It’s all in the friction: Hand dryers are germ-flinging BS

The benefits of paper towels versos conventional blow dryers for drying after handwashing are well-documented.

handwash_south_park(2)But what about those high-tech – and expensive – Dyson thingies that seem to be popping up everywhere.

I say, show me the data.

Caroline Weinberg writes that a study published in the Journal of Applied Microbiology showed that Dyson jet air dryers can fling germs as far as 10 feet from the device.

For the experiment, researchers dipped their gloved hands in a suspension of the bacteriophage MS2 (similar in structure to the contagious enteric viruses transmitted in poop). The hands were then dried by one of three methods. First up were Dyson jet air dryers, which are designed to push water off of your hands in 10 seconds with roughly the force of a jet engine. Next were warm air dryers, which blow warm air downwards and supposedly remove water via evaporation. The final competitor was paper towels, which use absorbent paper to remove water from your hands (and actually leave them dry).

The first part of the experiment looked at how many bacteria are blown back on you during the drying process. Researchers erected a vertical board roughly 16 inches away from each dryer and counted the viral particles that landed on it. Overall, the jet dryer dispersed 60 times more particles than the warm air dryer and 1,300 more than the paper towel. 70 percent of particles hit the board between 2.5 and 4.5 feet—roughly chest or stomach level on an woman of average height, or right at the face level of a small child. At the highest density point, the jet air dryer dispersed 167 times as many viral particles as the warm air dryer and 8,340 times as many as a paper towel.

dyson.air-blade-thumb-468x369-147704For the second part of the experiment, researchers studied air dispersal, or how much of the bacteria is spread into the air around the machine or towel. Airborne virus counts were consistently higher around the jet dryer both over time and distance. The jet dryer dryer propelled the virus as far as 10 feet away, with high levels recorded a full 15 minutes after use. There was no significant difference in air dispersal between warm air dryers and paper towels.

This isn’t a perfect study: Because it was done in a lab setting, researchers could not account for individual behaviors or real world differences. They also only tested one example of each hand drying device (Dyson is taking the heat here, but they are not the only makers of jet air dryers) and did so over a small number of trials. Critics of the study also rightfully point out that most people don’t dip their hands in bacteria prior to using the hand dryers: they wash their hands first. And it’s true that if one were to stick perfectly clean hands into a dryer, there would not be germs to blow around.

Unfortunately, here in the real world, 95% of people using public restrooms fail to adequately wash their hands. Sure, a small percentage may use the scientifically vetted, 42-second-long, six-step hand washing process that most effectively rids your hands of all the filthy germs you’ve picked up in the bathroom and world at large. The rest of them (OK, us) are doing a quick scrub or, worse, simply passing their hands under a running faucet for a few seconds for the illusion of cleanliness. So while the hands most people place in the dryer aren’t drenched in germs, they are likely carrying, among other things, poop particles. Poop particles that the machine then proceeds to blow all over the room, including back on the very hands you just cleaned.

handwashing.blow.dryer.09This isn’t the first time a study has suggested that hand dryers are germ cannons, either. A 2014 study published in the Journal of Hospital Infection also supports this finding—but it was dismissed by Dyson as funded by Big Paper Towel (in their defense, that study was literally funded by Big Paper Towel, i.e. the European Tissue Symposium,). Dyson would direct us, instead, to 2011 study published in the Journal of Applied Microbiology that found their air dryers to be more effective at preventing the spread of germs than warm air dryers. Now it was Big Paper Towel’s turn to cry foul—that study was funded by Dyson Limited. The current study in question is funded independently by the researchers’ university (though the lead author has worked with the European Tissue Symposium in the past) lending it a hopefully uncontaminated air of legitimacy.

A few months ago, shortly after this study was published, Dyson posted an ominously narrated attack ad of sorts titled “Paper’s Dirty Secret.” Don’t listen to Big Jet Dryer’s propaganda (well, maybe listen to it, because the video is hilarious—but don’t believe it). It is true that a 2012 pilot study found unused paper towels to be contaminated with small amounts of bacteria. But paper towels have been repeatedly shown to be efficient, effective, and—perhaps most importantly—not responsible for flinging extra poop germs through the air.

 

Food Safety Talk 99: Are you familiar with the Haugh Unit?

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University.  Every two weeks or so, Ben and Don get together virtually and talk for about an hour.

They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. mm_Haugh_Tester-albumen

Episode 99 can be found here and on iTunes.

Don and Ben talk pickles, puppies, Lord Stanley and his cup, the Internet, eggs, coffee, deli slicers and cuisine from around the world. After Dark turns into taxes safety talk.

Below are some links to some of the things that they talked about:

Going public: 167 people with the runs in Iowa

That moment happened.

Usually it takes until puberty, but it happened.

diarrhea.toiletMy 7-year-old daughter, who was in a local Dettol commercial, which I had nothing to do with (that’s her, at the end, second row from the bottom, far rightin the pic below; I’ve always shamelessly promoted my children).

Yet this morning, she was too embarrassed to answer what number 1 meant, and number 2, while watching some other video this morning before school, something about poop.

And it happened.

Sure, kids find me hilarious until about 11-years-old, then it’s embarrassment for 10 years, then they come around.

Maybe the folks in Dubuque County, Iowa feel the same way, maybe they have state laws limiting what they can say.

But when 167 people have diarrhea since Oct 1, public health has to step in (not in the #2).

Seriously, no public announcement until April 11, 2011, on an outbreak that started Oct. 1, 2015?

 “This is a high number of diagnosed cases that we have had,” said Patrice Lambert, executive director of the Dubuque County Health Department.

Shigellosis is a disease caused by the bacterium shigella, which causes watery and sometimes bloody diarrhea, according to Lambert.

 “Wash your hands with soap and water,” Lambert said. “That’s the easiest thing to do, not only for shigellosis but for all communicable diseases.

Handwashing is never enough.

 

Medium and message: Need to frequently change handwashing signs to be effective

I’m a food safety voyeur.

Supermarkets, farmers markets, restaurants – fancy or not – kitchens, farms, I’ve been professionally watching people for 20 years.

surprise-01Chapman likes to recount how he was invited to the GFSI Consumer Goods Forum as a last minute replacement speaker in 2013 to talk about food safety infosheets and how we evaluated them.  He said that the literature shows surprise matters when it comes to communicating risks – and a message that is up all the time, like a hand washing sign, probably doesn’t do much after the day it was posted (when it is surprising to the food handler).

The level of surprise in a message determines how successfully the information is received. In 1948, the Bell Telephone Company commissioned a study on communication as a mathematical theory to aid in the design of telephones.  In a study of brain function, Zaghloul and colleagues (2009) also showed the brain’s sensitivity to unexpected or surprising information plays a fundamental role in the learning and adoption of new behaviors.

During the Q&A session at the end of the session someone from a German retail store asked Chapman if he was suggesting that that they take down all the handwashing posters they had up, and Chapman said, yes, unless they plan on changing them every couple of days. The audience had an audible gasp.

We’ve found that posting graphical, concise food safety stories in the back kitchens of restaurants can help reduce dangerous food safety practices and create a workplace culture that values safe food.

It was the first time that a communication intervention such as food safety information sheets had been validated to work using direct video observation in eight commercial restaurant kitchens and was published in the  Journal of Food Protection.

hand_sanitizer_hospital_11We found that infosheets decreased cross-contamination events by 20 per cent, and increased handwashing attempts by 7 per cent.

Based on observations of more than 5,000 patrons at a hospital-based cafeteria, we showed that an evidence-based informational poster can increase attempts at hand hygiene.

So we gladly welcome new work on food safety messages and media in poultry processing facilities.

Signs can provide repetitive training on specific food safety practices for multicultural food processing employees. Posted signs for workers in many food processing facilities tend to be text-heavy and focus specifically on occupational hazard safety. The purpose of this study was to evaluate the effectiveness of newly-developed hand washing pictograms on employees’ hand washing behavior using video observation.

Five employee hand washing behaviors (soap use, wash completeness, wash time, complete rinsing, and towel use) were evaluated with (a) no intervention, company signs posted and considered the baseline; and compared to (b) hand washing behavior the next day (short term) and two weeks (long term) after experimental hand washing signs were displayed at a raw poultry slaughter facility (Facility A) and a poultry further processing facility (Facility B).

sponge.bob.handwashingBoth facilities showed a significant increase (p < 0.05) in soap use after the new sign was introduced at both short and long term time periods. There was a significant increase (p < 0.05) in washing, time of washing, and rinsing observed by Facility B employees, when baseline data was compared to the short term. This indicates that a new sign could increase hand washing compliance at least in the short term. Sign color also had a significant effect (p < 0.05) on employee behavior for washing and time of washing. Behavior for four of the five variables (soap, wash, time of wash, and towel use) was significantly different (p < 0.05) between baseline and either experimental observation period.

While signs can be a useful tool to offer as recurring food safety training for food processing employees, employees tend to revert back to old habits after several weeks.

Evaluation of how different signs affect poultry processing employees’ hand washing practices

Food Control, Volume 68, October 2016, Pages 1–6

Matthew Schroeder, Lily Yang, Joseph Eifert, Renee Boyer, Melissa Chase, Sergio Nieto-Montenegro

http://www.sciencedirect.com/science/article/pii/S0956713516301244

 

Nebraska health board recommends no bare hands for restaurants

The No. 1 cause of what people often call food poisoning is not spoiled food. It is a flu-like illness called norovirus that comes with diarrhea and vomiting.

handwash_south_park(2)And the No. 1 cause of norovirus is people who have the virus on their hands touching food without gloves.

To help prevent outbreaks of the virus, a health-related advisory group to the Lincoln-Lancaster County Health Department has recommended the city tighten restaurant rules, seriously limiting when staff can touch ready-to-serve food with their bare hands.

The City Council likely will hold a public hearing on the no-bare-hands policy April 11. The Health Department advisory board approved it in early March. 

The idea behind the policy is that once food is cooked, no staffer should touch it before a customer eats it, said Scott Holmes, manager of the Environmental Health Division with the local health department. 

The proposed rule does allow some exceptions.

Staff can touch ready-to-eat food before it’s cooked, garnish beverages and wash fruits and vegetables with bare hands.

Some eating establishments already follow a no-bare-hands policy, including those that serve vulnerable or high-risk populations — people in custodial care, assisted-living facilities, hospitals, nursing homes and senior centers, for example.

And many chain restaurants already have such policies, Holmes said.

The local proposal follows a national model, with some exceptions. The committee that developed the Lincoln policy eliminated a few of the rules, ones that created the most controversy in other communities.

Food Safety Talk 95: What’s the right number of logs?

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University.  Every two weeks or so, Ben and Don get together virtually and talk for about an hour.

logs

They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. You can download the audio recordings right from the website, or subscribe using iTunes.

Episode 95 can be found here and on iTunes.

Show notes so you can follow along at home:

What are gloves protecting? The food or the handler?

This one time, in graduate school, a harvester told me that he loved wearing gloves when he picked tomatoes because it kept his hands from getting dirty.

Another time, in graduate school, a greenhouse manager told me he had convinced his boss that food safety was really important and the company invested in installing full restrooms in the greenhouse — and fully stocked a closet with latex gloves.

The manager trained all the employees on why clean hands and gloves were important.

A week after the training session he saw an employee urinating on the outside wall of the restroom.

With his gloves on.

Or maybe gloves are there to protect the food handlers from the food (thanks to Carl Custer for the cartoon).

Gloves-Baldo-2016-03-07

They said loads: reducing cross-contamination via hands

Hand washing and glove use are the main methods for reducing bacterial cross-contamination from hands to ready-to-eat food in a food service setting. However, bacterial transfer from hands to gloves is poorly understood, as is the effect of different durations of soap rubbing on bacterial reduction.

handwashing.loadsTo assess bacterial transfer from hands to gloves and to compare bacterial transfer rates to food after different soap washing times and glove use, participants’ hands were artificially contaminated with Enterobacter aerogenes B199A at ∼9 log CFU. Different soap rubbing times (0, 3, and 20 s), glove use, and tomato dicing activities followed. The bacterial counts in diced tomatoes and on participants’ hands and gloves were then analyzed.

Different soap rubbing times did not significantly change the amount of bacteria recovered from participants’ hands. Dicing tomatoes with bare hands after 20 s of soap rubbing transferred significantly less bacteria (P < 0.01) to tomatoes than did dicing with bare hands after 0 s of soap rubbing. Wearing gloves while dicing greatly reduced the incidence of contaminated tomato samples compared with dicing with bare hands. Increasing soap washing time decreased the incidence of bacteria recovered from outside glove surfaces (P < 0.05).

These results highlight that both glove use and adequate hand washing are necessary to reduce bacterial cross-contamination in food service environments.

Adequate hand washing and glove use are necessary to reduce cross-contamination from hands with high bacterial loads

Journal of Food Protection®, Number 2, February 2016, pp. 184-344, pp. 304-308(5)

Robinson, Andrew L.; Lee, Hyun Jung; Kwon, Junehee; Todd, Ewen; Rodriguez, Fernando Perez; Ryu, Dojin

http://www.ingentaconnect.com/content/iafp/jfp/2016/00000079/00000002/art00016

Barf train: Irish Rail forced to pull train from service throughout

During an outing on Monday, hundreds of members from two societies at Dublin City University boarded a train specifically chartered for them heading to Galway City.

vomit-6Those on-board were allowed to bring their own alcohol, and according to reports, there were only two security guards present to deal with the mass of students.

“The train was left in a dreadful state,” said a spokesperson for Irish Rail.

“The train was not able to enter service on Tuesday as it had to be deep cleaned on Tuesday and overnight on Wednesday before going back into service.”

According to the rail service vomit and “other fluids” where discovered throughout the train.

First reported in the College View, DCU’s student newspaper, the Engineering Society and Science & Health Society took 300 students from Dublin to Galway City on the train.

According to the newspaper, only two stalls were in working order during the journey, though a student on the train claimed “It was more like one.”

“We were locked in there with one toilet between 300 people,” said Josh, speaking to RTÉ’s Liveline.

“I don’t know what they expected. There was no where for anyone to get sick.”

Food Safety Talk 89: On a scale from 1 to 11

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University. Every two weeks or so, Ben and Don get together virtually and talk for about an hour. Spinal_Tap_-_Up_to_ElevenThey talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. You can download the audio recordings right from the website, or subscribe using iTunes.

Show notes and links so you can follow along at home: