Signs don’t work: Employees must wash hands

 Handwashing is important in preventing microbial cross-contamination. The US FDA Model Food Code requires that handwashing sinks have a sign or poster nearby that is visible to employees washing their hands.

jon.stewart.handwashing.2002This research collects and reviews existing handwashing signs and subjects them to quantitative analysis. An Internet search produced a database of handwashing signs. Lather time, rinse time, overall wash time, water temperature, water use, drying method, technique, and total number of steps were recorded.

Eighty-one unique handwashing signs were identified. Each sign had between one and thirteen steps. Thirty-seven signs indicated a specific lather time, with average time ~18 s. No sign suggested > 20 s lather, and none suggested < 10 s lather. Twenty-four signs recommended use of warm water. Two signs recommended 100°F (37.8°C) water and one recommended hot water. Sixty-two signs made a recommendation on drying hands, and fifty-three suggested using a paper towel.

Our analysis reveals that handwashing sign instructions can vary quite widely. Lack of consistent hand wash guidance on signage may contribute in part to a lack of handwashing consistency and compliance. Our study serves as a foundation for future research on handwash signage. 

Quantitative analysis of recommendations made in handwashing signs

Food Protection Trends, vol. 35, no. 4, pp. 270-279, July 2015

Dane A. Jensen, Donald W. Schaffner

http://www.foodprotection.org/publications/food-protection-trends/article-archive/2015-07quantitative-analysis-of-recommendations-made-in-handwashing-signs/

 

The hands have it: Food safety through handwashing

Handwashing is simple.

handwash_south_park(2)Science says otherwise.

Despite endless statements to just wash hands to be safe — in the kitchen, in food service, at the petting zoo —  little research has been done to quantify what actually works when it comes to handwashing.

U.S. government recommendations for 15-20 seconds of handwashing under vigorously flowing water after a potential contamination event may not be practical in a food service environment.

Dr. Donald Schaffner, a professor of food safety at Rutgers University, and colleagues, have attempted to add some science to the discussion.

“Many people seem to have strongly held opinions about handwashing, says Schaffner, “but the research base for those opinions is lacking. Our research begins to dispels some popular beliefs about handwashing.”

The researchers showed that even a minimal handwash (5 seconds, no soap) can remove about 90 per cent of bacteria on hands.

Further, the research showed that towel drying was much more effective than other methods because of the friction involved in physically removing bacteria from hands.

Schaffner says “Everyone has an opinion about handwashing, but our research is beginning to provide real data to help inform sensible policy.” 

 Contact: Dr. Donald Scaffner

schaffner@aesop.rutgers.edu

732-982-7475

Abstract

Quantifying the effect of hand wash duration, soap use, ground beef debris, and drying methods on the removal of Enterobacter aerogenes on hands

Journal of Food Protection®, Number 4, April 2015, pp. 636-858, pp. 685-690(6)

Jensen, Dane A.;Danyluk, Michelle D.; Harris, Linda J.;Schaffner, Donald W.

http://www.ingentaconnect.com/content/iafp/jfp/2015/00000078/00000004/art00007

Hand washing is recognized as a crucial step in preventing foodborne disease transmission by mitigating cross-contamination among hands, surfaces, and foods.

This research was undertaken to establish the importance of several keys factors (soap, soil, time, and drying method) in reducing microorganisms during hand washing. A nonpathogenic nalidixic acid–resistant Enterobacter aerogenes surrogate for Salmonella was used to assess the efficacy of using soap or no soap for 5 or 20 s on hands with or without ground beef debris and drying with paper towel or air. Each experiment consisted of 20 replicates, each from a different individual with ∼6 log CFU/ml E. aerogenes on their hands. A reduction of 1.0 ± 0.4 and 1.7 ± 0.8 log CFU of E. aerogenes was observed for a 5-s wash with no soap and a 20-s wash with soap, respectively. When there was no debris on the hands, there was no significant difference between washing with and without soap for 20 s (P > 0.05). Likewise, there was no significant difference in the reductions achieved when washing without soap, whether or not debris was on the hands (P > 0.05). A significantly greater reduction (P < 0.05) in E. aerogenes (0.5 log CFU greater reduction) was observed with soap when there was ground beef debris on the hands. The greatest difference (1.1 log CFU greater average reduction) in effectiveness occurred when ground beef debris was on the hands and a 20-s wash with water was compared with a 20-s wash with soap. Significantly greater (P < 0.05) reductions were observed with paper towel drying compared with air (0.5 log CFU greater reductions).

Used paper towels may contain high bacterial levels (>4.0 log CFU per towel) when hands are highly contaminated. Our results support future quantitative microbial risk assessments needed to effectively manage risks of foodborne illness in which food workers’ hands are a primary cause.

 Quantifying the effect of hand wash duration, soap use, ground beef debris, and drying methods on the removal of Enterobacter aerogenes on hands

01.apr.15

Journal of Food Protection®, Number 4, April 2015, pp. 636-858, pp. 685-690(6)

Jensen, Dane A.;Danyluk, Michelle D.; Harris, Linda J.;Schaffner, Donald W.

http://www.ingentaconnect.com/content/iafp/jfp/2015/00000078/00000004/art00007

handwash_infosht-2-7-08 copy (1)

New research or PR: Why paper towels are the most hygienic way to dry your hands?

I have no problem with who funds research, as long as there is full disclosure and the methodology is available for critique in a peer-reviewed journal. That would be the public part.

handwash_south_park(2)The Daily Mail in the UK thinks readers are too dumb to ask for references, and begins with, “Paper towels are the most hygienic way to dry hands after going to the loo, a study has found.”

It took The Mirror to note that the University of Westminster’s snappily-titled study ‘Comparison of different hand-drying methods: the potential for airborne microbe dispersal and contamination‘ was published in the March 2015 edition of The Journal of Hospital Infection.

The research was commissioned by paper towel manufacturers and claims that single-use towels are the most hygienic way to dry off.

It probably is.

The research also claims that bathroom air dryers may be blasting bacteria directly into the faces of children.

However, a major hand dryer manufacturer has disputed the claims, calling the research “flawed”.

The university’s study was undertaken by leading microbiologist Keith Redway of the University’s Department of Biomedical Sciences and looked at the potential for microbial contamination from hand drying and the potential risks for the spread of microbes in the air, particularly if hands are not washed properly.

jon.stewart.handwashing.2002The peer-reviewed research – which was commissioned by the European Tissue Symposium (ETS) – used four different hand drying methods and three different test models to compare differences between the drying methods and their capacity to spread microbes from the hands of users potentially to other people in public washrooms.

Paper towels, a textile roller towel, a warm air dryer and a jet air dryer were compared using three different test models: acid indicator using lemon juice, yeast, and bacterial transmission from hands when washed without soap.

The University of Westminster scientists found that the jet air dryer spread liquid from users’ hands further and over a greater distance – up to 1.5 m – than the other drying methods.

They also recorded the greatest spread of microbes into the air at both near and far distances for each of the tested models.

Levels recorded at close distance for a jet air dryer revealed an average of 59.5 colonies of yeast compared with an average of just 2.2 colonies for paper towels.

At a distance of 0.2 m the jet air dryer recorded 67 colonies of yeast compared with only 6.5 for paper towels. At a distance of 1.5 m the jet air dryer recorded 11.5 colonies of yeast compared to zero for paper towels.

The research also looked at the body height at which microbes were spread by air dryers.

It found the greatest dispersal was at 0.6 – 0.9 m from the floor, the face height of small children who might be standing near the dryer when a parent is drying his or her hands.

Leading researcher Keith Redway said: “These findings clearly indicate that single-use towels spread the fewest microbes of all hand-drying methods.

“Cross contamination in public washrooms is a legitimate public health concern. The extent to which jet air dryers disperse microbes into the washroom environment is likely to have implications for policy guidance to facilities managers operating in a wide range of environments from sports venues and airports through to schools and hospitals.”

But Dyson, a major hand dryer manufacturer, strongly disputes the study’s findings.

A spokesperson said: “The paper towel industry has consistently failed to invent new technology or respond to environmental concerns.

“Paper towels are costly to buy and replace, and are rarely recycled, meaning they are sent to landfill or incinerated. To argue their case, the paper towel industry is continuing to commission research with flawed methodology.

“A study conducted by Campden BRI’s (an independent membership-based organisation carrying out research and development for the food and drinks industry worldwide) hygiene specialists found that there are no practical differences between any of the hand drying techniques investigated (paper towels, conventional air dryers and the Dyson Airblade) with regard to microbial aerosol generation.

“The very low numbers of airborne microbes resulting from use of each of the hand dryers would make an insignificant contribution to the overall background microbial loading of the air.”

handwash_infosht-2-7-08 copy

But handwashing is never enough: Ireland says wash hands after farm visits

As the weather improves and visits to outdoor farms increase, the Health and Safety Executive for Northern Ireland (HSENI) is reminding parents and teachers of the importance of schoolchildren washing their hands after being in contact with animals.

handwash.UK.petting.zoo.09A visit to a farm and the chance to see and handle animals is an exciting time for young children.

However, it is vitally important to remember that farm animals can carry harmful bacteria such as E. coli, which can be transferred to children through contact with the animal or its faeces. If the child then goes on to eat, drink, or put their hands near their mouth, without washing their hands, there is a real risk of serious infection.

Urging everyone to follow simple hygiene steps to avoid spoiling anyone’s fun, Malcolm Downey who heads HSENI’s farm safety team said: “Anti-bacterial gels and wipes alone are not a substitute for properly washing your hands.”

Sorry Malcolm, it’s not that simple.

Our paper on human-animal interactions published in Zoonoses and Public Health, includes a 2-page checklist for parents, and the teachers who book these events.

Gonzalo Erdozain, Kate KuKanich, Chapman and I have all seen microbiologically terrible practices at petting zoos or in homes, and read about them from around the world, so we thought, maybe we should try and provide some guidance.

The uniting factor is we all have kids, and in my case, grandkids, and keep adding more.

claudia.e.coli.petting.zoo.may.14In Brisbane, they have the Ekka, something like the Texas State Fair. The petting zoo was absolute madness, and after living in Brisbane and hanging out with micro-types I got the message, don’t go to the Ekka, you’ll get sick. We didn’t go in 2013: 49 people, primarily kids, got sick from E. coli O157 (and in typical Queensland style, the outbreak has never been written up, there has been no follow-up, nothing; guess it would be bad for agriculture).

North Carolina has had repeated and terrible outbreaks.

As a father of five daughters, I’ve had many requests over 20 years to go on a school trip to see the animals. As a food safety type, I’ve been routinely concerned about best practices. The other parents may dislike microbiology, but I’m concerned with the health and safety of the children involved.

A table of petting zoo outbreaks is available at http://barfblog.com/wp-content/uploads/2014/04/Petting-Zoo-Outbreaks-Table-4-8-14.xlsx.

Best practices for planning events encouraging human-animal interations

Zoonoses and Public Health 62:90-99

Erdozain , K. KuKanich , B. Chapman and D. Powell, 2015

http://onlinelibrary.wiley.com/doi/10.1111/zph.12117/abstract?deniedAccess
 Educational events encouraging human–animal interaction include the risk of zoonotic disease transmission. ‘It is estimated that 14% of all disease in the USA caused by Campylobacter spp., Cryptosporidium spp., Shiga toxin-producing Escherichia coli (STEC) O157, non-O157 STECs, Listeria monocytogenes, nontyphoidal Salmonella enterica and Yersinia enterocolitica were attributable to animal contact. This article reviews best practices for organizing events where human–animal interactions are encouraged, with the objective of lowering the risk of zoonotic disease transmission.

petting1-791x1024

 

 

 

 

petting2-791x1024

The Brits have a way with language: townies wash their hands

Germs. You can’t get away from the blighters. If it’s not the teeming populations of camplylobacter that infest the cavities of supermarketchicken, it’s the E coli, salmonella and worse that disport themselves on our towels and dishcloths.

courtlynn.handwashAgainst these regiments of invisible enemies we deploy a vast arsenal of weapons-grade cleaning products. But while we’re spraying our surfaces with bleach and washing our dishes in Eucalyptus detergent, a shaming 60-odd per cent of us neglect to wash our hands after we’ve visited the loo, according to a Rentokil survey.

While confirming my conviction that you’re better off eating dinner at home, where at least the bugs are mostly familiar, this news has made me reflect on my own handwashing habits which are, I realise, completely perverse.

At home in London, I carry on like Lady Macbeth, washing my hands dozens of times a day. But at weekends, in the stableyard, I find myself cheerfully eating a sandwich from an unwashed hand that moments ago was feeding a horse a mint.

I’ve no idea whether it is my scrupulous townie cleanliness or my robust rural exposure to pathogens that means I’m almost never ill. But either way I view with misgiving Rentokil’s proposed solution to the handwashing recidivists. Stewart Power, its marketing director, predicts that one day every washroom will have a monitoring system “to give us a nudge to wash our hands”.

It’s bad enough being nagged by an electronic voice about an unexplained item in the bagging area. Just imagine the irritation of being slut-shamed by a disembodied nanny in the loo door.

Hepatitis A, vaccination, handwashing and all that stuff: we all need someone we can lean on

My latest from Texas A&M’s Center for Food Safety:

I experimented in university.

powell's.food.safety.world.feb.15Who didn’t?

My experiments in the 1980s involved tomato plants, Verticillium resistance, using a midwife to deliver our children, and saying no to the pertussis vaccine.

My ex-wife and I prided ourselves on our evidence-based approach to things, but as pertussis vaccine safety improved, so has my advice to the two oldest kids who have kids of their own: (or are about to): get vaccinated.

A couple of weeks after U.S. Senator Bozo declared that handwashing in food service places like Starbucks could be voluntary, I’ve contemplated that position and concluded sure: with a couple of conditions.

I co-wrote a paper that declared food safety inspections and audits were not enough.

What I have always said is this: government inspections are a minimal standard but necessary to hucksters accountable. The best will always go above and beyond what is expected.

Consumers should seek out those who market microbial food safety and steer clear of hucksterism.

But retailers are reluctant to market food safety.

And it’s the retailers who are the burden in this food safety stuff: they preach but they don’t practice.

In addition to the personal tragedies, every outbreak raises questions about risk and personal choice.

It’s true that choice is a good thing. People make risk-benefit decisions daily by smoking, drinking, driving, and especially in Brisbane, cycling.

But information is hard to come by.

I went to a supermarket in Brisbane, after taking my daughter to school, and was shocked to find Nanna’s berries – those linked to a growing hepatitis A outbreak — on the frozen shelves.

I asked the woman at checkout, weren’t those berries recalled?

nannas-rasberriesShe said, only the mixed ones.

I said, the raspberries and blueberries you’re selling are coming from the same source.

She shrugged and said, not in the recall.

They were recalled the next day.

With at least 14 Australians now confirmed ill with hepatitis A from frozen berries apparently grown in China, the case presents a microcosm of intersecting interests of global food, vaccination fears, poor handwashing and xenophobia (which Australians are particularly good at; as John Oliver said, “Australia is one of the most comfortably racist places I’ve ever been in. They’ve really settled into their intolerance like an old resentful slipper”).

The complacency of Australian regulators is astounding when compared to other Western-style food safety agencies.

There was limited notice of the recall from state and federal food safety agencies until they all turned up for work on Monday: people eat seven days a week.

The company involved, Patties Foods in Bairnsdale in regional Victoria, repacks frozen berries grown who knows where (China and Chile in this case, apparently).

For those worried about Hepatitis A:

  • Get vaccinated. It’s been mandatory in Canada and several U.S. states for five years. It was mandatory for us to emigrate to Australia four years ago. It should be mandatory for locals. If I ran a restaurant, I’d want everyone to be vaccinated.
  • Wash your hands. Hepatitis A is one of the few foodborne diseases that is only spread human-to-human. And, like most foodborne illness, it’s fecal-oral. The typical U.S. scenario is a 20-something goes to Mexico or the Dominican for a friends wedding (and where hep A is endemic), comes back and is serving salad to a few thousand people at their part-time job. But it’s not just the person is positive: The same person also failed to adequately wash their hands after having a poop, and ended up making your lunch. And was not vaccinated.
  • Know your suppliers. I’ve talked with a lot of parents at my daughter’s school in the past few days and they are all concerned. But usually for the wrong reasons. It is incumbent on the supplier – and the retailers who market this crap – to provide safe food. They’re the ones who make money.

Food porn is everywhere, but microbiology involves some basics: that’s why there’s vaccines, that’s why milk is pasteurized; that’s why we don’t eat poop (and if we do, make sure it’s cooked).

That’s why I have a bunch of tip-sensitive digital thermometers for my daughter’s school.

If someone wants to promote public disclosure of handwashing compliance and is able to prove it, great.

Otherwise, you’re just a talker, not a doer.

Dr. Douglas Powell is a former professor of food safety at the University of Guelph in Canada and Kansas State University in the U.S., who shops, cooks and ferments from his home in Brisbane, Australia.

dpowell29@gmail.com

0478 222 221

Hep A is fecal-oral: Rosa’s Restaurant cited with handwashing violations shortly before Hepatitis A outbreak

Any time there is an outbreak of Hepatitis A, it’s not just a lack of vaccination, not just about identifying those at risk and giving them a shot, it’s about poop.

hepatitis.ASpecifically, that person making your salad went #2 and failed to properly wash their hands.

The Trentonian reports that the month before a Rosa’s Restaurant employee was diagnosed with Hepatitis A — sending residents scrambling for vaccinations — the eatery was cited for numerous handwashing violations.

According to an Oct. 8 food inspection report obtained by The Trentonian through a public records request, the restaurant was listed as out of compliance for employees conducting handwashing in a timely manner, workers performing proper handwashing and the business providing paper towel for handwashing facilities.

Also marked as a violation, an employee was observed making sandwiches and handling rolls with his bare hands, while another worker was shredding and handling lettuce with his bare hands, the report states.

“Due to the number of critical violations, the person in charge is not demonstrating proper knowledge of food safety principles pertaining to this operation,” Hamilton Township food inspector Kelly A. Thomas wrote in her report, which gave the restaurant a conditionally satisfactory evaluation. “No proof of food handling certification was available on-site at time of inspection.”

In response to the October report and some of the continued handwashing violations throughout the years, restaurant owner Rosa Spera said in an email on Friday that her establishment has four handwashing sinks.

“On past inspections some of the signs reminding workers to wash their hands have been missing,” Spera stated. “Unfortunately, sometimes people remove the

After the first case of Hepatitis A was reported in late November, officials disclosed three other Hamilton area residents contracted the virus that had eaten at Rosa’s during the time period the worker was affected.

MrHankyHowever, township officials previously stated that it does not know with any certainty that any of the three cases had any link to or is a direct result of the original incident.

Spera said in the email it’s “unfortunate” that one of her workers got sick in November.

“When he did, he reported immediately to a doctor, not to work,” Spera stated. “When I learned of it, I took immediate action to take every precaution. With the guidance of the Hamilton Health Department, we threw away all open food and had the township observe our deep cleaning of all food areas.”

Jeff Plunkett, the township’s health officer, said in an interview on Tuesday, that the restaurant was closed for approximately seven to eight hours on Dec. 1.

“They had to remove the entire staff, bring an entire staff new that hadn’t worked there during that period of communicability when the gentleman was sick,” Plunkett said. “The entire place was clean and sanitized and witnessed by an inspector who was there the entire time.”

But even as the health inspector stressed the importance of wearing gloves on Dec. 1, Thomas stated in her report that she observed an employee slicing and handling bread with his bare hands. Two days later, Thomas stated she observed employees doing prep work scramble to put on gloves as she walked through the doors, while another employee put on gloves without washing his hands first, inspection documents read.

Name and shame, Victoria style

That’s Victoria, the Australian state, where 25 per cent of the name and shame offences in food service directly related to a lack of training.

trainingGrace Smith writes for the Australian Institute of Food Safety that once an eatery has been discovered to breach Standard 3.2.2 Clause 3(1) (b) of the Food Act S16 (1), their details are added to the register for twelve months where the public can access details about their misconduct. The clause demands that all food-based establishments are responsible for ensuring that the people who are supervising or undertaking food handling operations must have “knowledge of food safety and food hygiene matters”.

Some of the establishments that were charged with failing to comply with food safety training laws include:

Milk Torquay Pty Ltd: Fined $6000.00 as part of their aggregate order, with $10,000 costs.

High Street Bakers and Confectioners of Thornbury: Fined $40,700.00 as part of their aggregate order with $1,300.00 costs.

Dream Cakes Café of Oakleigh: Fined $5,000.00 as part of their aggregate order with $6009.35 costs, and $10,000 in another aggregate order with $6009 costs.

While it’s safe to say that these convicted vendors were found guilty of various breaches, including handwashing and cleanliness problems, it’s shocking to imagine that in 2014, restaurants, cafes, and eateries are still staffed by individuals ignorant of food safety matters.

The federal legislation in Australia currently states that all people who are responsible for handling food must undertake food safety training appropriate to their position. The law also requires that businesses comply with the Food Standards Code – a collection of individual food standards that was jointly developed by professionals in Australia and New Zealand. Providing people with food that does not meet this code is a criminal offence.

Furthermore, the state legislation in Victoria outlines that every business dealing with food must have a Food Safety Supervisor on staff who is reasonably contactable at all times. The Food Safety Supervisor must have completed a mandatory training course and is responsible for preventing, monitoring and dealing with food safety issues as they arise, as well as being responsible for the ensuring all food handlers are trained appropriately in food safety.

Republican senator says restaurants should be able to opt-out of mandatory handwashing

As Republican presidential hopefuls like Rand Paul and Chris Christie fall over themselves to claim the live-free-or-die vote by saying vaccinations should be optional, North Carolina Senator Thom Tillis has gone further: laws requiring mandatory handwashing by food service employees are just regulatory burden.

handwashing.sep.12According to Daily Kos, Tillis made the declaration at the Bipartisan Policy Center, at the end of a question and answer with the audience. He was relaying a 2010 anecdote about his “bias when it comes to regulatory reform.”

“I was having a discussion with someone, and we were at a Starbucks in my district, and we were talking about certain regulations where I felt like ‘maybe you should allow businesses to opt out,’” he said, “as long as they indicate through proper disclosure, through advertising, through employment literature, or whatever else.”

Restaurants can just opt-out and let the free market take care of business after word spreads of unsanitary conditions.

“That’s the sort of mentality that we need to have to reduce the regulatory burden on this country,” he added. “We’re one of the most regulated nations in the history of the planet.”

Bipartisan Policy Center President Jason Grumet joked that he was “not sure” he would shake Sen. Tillis’ hand when the discussion was over, causing the lawmaker and members of the audience to laugh.

With a check by Schaffner: How to avoid food poisoning at home

Science is about disagreements, revising knowledge and generating new evidence-based knowledge (someone will disagree with that).

Don-Schaffner-214x300Don Sapatkin of the Philadelphia Inquirer recently asked a number of food safety types about food safety at home. For fun, I asked friend of the barfblog and known bugcounter, Don Schaffner of Rutgers University (left, prettymuch as shown) his thoughts on the answers.

“Washing a sponge with soap doesn’t get rid of bacteria,” said microbiologist Michael Doyle, director of the University of Georgia’s Center for Food Safety (below, right). They grow at room temperature and get spread around anything else you wipe off. Put the sponge in a microwave for one minute to kill the salmonella and other bacteria,” he said.

Schaffner: Sort of true. Washing a sponge will probably remove some bacteria, but not all. Same with the microwave: it depends upon the microwave, the amount of moisture in the sponge, etc. A better practice may be to put your sponges in the automatic dishwasher, assuming you have one.

 Experts say most home kitchens are far dirtier.

Schaffner: Might be true, but science-based head-to-head comparisons are lacking.

 Cutting boards should not have hard-to-clean nicks and grooves (wood is better, Doyle said, because the resin has antibacterial properties).

Schaffner: Dean Cliver’s work showed wooden cutting boards to be safer, but the literature is far from clear on the matter.

 Washing chicken in the sink may sound hygienic but actually poses all sorts of risks.

Schaffner: Yup, this has good scientific consensus.

 “Every time you run your disposal in the sink you are generating a little airflow back up.”

michael.doyle.produce.07Schaffner: Yup, probably true.

 If you do wash chicken in the sink, clean it (the sink) with bleach (1 ounce in 1 gallon of water).

Schaffner: Giving bleach concentration recommendations always concerns me. The units are never the same, the knowledge about the type of bleach is never certain, and the type of surface being cleaned makes a difference (plates versus countertops).  I used to dream of creating a webpage that would definitively answer these questions, and do unit conversions. Now I have the same dream except it’s an iPhone app.

Craig Hedberg, a professor at the University of Minnesota School of Public Health (below, left): “If you take this big mass of hot food and put it into a plastic container and put a lid on it, you are holding the heat in and slowing the cooling process, even if you put it in the refrigerator. You want to get it out of bacterial-growth range” – 40 to 140 degrees – “within a couple of hours.” Pouring it into containers no more than four inches deep speeds the process.

Schaffner: This is more or less correct, but I believe the correct depth of the food recommendation is 3 inches. It doesn’t really matter how deep the container is, it’s the depth of the food.

If food is not cooled fast enough, spores that survived cooking can germinate and grow bacteria. Reheating leftovers to 165 degrees for 15 seconds will kill them.

Schaffner: This is the general time temperature recommendation. I’ve never checked to see what log reduction it would give for Clostridium perfringens cells, but it’s likely sufficient.

Hedberg advises against washing prewashed bagged lettuce; E. coli and salmonella can adhere to cut surfaces and tiny pores. “If it’s contaminated, your washing it again would not eliminate the contamination,” he said. “If it is not contaminated, your washing may contaminate it.”

Schaffner: That is consistent with expert recommendations.

 Hands should be washed vigorously with soap before preparing food or eating; after handling raw meat, poultry, fish, or even raw produce; and after smoking, eating, or drinking.

Craig HedbergSchaffner: Also after pooping or changing a diaper, handling pets etc.

 Countertops, cutting boards, utensils, etc., should be cleaned with hot water after every use.

Schaffner: I also recommend soap.

 Cooking and holding temperatures should be checked, which means having working thermometers. (The fridge should be set between 32 and 40 degrees Fahrenheit; the freezer, at zero or below).

Schaffner: They nailed this one.

 Everything should be clean: Garbage covered, or at least three feet from food-preparation areas; pets never allowed in the kitchen (and hands washed after petting).

Schaffner: I’m not sure where the three-foot recommendation comes from, and it’s probably not science-based. Does anyone really exclude their pets from the kitchen? When we had dogs their food and water dishes were in the kitchen. Good luck getting a cat to do anything you want to do.

To bring home cooks up to speed, the Rutgers University Cooperative Extension posts a quick home kitchen food safety best practices check-Up list: http://bit.ly/1xDO19F.