For home cooks, widespread techniques for judging doneness of chicken may not ensure that pathogens are reduced to safe levels. Solveig Langsrud of the Norwegian Institute of Food, Fisheries and Aquaculture Research and colleagues present these findings in the open-access journal PLOS ONE on April 29, 2020.

Chicken can harbor the bacterial pathogens Salmonella and Campylobacter. High temperatures can kill these microbes, but enough may survive to cause illness if meat is undercooked. Recommendations for monitoring doneness vary widely, and the prevalence and safety of methods commonly used by home cooks have been unclear.

To help clarify consumers' chicken cooking practices, Lansgrud and colleagues surveyed 3,969 private households across five European countries (France, Norway, Portugal, Romania, and the U.K.) on their personal chicken cooking practices. They also interviewed and observed chicken cooking practices in 75 additional households in the same countries.

The analysis indicated that checking the inner color of chicken meat is a popular way to judge doneness, used by half of households. Other common methods include examining meat texture or juice color. However, the researchers also conducted laboratory experiments to test various techniques for judging doneness, and these demonstrated that color and texture are not reliable indicators of safety on their own: for example, the inner color of chicken changes at a temperature too low to sufficiently inactivate pathogens.

 

Food safety messages often recommend use of thermometers to judge doneness, but the researchers found that the surface of chicken meat may still harbor live pathogens after the inside is cooked sufficiently. Furthermore, thermometers are not widely used; only one of the 75 observed households employed one.

 

These findings suggest a need for updated recommendations that guarantee safety while accounting for consumers' habits and desire to avoid overcooked chicken. For now, the researchers recommend focusing on the color and texture of the thickest part of the meat, as well as ensuring that all surfaces reach sufficient temperatures.

 

"Consumers are often advised to use a food thermometer or check that the juices run clear to make sure that the chicken is cooked safely -- we were surprised to find that these recommendations are not safe, not based on scientific evidence and rarely used by consumers," adds Dr Langsrud. "Primarily, consumers should check that all surfaces of the meat are cooked, as most bacteria are present on the surface. Secondly, they should check the core. When the core meat is fibrous and not glossy, it has reached a safe temperature.

 

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As scientists scramble to learn more about the SARS-CoV-2 coronavirus, two recent studies of the virus' genome reached controversial conclusions: namely, that snakes are intermediate hosts of the new virus, and that a key coronavirus protein shares "uncanny similarities" with an HIV-1 protein. Now, a study in ACS' Journal of Proteome Research refutes both ideas and suggests that scaly, anteater-like animals called pangolins are the missing link for SARS-CoV-2 transmission between bats and humans.

Understanding where SARS-CoV-2 -- the virus that caused the COVID-19 pandemic -- came from and how it spreads is important for its control and treatment. Most experts agree that bats are a natural reservoir of SARS-CoV-2, but an intermediate host was needed for it to jump from bats to humans.

A recent study that analyzed the new virus' genome suggested snakes as this host, despite the fact that coronaviruses are only known to infect mammals and birds. Meanwhile, an unrelated study compared the sequence of the spike protein -- a key protein responsible for getting the virus into mammalian cells -- of the new coronavirus to that of HIV-1, noting unexpected similarities. Although the authors withdrew this preprint manuscript after scientific criticism, it spawned rumors and conspiracy theories that the new coronavirus could have been engineered in a lab. Yang Zhang and colleagues wanted to conduct a more careful and complete analysis of SARS-CoV-2 DNA and protein sequences to resolve these issues.

Compared to the previous studies, the researchers used larger data sets and newer, more accurate bioinformatics methods and databases to analyze the SARS-CoV-2 genome. They found that, in contrast to the claim that four regions of the spike protein were uniquely shared between SARS-CoV-2 and HIV-1, the four sequence segments could be found in other viruses, including bat coronavirus.

After uncovering an error in the analysis that suggested snakes as an intermediate host, the team searched DNA and protein sequences isolated from pangolin tissues for ones similar to SARS-CoV-2. The researchers identified protein sequences in sick animals' lungs that were 91% identical to the human virus' proteins. Moreover, the receptor binding domain of the spike protein from the pangolin coronavirus had only five amino acid differences from SARS-CoV-2, compared with 19 differences between the human and bat viral proteins. This evidence points to the pangolin as the most likely intermediate host for the new coronavirus, but additional intermediate hosts could be possible, the researchers say.

The authors acknowledge funding from the National Science Foundation, the National Institute of General Medical Sciences, the National Institute of Allergy and Infectious Diseases and the Extreme Science and Engineering Discovery Environment.

When should you eat to manage your weight? Breakfast, not late-night snacks

The balance between weight gain and weight gain loss is predominantly determined by what you eat, how much you eat, and by how much exercise you get. But another important factor is often neglected... it's not just how many calories you eat, but WHEN you eat them that will determine how well you burn those calories.

  

The balance between weight gain and weight gain loss is predominantly determined by what you eat, how much you eat, and by how much exercise you get. But another important factor is often neglected... Published February 27 in the open-access journal PLOS Biology, research conducted by Kevin Kelly, Owen McGuinness, Carl Johnson and colleagues of Vanderbilt University, USA shows that it's not just how many calories you eat, but WHEN you eat them that will determine how well you burn those calories.

Your daily biological clock and sleep regulate how the food you eat is metabolized; thus the choice of burning fats or carbohydrates changes depending on the time of day or night. Your body's circadian rhythm has programmed your body to burn fat when you sleep, so when you skip breakfast and then snack at night you delay burning the fat.

The researchers monitored the metabolism of mid-aged and older subjects in a whole-room respiratory chamber over two separate 56-hour sessions, using a "random crossover" experimental design. In each session, lunch and dinner were presented at the same times (12:30 and 17:45, respectively), but the timing of the third meal differed between the two halves of the study. Thus in one of the 56-hour bouts, the additional daily meal was presented as breakfast (8:00) whereas in the other session, a nutritionally equivalent meal was presented to the same subjects as a late-evening snack (22:00). The duration of the overnight fast was the same for both sessions.

Whereas the two sessions did not differ in the amount or type of food eaten or in the subjects' activity levels, the daily timing of nutrient availability, coupled with clock/sleep control of metabolism, flipped a switch in the subjects' fat/carbohydrate preference such that the late-evening snack session resulted in less fat burned when compared to the breakfast session. The timing of meals during the day/night cycle therefore affects the extent to which ingested food is used versus stored.

This study has important implications for eating habits, suggesting that a daily fast between the evening meal and breakfast will optimize weight management.

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HOW TO GET CHILDREN TO EAT VEGETABLES? BOTH PARENTS SET AN EXAMPLE!

A positive example set by both the mother and the father promotes the consumption of vegetables, fruit and berries among 3-5-year-old children, according to a new study from the University of Eastern Finland. The study explored the association of the home food environment and parental influence with the consumption of vegetables among kindergarten-aged children. The findings were published in Food Quality and Preference.

Children eat inadequate amounts of vegetables, fruit and berries across Europe and elsewhere, too. As the health and nutrition benefits of these foods are well-known, increasing their consumption among children is a challenge many countries are struggling with. Dietary habits also track from childhood to adulthood, and the period of early childhood is critical for adapting to a diet rich in greens.

The researchers studied the consumption of vegetables, fruit and berries, and the family's home food environment, through a survey taken by parents. The study looked at 114 kindergarten-aged children and their parents (100) in Finland. Raw and cooked vegetables and fruit and berries were analysed separately.

The researchers found that to a certain degree, the consumption of vegetables is affected by different factors than the consumption of fruit and berries. Maternal example was associated with the consumption of raw and cooked vegetables as well as with the consumption of fruit and berries. Paternal example, on the other hand, was the strongest for cooked vegetables.

"This shows that teaching children to eat their greens is not something mothers should be doing alone. A positive example set by both parents is important, as is their encouragement of the child," Researcher and Nutritionist Kaisa Kähkönen from the University of Eastern Finland says.

The study also showed that dinner is the most important meal at home when it comes to teaching children to eat vegetables. The families participating in the study often ate dinner together, highlighting the role of parental influence on the development of children's dietary choices and preferences.

Dinner constitutes a daily opportunity to serve vegetables in a variety of different forms: as the main course, as a side dish, and as salad.

"Variation can be created by serving raw vegetables, such as the ever-popular cucumber and tomato, accompanied by cooked ones. In fact, many root vegetables, cabbages and squashes are best served cooked," Kähkönen says.

When it comes to eating fruit, evening snacks were the most important meal.

The study shows that many families still eat less vegetables, fruit and berries on average than would be beneficial in view of health promotion. Cooked vegetables and berries were the least eaten food items among the study population.

The Institute of Public Health and Clinical Nutrition at the University of Eastern Finland studies how food education in early childhood can support good nutrition among children and promote the establishment of healthy dietary habits.

The newly published study was carried out in collaboration between researchers from the Universities of Eastern Finland, Jyväskylä and Turku. The study was funded by the Jenny and Antti Wihuri Fund.

US households Waste Nearly a third of the Food They Acquire

American households waste, on average, almost a third of the food they acquire, according to economists, who say this wasted food has an estimated aggregate value of $240 billion annually. Divided among the nearly 128.6 million U.S. households, this waste could be costing the average household about $1,866 per year.

This inefficiency in the food economy has implications for health, food security, food marketing and climate change, noted Edward Jaenicke, professor of agricultural economics, College of Agricultural Sciences, Penn State.

"Our findings are consistent with previous studies, which have shown that 30% to 40% of the total food supply in the United States goes uneaten -- and that means that resources used to produce the uneaten food, including land, energy, water and labor, are wasted as well," Jaenicke said. "But this study is the first to identify and analyze the level of food waste for individual households, which has been nearly impossible to estimate because comprehensive, current data on uneaten food at the household level do not exist."

The researchers overcame this limitation by borrowing methodology from the fields of production economics -- which models the production function of transforming inputs into outputs -- and nutritional science, by which a person's height, weight, gender and age can be used to calculate metabolic energy requirements to maintain body weight.

In this novel approach, Jaenicke and Yang Yu, doctoral candidate in agricultural, environmental and regional economics, analyzed data primarily from 4,000 households that participated in the U.S. Department of Agriculture's National Household Food Acquisition and Purchase Survey, known as FoodAPS. Food-acquisition data from this survey were treated as the "input."

FoodAPS also collected biological measures of participants, enabling the researchers to apply formulas from nutritional science to determine basal metabolic rates and calculate the energy required for household members to maintain body weight, which is the "output." The difference between the amount of food acquired and the amount needed to maintain body weight represents the production inefficiency in the model, which translates to uneaten, and therefore wasted, food.

"Based on our estimation, the average American household wastes 31.9% of the food it acquires," Jaenicke said. "More than two-thirds of households in our study have food-waste estimates of between 20% and 50%. However, even the least wasteful household wastes 8.7% of the food it acquires."

In addition, demographic data collected as part of the survey were used to analyze the differences in food waste among households with a variety of characteristics.

For example, households with higher income generate more waste, and those with healthier diets that include more perishable fruits and vegetables also waste more food, according to the researchers, who reported their findings in the American Journal of Agricultural Economics.

"It's possible that programs encouraging healthy diets may unintentionally lead to more waste," Jaenicke said. "That may be something to think about from a policy perspective -- how can we fine-tune these programs to reduce potential waste."

Household types associated with less food waste include those with greater food insecurity -- especially those that participate in the federal SNAP food assistance program, previously known as "food stamps" -- as well as those households with a larger number of members.

"People in larger households have more meal-management options," Jaenicke explained. "More people means leftover food is more likely to be eaten."

In addition, some grocery items are sold in sizes that may influence waste, he said.

"A household of two may not eat an entire head of cauliflower, so some could be wasted, whereas a larger household is more likely to eat all of it, perhaps at a single meal."

Among other households with lower levels of waste are those who use a shopping list when visiting the supermarket and those who must travel farther to reach their primary grocery store.

"This suggests that planning and food management are factors that influence the amount of wasted food," Jaenicke said.

Beyond the economic and nutritional implications, reducing food waste could be a factor in minimizing the effects of climate change. Previous studies have shown that throughout its life cycle, discarded food is a major source of greenhouse gas emissions, the researchers pointed out.

"According to the U.N. Food and Agriculture Organization, food waste is responsible for about 3.3 gigatons of greenhouse gas annually, which would be, if regarded as a country, the third-largest emitter of carbon after the U.S. and China," Jaenicke said.

The researchers suggested that this study can help fill the need for comprehensive food-waste estimates at the household level that can be generalized to a wide range of household groups.

"While the precise measurement of food waste is important, it may be equally important to investigate further how household-specific factors influence how much food is wasted," said Jaenicke. "We hope our methodology provides a new lens through which to analyze individual household food waste."

The U.S. Department of Agriculture's National Institute of Food and Agriculture supported this work through its Agriculture and Food Research Initiative.