Cooking with Gas

The Republican-controlled House approved bills that protect gas stoves from overzealous government regulators. One bill would prohibit use of federal money to regulate gas stoves as a hazardous product; a separate measure would block an Energy Department rule setting stricter energy efficiency standards for stovetops and ovens.

Neither bill is expected to advance in the Senate, and the Biden administration does not support any attempt to ban the use of gas stoves.

Cooking with gas (from flamingoappliance.com/oven-repair/gas-stove-maintenance-tips/).

Welcome back. What is going on with gas stoves? Permit me to skip the politics and jump to the science. To help explain the issue I’ll review a recent study of the carcinogen benzene by researchers affiliated with Stanford University, PSE Healthy Energy, University of California, Berkeley and Lawrence Berkely National Lab.

Natural Gas Emissions
Natural gas appliances emit carbon dioxide through combustion and methane through leaks and incomplete combustion. Methane, the principal component of natural gas, is second only to carbon dioxide as a greenhouse gas contributor to global climate change. Home gas appliances also release health-damaging air pollutants, though only stoves typically release these pollutants into home air rather than through outdoor vents.

Some 47 million U.S. households cook with gas. A recent population-level analysis concluded that approximately 12% of childhood asthma in the U.S. is attributable to gas stoves.

Benzene
Benzene, a chemical linked to a higher risk of leukemia and other blood cell cancers, forms in flames and other high-temperature environments, such as oil field and refinery gas flares. Unfortunately, benzene also forms in gas stove flames.

The researchers sampled 87 stoves in 14 California and Colorado counties between January and December 2022. Sampled residences included kitchens in homes, apartments and Airbnb rentals. They calculated benzene emission rates attributable to gas combustion by measuring the increase in benzene concentration over time in sealed and unsealed kitchens, sometimes testing more than one burner or oven separately.

They also measured benzene concentrations in kitchens and bedrooms for various stove-use scenarios, such as cooking a meal on a gas range. In six houses, they measured 8-hour time course concentrations in open kitchens, without using fans or other active air circulation means. Ovens were set to 475 °F for 1.5 hours, and after turning off the oven, benzene concentrations were monitored for 6.5 more hours in the bedroom farthest from the kitchen.

Benzene Sampling Results
Benzene emissions from gas and propane burners and ovens were substantial, much higher than electric modes, and repeatable for replicates of gas ovens at 350 °F and gas burners set on high up to three months apart. In a subset of the sample, a single gas burner or oven raised kitchen benzene concentrations above the upper range of indoor benzene concentrations attributable to secondhand tobacco smoke.

Benzene emission rates (micrograms/minute) per stove type and setting (Table 2, from pubs.acs.org/doi/10.1021/acs.est.2c09289).

In all six cases of ambient benzene in bedrooms farthest from open kitchens’ burner or oven use, the elevated peak bedroom benzene concentrations were 5 to 70 times above baseline levels. In some cases, they exceeded the California Office of Environmental Health Hazard Assessment acute and chronic Reference Exposure Levels.

Wrap Up
The study findings suggest that concentrations of benzene produced by gas and propane combustion in stoves and ovens may increase health risks, especially if the hood is not used regularly and vented to the outside.

The results also suggest that the EPA significantly underestimates benzene emissions from residential gas combustion. Though the quantity of benzene attributable to stoves and ovens is small, it could have a disproportionate effect on health because the benzene is emitted directly indoors.

The researchers emphasize that further research is needed to assess actual exposures and the full health impacts. In the meantime, it’s your call regarding overzealous government regulators and stricter energy efficiency standards for stovetops and ovens. Thanks for stopping by.

P.S.
House bills to protect gas stoves: apnews.com/article/gas-stoves-ban-biden-energy-climate-regulation-d70577c96570cffd8bec84129b2c1a29
Benzene public health statement: www.atsdr.cdc.gov/ToxProfiles/tp3-c1-b.pdf
Study of U.S. gas stoves and childhood asthma in Inter. Jour. of Environmental Research and Public Health: www.mdpi.com/1660-4601/20/1/75
Study of benzene from stove gas and propane combustion in Environmental Science & Technology journal: pubs.acs.org/doi/10.1021/acs.est.2c09289
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/992631

Salt in Mind

Welcome back. Some time ago, Vicki and I visited an art museum and dined in its very nice café. Our selected dishes were preceded by pieces of special bread, which Vicki enjoyed but I found too salty.  

Salt (sodium chloride)
on a saucer.

My distaste for salt is probably due to my mother’s judicious use of the mineral. An exceptional cook, she leaned toward undersalting having once oversalted the entrée she prepared when hosting a guest of my father.

Or maybe my dislike arose grabbing a bite to eat with friends during high school or when we were all back in town. My salt taste buds joined the witness protection program watching the guys reach for the salt shaker before tasting the already salty pizza, hamburger, hotdog or other fine-dining fare.

Of course, nowadays, with the concern about salt and high blood pressure, I’m grateful that I was never big on salt. And woe is us, there’s always research with a new concern about salt. Before I discuss one such study, I’d better review the latest guidelines to be sure we’re dining at the same table.

Healthy Level of Sodium
The Dietary Guidelines for Americans 2015-2020 recommends that adults and children ages 14 years and older limit sodium, which is primarily consumed as salt (sodium chloride), to less than 2300 milligrams (mg) per day. That’s about 1000 mg/day less than our current average consumption, yet it’s the highest level likely to pose no health risk to almost everyone.

The recommendation is based on evidence of a relationship between increased sodium intake and increased blood pressure. While there’s also evidence of an association between sodium intake and cardiovascular disease, that evidence is not as consistent as the evidence on blood pressure, a surrogate indicator of cardiovascular disease.

Salt and Dementia
OK, the new concern about salt? Weill Cornell Medicine researchers linked a diet rich in salt to an increased risk of dementia and cerebrovascular (brain and its blood vessels) diseases.

If it makes you feel any better, the work reported thus far was limited to mice. Mice were fed food with 4% and 8% salt, the latter being comparable to the high end of human consumption. After eight weeks, magnetic resonance imaging of the mice showed significantly lower resting cerebral blood flow in the cortex and hippocampus, areas of the brain involved in learning and memory.

The researchers also found the excess salt suppressed functioning of cells lining blood vessels to the brain (endothelial cells). This caused a reduction of nitric oxide, a gas the cells produce to relax the blood vessels and increase blood flow.

After some mice were put back on their regular diet for four weeks, their cerebral blood flow and blood vessel cell function returned to normal. But mice that continued on the high salt diet developed dementia as measured by different criteria (object recognition test, maze test and nest building).

The researchers performed additional experiments toward understanding the biological mechanisms linking high salt intake with dementia and preventing the suppression of nitric oxide, and work continues.

Wrap Up
I could relax if reducing sodium was as simple as not reaching for the salt shaker. Unfortunately, most of the sodium we eat comes from packaged, processed, store-bought and restaurant foods. A study of 450 adults from three U.S. metropolitan areas, for example, found sodium in processed and restaurant foods accounted for 71% of the participants’ sodium intake! Only 11% was added at home, either in cooking or at the table.

If you compare nutrition labels, such as the two cold cereals shown here, be sure to take the serving size (at top) into account.

There’s some evidence that potassium intake can help balance the effects of sodium; however, overall diet, lifestyle and exercise are likely to be more important. One appendix in the Dietary Guidelines report is devoted to physical activity recommendations.

So, join me in reading the labels. As we cut back on sugar, let’s try to do the same with sodium. And thanks for stopping by.

P.S.
Example articles on health risks related to salt and sodium: www.hsph.harvard.edu/nutritionsource/salt-and-sodium/sodium-health-risks-and-disease/
en.wikipedia.org/wiki/Health_effects_of_salt
Sodium recommendations in Dietary Guidelines for Americans 2015-2020 8th Edition: health.gov/dietaryguidelines/2015/guidelines/chapter-1/a-closer-look-inside-healthy-eating-patterns/#other-components
Study linking salt to dementia in Nature Neuroscience journal: www.nature.com/articles/s41593-017-0059-z
Article on study on ScienceDaily website: www.sciencedaily.com/releases/2018/01/180116131306.htm
Study on sources of sodium in U.S. diet in Circulation journal: circ.ahajournals.org/content/135/19/1775
Example article on potassium and health (also see first article cited above): www.heart.org/HEARTORG/Conditions/HighBloodPressure/MakeChangesThatMatter/How-Potassium-Can-Help-Control-High-Blood-Pressure_UCM_303243_Article.jsp#.WmyesjdryUk

A version of this blog post appeared earlier on www.warrensnotice.com.

Cookbook Food Safety

Welcome back. Nearly two years ago, I reviewed a study that found chefs on television cooking shows either ignored food safety or demonstrated very limited positive behaviors. If viewers adopted the chefs’ practices, there could be a rash of foodborne illnesses (Careless Cooking).

Bad as that is, the Berkeley Wellness Letter pointed me to a more recent food safety study that I find more personally alarming. This one is about cookbook recipes. Though there’s no chance that I would watch a TV cooking show, I might buy a cookbook--oh, not for me; as a gift. Well, I might have if I hadn’t seen this study.

How could I go wrong following
recipes in the cookbook my mother
gave me when I was in college?

Recipe Analysis for Food Safety
Researchers from North Carolina State University and the US Department of Agriculture reviewed 1,497 recipes from 29 cookbooks that were popular enough to be on the New York Times food and diet best sellers list in 2013 and 2014.

Unlike the TV chef study, which flagged chefs’ behaviors against a checklist of 20 food safety practices, the cookbook study was much more selective. The researchers only considered recipes that contained raw animal ingredients (meat, poultry, seafood or eggs), whose dishes could effectively be measured with a digital thermometer.

They evaluated the recipes for guidance related to (1) the endpoint temperatures of what’s being cooked and (2) avoiding cross-contamination, the potentially harmful effects of inadvertently transferring microorganisms from one substance or object to another (e.g., raw food to ready-to-eat food).

Most Recipes Fail at Food Safety
In assessing endpoint temperatures, the concern was if the recipe stated to cook the dish to a specific internal temperature and if that specified temperature was indeed safe. (See www.foodsafety.gov/keep/charts/mintemp.html for safe minimum cooking temperatures.)

Of the nearly 1,500 recipes, only 123 (8%) mentioned cooking the dish to a specific temperature. Of those, 89 (6%) gave accurate information regarding endpoint temperatures, while 34 (2%) gave temperatures too low to kill the most likely food pathogens.

In lieu of or in addition to temperature, nearly all of the recipes offered subjective and risky recommendations of when the dishes would be done cooking, most commonly noting time, color and texture. None of these indicators could be relied on to determine if the dish had actually reached a safe temperature, though presumably all were more informative than “cook until done.”

Guidance on avoiding cross contamination was largely absent from the recipes. For example, only 12 recommended washing hands after touching raw animal protein, and only 29 recommended that raw and cooked foods be kept separate by using different or clean cutting boards, utensils and dishes. Worse, some recipes recommended that raw poultry be washed before cooking. That’s a no-no, since washing risks spreading harmful bacteria through splatter or aerosolization. 

OK, so maybe the “wash bird inside and outside” needs
updating, but at least I learned to first remove the feathers
and cut off the head.

Wrap Up
TV cooking shows forego the opportunity to demonstrate or discuss food safety; they fail to promote the idea that good food and safe food are inseparable.

Cookbook authors have, but are failing to take advantage of, that same opportunity. Including food safety guidance in cookbooks could go a long way toward reducing the risk of foodborne illness, which affects about 1 in 6 Americans each year.

Thanks for stopping by, and as I wrote in that earlier blog post, Bon appétit.

P.S.
Research study on evaluating cookbook food safety in British Food Journal: www.emeraldinsight.com/doi/full/10.1108/BFJ-02-2017-0066
News release on the study from North Carolina State University: news.ncsu.edu/2017/03/cookbooks-food-safety-2017/
University of California, Berkeley Wellness Letter, Nov 2017, “My cookbook made me sick.” pg 6.
The Charlotte Observer article on inclusion of Gwyneth Paltrow’s cookbook in the study: www.charlotteobserver.com/living/food-drink/article142547159.html

A version of this blog post appeared earlier on www.warrensnotice.com.

Careless Cooking

Welcome back. Now that you’re here, how should I begin? I could point out that I’m big on hygiene, as evidenced by multiple blog posts (see Blog Post Topics on right of website). Or I could just say that I’m not big on cooking. Unlike my wife, Vicki, and our son, Noah, I have zero interest in cooking. (Noah telephoned once, excited that he’d prepared a red velvet cake. I was happy for his cooking success, though I neither knew nor cared what a red velvet cake was.)
 
These thoughts about hygiene and cooking rushed to mind when I came across a study on television cooking shows and celebrity chef food safety. 

TV Cooking Shows

Philip Harben, the first TV cooking show
chef; began 1946, BBC. (Photo from
BBC Genome Blog)

Before I jump into the study, I should note that only 1 in 5 American adults are like me and never watch TV cooking shows, which is to say 4 in 5 adults do watch the shows, even if rarely. (These statistics are from a 2010 survey, but since the number and availability of the shows have increased, I’ll assume the statistics are still reasonable.)

One more statistic. About 1 in 6 Americans experience foodborne illnesses each year. Television is one of the many sources that provide or could provide information on how they could be prevented.

Celebrity Chef Food Safety
To evaluate food safety behaviors conveyed by television cooking shows, researchers from Kansas State and Tennessee State universities watched 100 episodes of 24 different celebrity chefs preparing meat dishes. They chose the shows randomly from cable or online services (e.g., Hulu, Netflix or Amazon) and evaluated each episode using a checklist they developed based on expert food safety knowledge and prior studies.

Their checklist had some 20 food safety practices categorized after the Fight Bac! Program: “Clean,” wash hands and surfaces often; “Separate,” don’t cross-contaminate; “Cook” to safe temperatures; and “Chill,” refrigerate promptly.

Celebrity Chef Behaviors

Dione Lucas, the first female TV
cooking show chef; began 1947,
New York City station.(Photo
from CQUnivNews Archive)

The researchers discovered that the TV chefs either ignored food safety or demonstrated very limited positive behaviors. If viewers adopted the chefs’ practices, there could be a rash of foodborne illnesses.

Some of the most commonly observed poor behaviors were that 88% of the chefs did not wash their hands after handling uncooked meat (or were not shown washing or mentioning handwashing); 79% added food with their hands; 50% ate while cooking; 75% did not use a thermometer to determine if the meat was ready; and 25% used the same cutting board to prepare ready-to-eat items and uncooked meat.

The behavior that won my Oh, come on! prize was that 21% of the chefs licked their fingers while cooking. The same number touched their hair, but that would have slipped by me.

Wrap Up
The study was intended to highlight the problem with food television culture, not shame the celebrity chefs. The chefs may have sterling food safety behaviors when off-camera, or perhaps their good practices were edited out of the shows for time or entertainment. What was broadcast, however, was poor food safety behaviors, which viewers might mistakenly believe are acceptable.

Cooking shows and celebrity chefs are popular with TV viewers. Instead of taking the opportunity to demonstrate or discuss good food safety--to promote the idea that good food and safe food are inseparable--the shows too often promote the opposite behavior.

Thanks for stopping by. Bon appétit.

P.S.
Celebrity chef food safety study in Journal of Public Health: jpubhealth.oxfordjournals.org/content/early/2016/04/18/pubmed.fdw026.full
Article on celebrity chef study on Science Daily website:
www.sciencedaily.com/releases/2016/12/161214100737.htm
Harris Poll statistics on TV cooking show viewers: www.marketingcharts.com/television/8-in-10-us-adults-watch-cooking-shows-13719/
Fight Bac! Program’s clean, separate, cook, chill: www.fightbac.org/wp-content/uploads/2015/08/Basic_Fight_BAC_Brochure_Oct_2011.pdf
The first TV chefs: www.history.com/news/hungry-history/lights-camera-action-the-first-tv-chefs