Several outbreaks of foodborne illness traced to leafy greens and culinary herbs have been hypothesized to involve cross-contamination during washing and processing. This study aimed to assess the redistribution of Salmonella Typhimurium LT2 during pilot-scale production of baby spinach and cilantro and redistribution of Escherichia coli O157:H7 during pilot-scale production of romaine lettuce.
Four inoculated surrogate: uninoculated product weight ratios (10:100, 5:100, 1:100, and 0.5:100) and three inoculation levels (103, 101, and 10−1 CFU/g) were used for the three commodities. For each of three trials per condition, 5-kg batches containing uninoculated product and spot-inoculated surrogate products at each ratio and inoculation level were washed for 90 s in a 3.6-m-long flume tank through which 890 L of sanitizer-free, filtered tap water was circulated. After washing and removing the inoculated surrogate products, washed product (∼23, 225-g samples per trial) was analyzed for presence or absence of Salmonella Typhimurium or E. coli O157:H7 by using the GeneQuence Assay.
For baby spinach, cilantro, and romaine lettuce, no significant differences (P > 0.05) in the percentage of positive samples were observed at the same inoculation level and inoculated: uninoculated weight ratio. For each pathogen product evaluated (triplicate trials), inoculation level had a significant impact on the percentage of positive samples after processing, with the percentage of positive samples decreasing, as the initial surrogate inoculation level decreased.
The weight ratio of contaminated: noncontaminated product plays an important role: positive samples ranged from 0% to 11.6% ± 2.05% and from 68.1% ± 33.6% to 100% among the four ratios at inoculation of 10−1 and 101 CFU/g, respectively.
To our knowledge, this study is the first to assess the redistribution of low levels of pathogens from incoming product to leafy greens during processing and should provide important data for microbial risk assessments and other types of food safety analyses related to fresh-cut leafy greens.
Transfer and redistribution of Salmonella typhimurium LT2 and Escherichia coli O157:H7 during pilot-scale processing of baby spinach, cilantro, and romaine lettuce
Journal of food Protection vol.81 no. 6 June 2018
HALEY S. SMOLINSKI,1 SIYI WANG,1 LIN REN,1 YUHUAN CHEN,2 BARBARA KOWALCYK,3 ELLEN THOMAS,3 JANE VAN DOREN,2 and ELLIOT T. RYSER1*
Cross-contamination is one of the main factors related to foodborne outbreaks. This study aimed to analyze the cross-contamination process of Salmonella enterica serovar Enteritidis from poultry to cucumbers, on various cutting board surfaces (plastic, wood, and glass) before and after washing and in the presence and absence of biofilm.
Thus, 10 strains of Salmonella Enteritidis were used to test cross-contamination from poultry to the cutting boards and from thereon to cucumbers. Moreover, these strains were evaluated as to their capacity to form biofilm on hydrophobic (wood and plastic) and hydrophilic materials (glass).
We recovered the 10 isolates from all unwashed boards and from all cucumbers that had contacted them. After washing, the recovery ranged from 10% to 100%, depending on the board material. In the presence of biofilm, the recovery of salmonellae was 100%, even after washing. Biofilm formation occurred more on wood (60%) and plastic (40%) than glass (10%) boards, demonstrating that bacteria adhered more to a hydrophobic material.
It was concluded that the cutting boards represent a critical point in cross-contamination, particularly in the presence of biofilm. Salmonella Enteritidis was able to form a biofilm on these three types of cutting boards but glass showed the least formation.
Cross-Contamination and Biofilm Formation by Salmonella enterica Serovar Enteritidis on Various Cutting Boards
01.feb.18
Foodborne Pathogens and Deases, Volume 15, No. 2
Dantas Stéfani T. A. , Rossi Bruna F. , Bonsaglia Erika C. R. , Castilho Ivana G. , Hernandes Rodrigo T. , Fernandes Ary Júnior, and Rall Vera L. M.
Campylobacter jejuni is an important human pathogen commonly associated with raw poultry. The risk of cross-contamination in the kitchen is escalated with washing raw poultry in the sink- an unnecessary measure for food safety. Cook the bird to an internal temperature of 74°C (165°F), no need for washing.
You’re spraying your sink with salmonella Washing your fruit? Absolutely. Washing your lettuce? Necessity. But running warm water over a slimy slab of raw chicken is just about the worst thing you can do with your kitchen sink. In fact, it’s such a bad idea that the National Health Service (NHS) in Britain issued a public warning against the “sanitary” practice — claiming that “it can increase your risk of food poisoning from campylobacter bacteria.” Chicken is one of the most commonly infected raw foods when it comes to foodborne bacteria such as salmonella. These bacteria lurk both on the surface and insides of the raw meat, growing indefinitely until you cook them dead. “Only a few campylobacter cells are needed to cause food poisoning,” the NHS says. Washing the chicken involves running tap water over that infested piece of meat. The water becomes contaminated as soon as it hits the surface of your poultry, and proceeds to splash in every direction both inside and around your kitchen sink. “Water droplets can travel more than 50 centimeters in every direction,” the NHS warns, a distance that equates to over one and a half feet. After that bacteria spreads, it’s hard to get rid of. The only real way to effectively kill the bacteria you’ve now sprinkled around your home is to disinfect everything — an onerous task you’re likely saving until after you’re done cooking. That means your risk of exposure is prolonged and the bacteria could even come into contact with your other food. If you’re preparing chicken, skip the washing step. The oven kills everything, anyway — and once a chicken is properly cooked, it’s 100 percent free of disease-causing bacteria. If you’re bored with bland old chicken and looking to spice things up, here are 101 of our best recipes.
I watched from the diner counter as my server bare handedly took bread from the storage drawer, toasted it, cut it, and put it on a plate. The manager who had been answering phones and rubbing his face while adjusting his glasses also made toast and wiped his hands on a kitchen towel that then disappeared to wipe something else down.
No imagination needed to see how something like E. coli or Norovirus could be spread as I watched each bit of contact affect all the bread, knives and surfaces.
Am I neurotic? I tried not to have a stomachache.
I just want toast.
Rebecca Fischer (laughingkat2@gmail.com) says she’s in the middle of a career change, following my passion for food by studying nutrition. Food handling has become a fascination, another excuse for people-watching, to see how experience and education affect awareness in kitchen behavior.
And I may be on hiatus but I’m a sucker for helping students who want to learn and kids –little or big — who want to play hockey.
The number of infections usually peaks during the late summer months then drops off, but this year has yet to see a notable downward curve, Sweden’s Public Health Agency (Folkhälsomyndigheten) warns.
The growth coincides with an increase in campylobacter among flocks of chicken in Sweden, and fresh chicken is therefore thought to be a culprit.
“The explanation we have right now is that we eat a lot of chicken. We eat a lot of fresh chicken, and campylobacter can be found in the fresh chicken to a certain extent,” Folkhälsomyndigheten spokesperson Britta Björkholm noted.
“If you’re not careful with your hygiene you risk coming down with it,” she added.
Between August and November 2016 twice as many cases were reported as normal, and that pattern has continued into the last month of the year.
About 100 cases are usually reported in December, but in December 2016 the number was almost 300 by the middle of the month.
“People are not being sufficiently careful about separating raw chicken from utensils and work surfaces,” Björkholm insisted.
He rarely eats in restaurants. When he dines at friends’ homes, he’s been known to peek into his hosts’ fridge and cupboards. “It’s an annoying habit,” he tells the Daily News.
Meet Doug Powell (right, exactly as shown, in 2005, dissenters to the left please) a former professor of food safety and publisher of barfblog.com, which is all about food-safety issues. There are plenty of them. Last year there were 626 food recalls in the U.S. and Canada. The Centers for Disease Control and Prevention estimate that food-borne pathogens sicken 48 million Americans — that’s one in six — hospitalize 128,000 and kill 3,000. Powell, who was raised in Canada, lived in the U.S. and now resides in Brisbane, Australia, has been there. He wrote about that in barfblog. “More recalls are due to better detection and awareness,” he says. “The food is as dangerous as it’s always been, not more so.”
Between posting about recalls and E. coli outbreaks in the U.S. and beyond, Powell, 53, set the Daily News straight about everyday food-safety questions.
Now it’s okay to eat pork that’s rosy pink, right?
Nope. “Research has shown that color is a lousy indicator of whether meat is safe to eat,” says Powell. Same goes for requesting your chops or steaks “well done,” which is vague enough to put you in hurl’s way. “When I go to a restaurant and they ask me how I want my steak, I say, ‘140 degrees.’” He also carries a tip-sensitive digital thermometer in his backpack. He swears by one from Comark that’s around $16.
Raw sprouts are good for you, yes?
Maybe not. “I never eat them,” says Powell. And that includes ones he could grow at home. Warm and humid conditions ideal for growing sprouts are an Eden for growing bacteria, like Salmonella, Listeria, and E. coli. In the past 20 years they’ve been connected to at least 30 outbreaks of foodborne illness (bring on your best shots, left, I got some new goalie equipment, 11 years later).
You should have two cutting boards in the kitchen — one for meat, the other for vegetables?
Powell uses one and “usually I use dish soap” to clean it. To sanitize, he uses a 10-to-one ratio of bleach to water.
(Nosestretcher alert: I already sent in the correction, which is somewhere between 250-400 parts water to I part bleach, or a tablespoon bleach per gallon of water.)
Is organically raised food safer than if it’s conventionally produced?
Nope. “Organic is a production standard and has nothing to do with microbial food safety,” says Powell. “Large or small, conventional or organic, safety is a function of individual farmers. They either know about microbial food safety risks and take steps to reduce or manage that risk, or they don’t.” Along the same line, “local” does not automatically mean safe, he adds.
Super-fresh sushi won’t make you sick will it?
“Raw fish houses an amazing microbiology profile that can make you sick,” he says. “It’s just not a good idea to eat it.”
Chapman says whenever someone calls him Ace, he responds with Ace of Spades, in a bad imitation of Lemmy’s voice.
Three different levels of inoculation of beef fillets surface were prepared: a high one of approximately 107 CFU/cm2, a medium one of 105 CFU/cm2 and a low one of 103 CFU/cm2, using mixed-strains of Listeria monocytogenes, or Salmonella enterica Typhimurium, or Escherichia coli O157:H7. The inoculated fillets were then placed on 3 different types of surfaces (stainless steel-SS, polyethylene-PE and wood-WD), for 1 or 15 min. Subsequently, these fillets were removed from the cutting boards and six sequential non-inoculated fillets were placed on the same surfaces for the same period of time. All non-inoculated fillets were contaminated with a progressive reduction trend of each pathogen’s population level from the inoculated fillets to the sixth non-inoculated ones that got in contact with the surfaces, and regardless the initial inoculum, a reduction of approximately 2 log CFU/g between inoculated and 1st non-inoculated fillet was observed. S. Typhimurium was transferred at lower mean population (2.39 log CFU/g) to contaminated fillets than E. coli O157:H7 (2.93 log CFU/g), followed by L. monocytogenes (3.12 log CFU/g; P < 0.05). Wooden surfaces (2.77 log CFU/g) enhanced the transfer of bacteria to subsequent fillets compared to other materials (2.66 log CFU/g for SS and PE; P < 0.05).
Cross-contamination between meat and surfaces is a multifactorial process strongly depended on the species, initial contamination level, kind of surface, contact time and the number of subsequent fillet, according to analysis of variance. Thus, quantifying the cross-contamination risk associated with various steps of meat processing and food establishments or households can provide a scientific basis for risk management of such products.
Effect of inoculum size, bacterial species, type of surfaces and contact time to the transfer of foodborne pathogens from inoculated to non-inoculated beef fillets via food processing surfaces
In 2004, my laboratory reported (and by reported I mean published in a peer-reviewed journal) that, based on 60 hours of detailed viewing of television cooking shows, an unsafe food handling practice occurred about every four minutes, and that for every safe food handling practice observed, we observed 13 unsafe practices. The most common errors were inadequate hand washing and cross-contamination between raw and ready-to-eat foods.
The abstract is below.
Once the paper was published, it made headlines around the globe.
And then it started getting replicated. Texas, Europe, a few other places, and now Massachusetts.
Compliance With Recommended Food Safety Practices in Television Cooking Shows
Nancy Cohen, Rita Olsen
Journal of Nutrition Education and Behavior, 2016 Aug 28. pii: S1499-4046(16)30715-1. doi: 10.1016/j.jneb.2016.08.002. [Epub ahead of print]
Objective
Examine compliance with recommended food safety practices in television cooking shows.
Methods
Using a tool based on the Massachusetts Food Establishment Inspection Report, raters examined 39 episodes from 10 television cooking shows.
Results
Chefs demonstrated conformance with good retail practices for proper use and storage of utensils in 78% of episodes; preventing contamination (62%), and fingernail care (82%). However, 50% to 88% of episodes were found to be out of compliance with other personal hygiene practices, proper use of gloves and barriers (85% to 100%), and maintaining proper time and temperature controls (93%). Over 90% failed to conform to recommendations regarding preventing contamination through wiping cloths and washing produce. In only 13% of episodes were food safety practices mentioned.
Conclusions and Implications
There appears to be little attention to food safety during most cooking shows. Celebrity and competing chefs have the opportunity to model and teach good food safety practices for millions of viewers.
Consumers receive information on food preparation from a variety of sources. Numerous studies conducted over the past six years demonstrate that television is one of the primary sources for North Americans. This research reports on an examination and categorization of messages that television food and cooking programs provide to viewers about preparing food safely. During June 2002 and 2003, television food and cooking programs were recorded and reviewed, using a defined list of food safety practices based on criteria established by Food Safety Network researchers. Most surveyed programs were shown on Food Network Canada, a specialty cable channel. On average, 30 percent of the programs viewed were produced in Canada, with the remainder produced in the United States or United Kingdom. Sixty hours of content analysis revealed that the programs contained a total of 916 poor food-handling incidents. When negative food handling behaviors were compared to positive food handling behaviors, it was found that for each positive food handling behavior observed, 13 negative behaviors were observed. Common food safety errors included a lack of hand washing, cross-contamination and time-temperature violations. While television food and cooking programs are an entertainment source, there is an opportunity to improve their content so as to promote safe food handling.
Yesterday, Stockton Council decided to prosecute Robinsons.
David Huntley of Gazette Live reports Janet Bell and Trevor Robinson, of Robinsons Butchers, are due to appear at Teesside Magistrates’ Court today charged with food safety and hygiene breaches.
A previous report by Public Health England’s outbreak control team stated the likely cause of the outbreak was cross-contamination from raw meat to ready–to-eat food at Robinsons’ Billingham branch and “to a lesser degree” at the Wingate branch.
The authority has now mounted a prosecution against Robinson, 53, and Bell, 55.
Bell and Robinson are accused of breaching food hygiene rules at the Billingham shop by selling cooked ham, pork, beef and ham and egg quiche that was “unfit for human consumption” due to contamination by “pathogenic microorganisms.”
The offences are alleged to have taken place between July 2 and 20 last year.
Of the 15 people affected in the E. coli outbreak, 10 needed hospital treatment of which seven went on to develop hemolytic uremic syndrome, a serious condition affecting the kidneys.
All have since recovered.
One victim was Tia Donaldson who suffered kidney failure aged 11.
The youngster’s mum Rachael Donaldson, a volunteer from Billingham, told The Gazette in August last year that Tia was left in a critical condition after a series of strokes stemming from the poisoning.
Rachael said: “She’s had bleeds to her brain. On one occasion she couldn’t feel her left side.
“I was sat right next to her and she kept saying ‘please get my mum, you’re not my mum’.
When I meet someone who asks what I do the conversation usually turns to restaurant grades, foods I avoid and the famed 5-second rule. Most have an opinion that confirms their actions (where benefit may outweigh risk depending on what was dropped).
Paul Dawson and colleagues looked at the five-second rule in 2007 showing greater transfer with longer drying times with an 8 hour drying period of the floor contaminant. In 2014 a group of students at Aston University in Birmingham, U.K conducted some science-fair type experiments and reported the non peer-reviewed research on their university website. It got picked up all over the place and for 15 minutes the question was answered; everyone could go back to dropping their food on the floor and setting the critical limit at <5 seconds.
Rutgers graduate student Robyn Miranda and friend of barfblog (and podcast co-host extraordinaire) Don Schaffner tackled the 5-second rule in a more systematic way and put out a press release today after the paper went through peer-review and was published (cuz that’s how Schaffner rolls). The quick answer to whether the oft-cited risk prevention step is a myth? ‘The five-second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food. Bacteria can contaminate instantaneously.’
Turns out bacteria may transfer to candy that has fallen on the floor no matter how fast you pick it up.
Rutgers researchers have disproven the widely accepted notion that it’s OK to scoop up food and eat it within a “safe” five-second window. Donald Schaffner, professor and extension specialist in food science, found that moisture, type of surface and contact time all contribute to cross-contamination. In some instances, the transfer begins in less than one second. Their findings appear online in the American Society for Microbiology’s journal, Applied and Environmental Microbiology.
“The popular notion of the ‘five-second rule’ is that food dropped on the floor, but picked up quickly, is safe to eat because bacteria need time to transfer,” Schaffner said, adding that while the pop culture “rule” has been featured by at least two TV programs, research in peer-reviewed journals is limited.
“We decided to look into this because the practice is so widespread. The topic might appear ‘light’ but we wanted our results backed by solid science,” said Schaffner, who conducted research with Robyn Miranda, a graduate student in his laboratory at the School of Environmental and Biological Sciences, Rutgers University-New Brunswick.
The researchers tested four surfaces – stainless steel, ceramic tile, wood and carpet – and four different foods (watermelon, bread, bread and butter, and gummy candy). They also looked at four different contact times – less than one second, five, 30 and 300 seconds. They used two media – tryptic soy broth or peptone buffer – to grow Enterobacter aerogenes, a nonpathogenic “cousin” of Salmonella naturally occurring in the human digestive system.
Transfer scenarios were evaluated for each surface type, food type, contact time and bacterial prep; surfaces were inoculated with bacteria and allowed to completely dry before food samples were dropped and left to remain for specified periods. All totaled 128 scenarios were replicated 20 times each, yielding 2,560 measurements. Post-transfer surface and food samples were analyzed for contamination.
Not surprisingly, watermelon had the most contamination, gummy candy the least. “Transfer of bacteria from surfaces to food appears to be affected most by moisture,” Schaffner said. “Bacteria don’t have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer. Also, longer food contact times usually result in the transfer of more bacteria from each surface to food.”
Perhaps unexpectedly, carpet has very low transfer rates compared with those of tile and stainless steel, whereas transfer from wood is more variable. “The topography of the surface and food seem to play an important role in bacterial transfer,” Schaffner said.
So while the researchers demonstrate that the five-second rule is “real” in the sense that longer contact time results in more bacterial transfer, it also shows other factors, including the nature of the food and the surface it falls on, are of equal or greater importance.
“The five-second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food,” Schaffner said. “Bacteria can contaminate instantaneously.”
WORLD: Longer contact times increase cross-contamination of Enterobacter aerogenes from surfaces to food
02.sep.16 Appl. Environ. Microbiol. DOI: 10.1128/AEM.01838-16
Robyn C. Miranda and Donald W. Schaffner
Bacterial cross-contamination from surfaces to food can contribute to foodborne disease. The cross-contamination rate of Enterobacter aerogenes was evaluated on household surfaces using scenarios that differed by surface type, food type, contact time (<1, 5, 30 and 300 s), and inoculum matrix (tryptic soy broth or peptone buffer). The surfaces used were stainless steel, tile, wood and carpet. The food types were watermelon, bread, bread with butter and gummy candy. Surfaces (25 cm2) were spot inoculated with 1 ml of inoculum and allowed to dry for 5 h, yielding an approximate concentration of 107 CFU/surface. Foods (with 16 cm2 contact area) were dropped on the surfaces from a height of 12.5 cm and left to rest as appropriate. Post transfer surfaces and foods were placed in sterile filter bags and homogenized or massaged, diluted and plated on tryptic soy agar. The transfer rate was quantified as the log % transfer from the surface to the food. Contact time, food and surface type all had a highly significant effect (P<0.000001) on log % transfer of bacteria. The inoculum matrix (TSB or peptone buffer) also had a significant effect on transfer (P = 0.013), and most interaction terms were significant. More bacteria transferred to watermelon (~0.2-97%) relative to other foods, while fewer bacteria transferred to gummy candy (~0.1-62%). Transfer of bacteria to bread (~0.02-94%) and bread with butter (~0.02-82%) were similar, and transfer rates under a given set of condition were more variable compared with watermelon and gummy candy.
Four inoculated surrogate: uninoculated product weight ratios (10:100, 5:100, 1:100, and 0.5:100) and three inoculation levels (103, 101, and 10−1 CFU/g) were used for the three commodities. For each of three trials per condition, 5-kg batches containing uninoculated product and spot-inoculated surrogate products at each ratio and inoculation level were washed for 90 s in a 3.6-m-long flume tank through which 890 L of sanitizer-free, filtered tap water was circulated. After washing and removing the inoculated surrogate products, washed product (∼23, 225-g samples per trial) was analyzed for presence or absence of Salmonella Typhimurium or E. coli O157:H7 by using the GeneQuence Assay.
