42: Tea towels a source of bacteria in kitchen

Posted on June 30, 2018 by Douglas Powell

I was never a paper towel kinda guy.

I have about 30 tea towels, including one with images of all of Sorenne’s prep (kindergarten) pals and teachers.

They are my go-to sweat rags, hand wipes and kitchen cleaner-uppers.

As advised by The Hitchhikers’ Guide to the Galaxy, never leave home without a towel.

About five go into the laundry every day.

According to a study published by the University of Mauritius, and presented recently at the annual meeting of the American Society for Microbiology, your kitchen towels may be the leading culprit of pathogen advancement.

“Our study demonstrates that the family composition and hygienic practices in the kitchen affected the microbial load of kitchen towels,” said Dr. Biranjia-Hurdoyal. “We also found that diet, type of use and moist kitchen towels could be very important in promoting the growth of potential pathogens responsible for food poisoning,” she said.

Researchers collected a total of 100 kitchen towels after one month of use. Using standard biochemical tests, they concluded that 49% of the kitchen towels collected in the study had bacterial growth. The bacterial growth increased in number with family size—whether by extended family, or the presence of children.

Experts discourage using kitchen towels for multiple purposes (wiping utensils, drying hands, holding hot utensils, wiping/cleaning surfaces) because they had a higher bacterial count than single-use towels. They also warn against using humid towels because they too showed higher bacterial count than dry ones. Pathogens on kitchen towels would indicate that they could bear some responsibility for cross-contamination in the kitchen and, ultimately, food poisoning. Households with children, older adults or others with immunosuppression should be especially vigilant about hygiene in the kitchen.

But, like other studies of sponges and things, the researchers don’t account for the level of cleaning in a particular household. Five a day, into the laundry.

And rather than blame consumers, have a look at bacterial loads on chef aprons.

Flyslayer: Flies transport Campylobacter in the kitchen

Posted on May 3, 2016 by Douglas Powell

I hate flies.

As a kid I would occupy myself for hours in my grandfather’s barn, swatting to death as many flies as I could. Sure it was futile, and a good indicator of life-long neuroses, but I sure like killing them.

Many of the houses in Brisbane don’t have screens. We paid extra to have screens installed in our new townhome. But the neurotic cats have to hang out on the balcony so the screens sometimes stay open and flies swoop in to soil my lovingly prepared meals.

My daughter calls me Flyslayer.

My partner bought me this battery-charged, tennis-racquet sized flyswatter so I can zap flies mid-flight.

Here’s why:

The house fly, Musca domestica, has been implicated as a vector of Campylobacter spp., a major cause of human disease. Little is known whether house flies serve as biological amplifying hosts or mechanical vectors for Campylobacter jejuni.

We investigated the period after C. jejuni had been ingested by house flies in which viable C. jejuni colonies could be isolated from whole bodies, the vomitus and the excreta of adult M. domestica and evaluated the activation of innate immune responses of house flies to ingested C. jejuni over time. C. jejuni could be cultured from infected houseflies soon after ingestion but no countable C. jejuni colonies were observed > 24 hours post-ingestion. We detected viable C. jejuni in house fly vomitus and excreta up to 4 hours after ingestion, but no viable bacteria were detected ≥ 8 hours. Suppression subtractive hybridization identified pathogen-induced gene expression in the intestinal tracts of adult house flies 4-24 hours after ingesting C. jejuni. We measured the expression of immune regulatory (thor, JNK, and spheroide) and effector (cecropin, diptericin, attacin, defensin and lysozyme) genes in C. jejuni-infected and -uninfected house flies using quantitative real time PCR. Some house fly factor, or combination of factors, eliminates C. jejuni within 24 hours post-ingestion.

Because C. jejuni is not amplified within the body of the housefly, this insect likely serves as a mechanical vector rather than as a true biological, amplifying vector for C. jejuni, and adds to our understanding of insect-pathogen interactions.

Campylobacter jejuni in Musca domestica: An examination of survival and transmission potential in light of the innate immune responses of the house flies

Insect Science. doi: 10.1111/1744-7917.12353.

Gill, S. Bahrndorff, and C. Lowenberger

http://www.ncbi.nlm.nih.gov/pubmed/27134186

‘I don’t think I ever had food poisoning’ Food safety as part of the household

Posted on February 2, 2015 by Douglas Powell

Food stored, prepared, cooked and eaten at home contributes to foodborne disease which, globally, presents a significant public health burden. The aim of the study reported here was to investigate, analyse and interpret domestic kitchen practices in order to provide fresh insight about how the domestic setting might influence food safety.

Using current theories of practice meant the research, which drew on qualitative and ethnographic methods, could investigate people and material things in the domestic kitchen setting whilst taking account of people’s actions, values, experiences and beliefs.

Data from 20 UK households revealed the extent to which kitchens are used for a range of non-food related activities and the ways that foodwork extends beyond the boundaries of the kitchen.

The youngest children, the oldest adults and the family pets all had agency in the kitchen, which has implications for preventing foodborne disease. What was observed, filmed and photographed was not a single practice but a series of entangled encounters and actions embedded and repeated, often inconsistently, by the individuals involved.

Households derived logics and principles about foodwork that represented rules of thumb about ‘how things are done’ that included using the senses and experiential knowledge when judging whether food is safe to eat.

Overall, food safety was subsumed within the practice of ‘being’ a household and living everyday life in the kitchen. Current theories of practice are an effective way of understanding foodborne disease and offer a novel approach to exploring food safety in the home.

‘I don’t think I ever had food poisoning’ A practice-based approach to understanding foodborne disease that originates in the home

Appetite, Volume 85, 1 February 2015, Pages 118–125

Wendy J. Wills1, Angela Meah, Angela M. Dickinson, Frances Short

http://www.sciencedirect.com/science/article/pii/S0195666314005443

Research: 90 percent of home chefs contaminate food

Posted on February 2, 2015 by Douglas Powell

In an effort to evaluate current food safety messages, researchers at Kansas State University videotaped home chefs preparing a meal containing raw meat and a ready-to-eat fruit salad. The raw meat was inoculated with a nonpathogenic organism to trace contamination in the kitchen. The researchers found that 90 percent of the participants had contaminated their salad.

“Almost all of the fruit salads we analyzed contained levels of the tracer organism, which we were representing as being salmonella,” said Randy Phebus, professor of food safety at Kansas State University and one of the authors of the study “Consumer Food Handling Practices Lead to Cross-Contamination,” recently published in the journal Food Protection Trends.

The purpose of the research — funded by the U.S. Department of Agriculture Food Safety and Inspection Service — was to determine which type of food safety messaging resulted in the best food-handling practices. The 123 participants were divided into three groups. One group was given an education program on the four national Food Safety Families campaign messages of clean, separate, cook and chill; one group viewed and discussed the Ad Council public service announcements focusing on the same four Food Safety Families messages; and one group did not receive any food safety training before preparing a meal.

The study found that all participants made mistakes in the kitchen that could lead to potential foodborne illnesses. The researchers wiped down the kitchen after each participant prepared a meal, finding most participants tracked contaminations all around the kitchen, including on handles, countertops, faucets and trash cans. But contamination was especially prevalent on hand towels.

“We found that most people tried to wash their hands, but did it very ineffectively — either only using water or not washing for long enough,” Phebus said. “By not washing their hands correctly, they spread contamination to the hand towels. They then go back to those towels multiple times and recontaminate themselves or the kitchen surfaces with those towels. It ultimately leads to contamination in the food product.”

Participants who received food safety messages before cooking did slightly better at this task than those who received no messages, but the differences were subtle. This research highlights the difficult task for food safety practitioners of not only informing consumers, but also changing their habits, Phebus said.

Bacterial occurrence in kitchen hand towels

Posted on August 31, 2014 by Douglas Powell

People don’t use dryers much in Brisbane. It hardly rains, so people use clotheslines, and electricity is expensive.

And it’s so natural.

My clothsline can usually be found with an abundance of hand (or tea) towels.

I use them all the time when cooking and am fastidious about washing them.

I also wonder how often those cook aprons are washed.

Gerba et al. report the common occurrence of enteric bacteria in kitchen sponges and dishcloths suggests that they can play a role in the cross-contamination of foods, fomites and hands by foodborne pathogens. This study investigated the occurrence of bacteria in kitchen towels often used to dry dishes, hands and other surfaces in the domestic kitchen. A total of 82 kitchen hand towels were collected from households in five major cities in the United States and Canada and the numbers of heterotrophic bacteria, coliform bacteria, and Escherichia coli in each towel were determined. In addition, identification of the enteric bacteria was performed on selected towels. Coliform bacteria were detected in 89.0% and E. coli in 25.6% of towels. The presence of E. coli was related to the frequency of washing.

Norovirus: it’s everywhere and you still don’t want it

Posted on July 14, 2014 by Douglas Powell

Ingeborg et al. report in Food Control that Noroviruses (NoV) are among the most common causes of viral gastroenteritis (GE) worldwide and can be transmitted from person-to-person, via food or contaminated surfaces. The present study aimed to examine the prevalence of NoV RNA on surfaces in food preparation and sanitary areas in different health care settings and to compare the outcomes with the prevalence in nearby located catering companies, mainly restaurants, for general public, as sentinels.

For this purpose, 1087 environmental swabs were taken for NoV analyses from surfaces in 241 institutional departments and 123 catering companies in The Netherlands without a recently reported outbreak of gastro-enteritis in high NoV season only. NoV RNA was detected in 15.1% of the 73 non-hospital health care institutions, 11.1% of the 54 hospital central kitchen departments, 14.9% of the 114 decentralized hospital kitchens (in-patient units) and 4.1% of the 123 nearby located catering companies. Twenty-five of the 49 positive environmental samples were genotyped by sequence analyses. In 7% of the investigated hospitals (4/58), NoV was detected in two or more departments. NoV prevalence was significantly lower in food preparation areas than in sanitary facilities (p < 0.05), but only in hospital central kitchen departments and non-hospital health care settings, and not in de-centralized hospital kitchens in in-patient units or in catering companies for the general public. This data suggests that there is a need for education on risks of NoV transmission by food handling of healthcare workers using in ward kitchen facilities.

Environmental testing for norovirus in various institutional settings using catering companies as sentinels for norovirus prevalence among the general population

ScienceDirect

Ingeborg L.A. Boxmana, Linda Verhoefb, Geke Hägelea, Kyara Klundera, Nathalie A.J.M. te Loekea, Harry Vennemab, Claudia C.C. Jansena, Marion Koopmans

Food Control, Volume 47, January 2015, Pages 98–102, DOI: 10.1016/j.foodcont.2014.06.026

http://www.sciencedirect.com/science/article/pii/S0956713514003557

Tea towels should only be used once, then washed?

Posted on July 6, 2014 by Douglas Powell

Never be anywhere without a towel.

A tea towel (or dish towel).

But do I need 50 clean ones a day?

New South Wales Food Authority chief scientist Lisa Szabo said last week that, “Tea towels should be replaced after every use. … It’s best to wash tea towels after each use and have a good supply of fresh ones to hand.”

That’s a lot of washing for anyone who has cooked from scratch.

So I reached out to friend of the barfblog, Dr. Don ‘Data’ Schaffner, who offered what seems to be reasonable advice: use disposable paper towels after a handwash where pathogens may be present, and a dish towel for other things. He has a paper coming out on the topic, but is a strong believer, like me, in peer-review and publish before press release.

PR before publication still bad idea; people pushing Lysol cite cross-contamination

Posted on June 20, 2012 by Douglas Powell

In Sept. 2000, I called Procter & Gamble to substantiate claims their consumer-oriented Fit Fruit and Vegetable Wash removed 99.9 per cent more residue and dirt than water alone.

The PR-thingies hooked me up with some scientists at P&G in Cincinnati, who verbally told me that sample cucumbers, tomatoes and the like were grown on the same farm in California, sprayed with chemicals that would be used in conventional production, and then harvested immediately and washed with FIT or water. The Fit removed 99.9 per cent more, or so the company claimed.

One problem. Many of the chemicals used had harvest?after dates, such as the one tomato chemical that must be applied at least 20 days before harvest.

That tidbit wasn’t revealed in the company PR accompanying Fit.

Residue data on produce in North American stores reveals extremely low levels, in the parts per million or billion. So that 99.9 per cent reduction was buying consumers an extra couple of zeros in the residue quantity, all well below health limits.

Sorta like the annual crap survey produced by the Environmental Working Group that came out today, with its produce dirty dozen.

Back in 2000 I asked why the results hadn’t been published in a peer-reviewed journal, and the P&G types said it was an important advance that had to be made available to consumers as soon as possible, without the delays and messiness of peer-review.

Press release before publication is always a bad idea – cold fusion?

Today, something called the Hygiene Council flogged a press release touting a study showing meal preparation can contaminate up to 90 per cent of kitchen surfaces touched.

In the 2012 Lysol Cross-Contamination Study, volunteers were asked to prepare a chicken stir-fry, fresh green salad, and packed kids’ lunch. Results showed significant cross-contamination in the kitchen, which spread to other hand-contact surfaces, kitchen towels, cloths and sponges.

Overall, hand hygiene was seen to be relatively poor. Volunteers were more likely to simply rinse their hands after touching raw chicken or vegetables than wash them with soap, even when it was provided. Just one participant in the study washed their hands with soap every time they touched raw chicken; and only two of the six participants washed their hands with soap before filling a child’s cup with water after touching raw chicken.

It is fairly common knowledge that raw chicken and other raw meats can carry harmful bacteria, but study results show that many people do not realize that raw veggies can as well, as evidenced by a deadly E. coli outbreak in Europe last summer from raw, unwashed vegetables.

None of the study participants washed their hands after touching raw vegetables, nor did they wash all of the salad items before eating them. When switching tasks, volunteers failed to use separate knives for preparing meat, vegetables, salad, and sandwiches. Consequently, chopping boards and knives were found to be contaminated in 92 per cent of cases.

This sounds like great stuff. So I was nerdly anxious to read the paper, examine the methodology and see what could be learned.

There is no paper. Maybe there will be, maybe it’s a great study, but without it, mere mortals rather than marketing titans have no way to assess its validity. Or validate the claims.

There were three elements to the study:

Volunteer study (microbiology): Six volunteers carried out a series of kitchen tasks and microbiological analysis was conducted on the surfaces/objects they touched to detect bacterial contamination

Volunteer study (observational): The same volunteers were observed and filmed. They were assessed against a number of hygiene behaviors to determine whether they used good or poor hygiene practices

Marker study: The same tasks as in the Volunteer Study were carried out by an environmental health practitioner (EHP). The study used foods deliberately contaminated with Serratia rubidaea, an easily detectable bacterium, to clearly show the potential spread of contamination and to compare the level of contamination caused when good or bad hygiene practices were used.

PR before publication is a bad idea.

Ozzie and Heston not welcome in my kitchen

Posted on March 31, 2012 by Douglas Powell

Dr. Oz did a show a couple of years ago, would your home pass a restaurant inspection?, that was broadcast the other day in Australia (Days of Our Lives is at least two years behind; it’s all background).

Forget the flaws in the methodology, the risk amplification inherent in feeding a family and feeding 1,000 people a day, the television nonsense: Dr. Oz willingly lets his cat on the kitchen food prep counter.

And Heston-norovirus-Blumenthal has great food prep tips, but still don’t know food safety. For his latest show (which may also be two years behind) he “takes off his chef whites and steps into a domestic kitchen to show viewers how to inject some Heston-style magic into homemade cooking.”

What I briefly saw was a Mitt Romney-styled I’m one of the boys segments, as a local rugby team arrived by boat at his country home and they all took a turn grinding beef for burgers on the barbie; outside on a table. Cross-contamination everywhere.

Who’s to blame? Campy cases up almost 50% in UK, Ireland

Posted on March 27, 2012 by Douglas Powell

Wales Online reports that sloppy food hygiene at home has been blamed for a worrying increase in cases of campylobacter food poisoning.

Carried by chickens, it is thought large numbers of raw chickens sold in supermarkets are infected with campylobacter, which can be spread to other foods in the kitchen via cross-contamination.

Tom Humphrey, a professorial fellow in food safety at the University of Liverpool, said: “Campylobacter doesn’t need any exaggerating; we don’t need to big up its importance. My daughter got it when she was seven and lost 7kg in two days. She was passing nothing but blood.

Official figures show there were 70,000 cases of campylobacter illnesses in the UK in 2010; the latest figures for Wales show there are some 3,000 a year but it is thought for every one reported case, a further 10 go unreported.

There were 2,440 official cases notified in the Republic of Ireland last year, a rise of 46.9pc over 2010.

Humphrey said because most poultry had campylobacter, “The importance, therefore, is very much on the careful handling of poultry. Studies have found campylobacter on domestic dishcloths, which is symptomatic of what is happening in the kitchen. We tend to take things for granted and can be a bit sloppy when it comes to food hygiene at home.

“All cows have campylobacter and all milk will have cow poo in it, if you don’t heat it, there’s a risk of campylobacter.

“Kittens and puppies can get diarrhea caused by campylobacter and, particularly for young children, being in contact with that is a risk factor.

“But overwhelmingly, the biggest factor is the consumption of under-cooked chicken – this makes up between 50% and 80% of cases.”

He added that intervention on the farm is the key to controlling campylobacter in chickens.

So is it the farm, home kitchens, food service, everywhere, what’s the message?

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