. They concluded that women who are expected to live a decade or more should talk with their doctors and weigh the potential benefits of diagnosing a dangerous but treatable cancer through mammography against the possibility of being misdiagnosed or treated aggressively for a cancer that posed no real harm.

“People should be informed that everything we do in medicine can have good and bad effects and that goes for mammography,” said Dr. Louise Walter, who is with the University of California San Francisco, San Francisco, California.

John Schieszer is an award-winning national journalist and radio broadcaster of The Medical Minute. He can be reached at

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John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute.

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