Aussies getting the thermometer message; when will the Brits?

Posted on December 5, 2014 by Douglas Powell

ABC News Australia reports that chicken is Australia’s favorite meat.

The story goes with the just-cook-it-approach and ignores cross-contamination (isn’t there a better term? I say be the bug, but there’s lots of marketing geniuses out there), but at least Dr Duncan Craig, the principal microbiologist with Food Standards Australia New Zealand (FSANZ), says, “It’s about making sure that the center of the poultry meat gets up to a high enough temperature that would kill off the Campylobacter. So the advice that we put out is that the temperature should be up around 75 degrees [on the inside],” Craig says.

The best way to test whether poultry has been cooked to the right temperature is to use a meat thermometer; Craig says this is especially the case when you’re cooking a large bird such as a turkey.

“I was a skeptic but I use one at home and it actually is really quite effective, and on the converse it saves you from over cooking the poultry, just as much as making sure it’s cooked properly,” Craig says.

Someone’s been reading my soundbites – or not – but it’s gratifying to see the Aussies gravitate towards evidence-based advice, rather than what the Brits offer up: juices run clear and piping hot.

In the past, Food Standards Australia and New Zealand has found 84 per cent of chicken carcasses tested positive to Campylobacter (22 per cent tested positive to salmonella, another common cause of food poisoning).

Regarding cross-contamination, Dr. Craig says, “I’ve rescued a number of mates who have brought out the plate of marinated chicken skewers and popped them on the barbie. They then cook them to within an inch of their life and go to put them back on the plate, which had the raw chicken meat and the marinade on it.”

UK supermarkets named and shamed over Campylobacter on chicken contamination

Posted on December 3, 2014 by Douglas Powell

The UK Food Standards Agency (FSA) has published the cumulative results from the first two quarters of its year-long survey of campylobacter on fresh chickens.

Individual results by major retailer have also been published.

Retailers aren’t happy.

One of the companies that has helped develop a way to flash freeze the surface of birds to kill campylobacter bacteria after slaughter, Bernard Matthews, said that retailers had been resistant to the extra cost, which is about 4-5p per bird.

However, the Co-op, Marks & Spencer, Asda and Sainsbury’s all told the Guardian they were supporting the trials of technology which rapidly chills or steams the surface of a chicken to significantly reduce levels of campylobacter.

Tesco said it would be helping to fund a full-scale trial of rapid chill technology with one of its suppliers from January to test feasibility on a commercial scale.

Andrew Large, chief executive of the British Poultry Council, which represents the largest producers and processors, said the industry was focusing on about 10 measures that looked promising, but he warned that there was “no silver bullet” to end campylobacter contamination.

The results to date show:

18% of chickens tested positive for campylobacter above the highest level of contamination

70% of chickens tested positive for the presence of campylobacter

6% of packaging tested positive for the presence of campylobacter with only one sample at the highest level of contamination (>1,000 cfu/g)

* Above 1,000 colony forming units per gram (>1,000 cfu/g). These units indicate the degree of contamination on each sample.

In total, 1,995 samples of fresh whole chilled chickens have now been tested, with packaging also tested for most of these samples. Data show variations between retailers but none are meeting the end-of-production target for reducing campylobacter.

This 12-month survey, running from February 2014 to February 2015, will test 4,000 samples of whole chickens bought from UK retail outlets and smaller independent stores and butchers.

Campylobacter is killed by thorough cooking; however it is the most common form of food poisoning in the UK, affecting an estimated 280,000 people a year. Poultry is the source of the majority of these cases.

But-just-cook-it doesn’t cut it and fails to account for cross-contamination.

In response, a number of retailers have introduced ‘roast in the bag’ chickens which help limit cross-contamination by minimizing the handling of the raw chicken in the home.

The FSA advises that the data for individual retailers have to be interpreted carefully. Confidence intervals are given for each retailer and the ‘others’ category. These show the likely range of the results allowing for the number of samples taken.

At this half-way stage in the survey the results show, taking the confidence intervals into account, that Tesco is the only one of the main retailers which has a lower incidence of chicken contaminated with campylobacter at the highest level (>1,000 cfu/g), compared to the industry average. Asda is the only main retailer which has a higher incidence of chicken that is contaminated by campylobacter at the highest level, compared to the industry average. However, the results suggest that none of the retailers is achieving the joint industry end-of-production target for reducing campylobacter.

And what FSA chicken advice would be complete without a recommendation to “make sure chicken is steaming hot all the way through before serving. Cut in to the thickest part of the meat and check that it is steaming hot with no pink meat and that the juices run clear.”

This is ridiculous advice from a supposedly science-based agency: use a tip-sensitive digital thermometer.

Meanwhile, The Guardian revealed this week that Tim Smith, the former boss of the FSA who left the regulator to become a director of Tesco, is said to have contacted a senior official in the Department of Health in June to warn that the FSA’s plans could provoke a major food scare, in an apparent breach of the terms approved by David Cameron for his move to industry.

And Tim Lang, a professor of food policy at London’s City University, told The Guardian the results are schocking and that “public should refuse to buy poultry until this is sorted out. This is a public health scandal easily on a par to those of the 1980s and 1990s and reminds me of the outrage over food adulteration and contamination in the mid 19th century. Have we really sunk back to that level?”

Dear British public, be outraged, act, withhold your money until you can have confidence in what you consume. This may not be orthodox public health strategy but it is definitely what history shows works when standards are as dire as these results show them to be.

Blame it on the (chicken) juice — enhances surface attachment and biofilm formation of Campylobacter

Posted on October 21, 2014 by Douglas Powell

We were having dinner with friends Sunday night, and they do a Chinese-style cooking that is light and yummy, but I noticed a lot of cross-contamination going on during the prep (can someone please come up with a better name than cross-contaminaion, and more succinct than, dangerous bugs move around a lot).

The patron said, that’s why you cook it, and I said, just cook it doesn’t cut it, and explained why.

We may never be invited for dinner again.

The next day (another school holiday) the two 5-years-olds were with me for a few hours, so after a couple of hours at the park, I decided we would make two cakes — one gluten/dairy free, one traditional.

I don’t like cake but it is a part of my spring ritual of getting rid of spices that have accumulated for six years and, like Ikea furniture, crap that looked good at the store but awful at home.

The girls became involved in an extended discussion of Salmonella, eggs and cross-contamination.

They enjoyed the cake.

Brown et al. published in Applied and Environmental Microbiology that the bacterial pathogen Campylobacter jejuni is primarily transmitted via the consumption of contaminated foodstuffs, especially poultry meat. In food processing environments, C. jejuni is required to survive a multitude of stresses and requires the use of specific survival mechanisms, such as biofilms. An initial step in biofilm formation is bacterial attachment to a surface.

Here, we investigated the effects of a chicken meat exudate (chicken juice) on C. jejuni surface attachment and biofilm formation. Supplementation of brucella broth with ≥5% chicken juice resulted in increased biofilm formation on glass, polystyrene, and stainless steel surfaces with four C. jejuni isolates and one C. coli isolate in both microaerobic and aerobic conditions. When incubated with chicken juice, C. jejuni was both able to grow and form biofilms in static cultures in aerobic conditions. Electron microscopy showed that C. jejuni cells were associated with chicken juice particulates attached to the abiotic surface rather than the surface itself.

This suggests that chicken juice contributes to C. jejuni biofilm formation by covering and conditioning the abiotic surface and is a source of nutrients. Chicken juice was able to complement the reduction in biofilm formation of an aflagellated mutant of C. jejuni, indicating that chicken juice may support food chain transmission of isolates with lowered motility. We provide here a useful model for studying the interaction of C. jejuni biofilms in food chain-relevant conditions and also show a possible mechanism for C. jejuni cell attachment and biofilm initiation on abiotic surfaces within the food chain.

Helen L. Brown, Mark Reuter, Louise J. Salt, Kathryn L. Cross, Roy P. Betts, and Arnoud H. M. van Vliet

http://aem.asm.org/content/80/22/7053.abstract?etocjejuni

I’ve been everywhere: Norovirus transmission between hands, gloves, utensils, and fresh produce during simulated food handling

Posted on August 16, 2014 by Douglas Powell

Human noroviruses (HuNoVs), a leading cause of food-borne gastroenteritis worldwide, are easily transferred via ready-to-eat (RTE) foods, often prepared by infected food handlers.

In this study, the transmission of HuNoV and murine norovirus (MuNoV) from virus-contaminated hands to latex gloves during gloving, as well as from virus-contaminated donor surfaces to recipient surfaces after simulated preparation of cucumber sandwiches, was inspected. Virus transfer was investigated by swabbing with polyester swabs, followed by nucleic acid extraction from the swabs with a commercial kit and quantitative reverse transcription-PCR.

During gloving, transfer of MuNoV dried on the hand was observed 10/12 times. HuNoV, dried on latex gloves, was disseminated to clean pairs of gloves 10/12 times, whereas HuNoV without drying was disseminated 11/12 times. In the sandwich-preparing simulation, both viruses were transferred repeatedly to the first recipient surface (left hand, cucumber, and knife) during the preparation. Both MuNoV and HuNoV were transferred more efficiently from latex gloves to cucumbers (1.2% ± 0.6% and 1.5% ± 1.9%) than vice versa (0.7% ± 0.5% and 0.5% ± 0.4%). We estimated that transfer of at least one infective HuNoV from contaminated hands to the sandwich prepared was likely to occur if the hands of the food handler contained 3 log10 or more HuNoVs before gloving. Virus-contaminated gloves were estimated to transfer HuNoV to the food servings more efficiently than a single contaminated cucumber during handling. Our results indicate that virus-free food ingredients and good hand hygiene are needed to prevent HuNoV contamination of RTE foods.

American Society for Microbiology, Applied and Environmental Microbiology, Volume 80, No. 17, Septemper 2014, doi: 10.1128/AEM.01162-14

M. Rönnqvista, E. Ahoa, A. Mikkeläb, J. Rantab, P. Tuominenb, M. Rättöc and L. Maunulaa

http://aem.asm.org/content/80/17/5403.abstract?etoc

22 sickened: E coli outbreak at Scotland’s Hydro ’caused by under-cooked burgers’ at venue

Posted on July 3, 2014 by Douglas Powell

“We wish to assure the public that at this time we have no significant concerns in relation to catering for our patrons.”

That was the statement from SSE Hydro arena in Glasgow as the number stricken by E. coli O157 climbed in Feb. 2014.

Eventually at least 22 people were stricken, and a new report concludes it was due to under-cooking of beef burgers at the venue.

Of the 22 confirmed cases, a total of 19 of those cases attended had eaten beef burgers at the SSE Hydro’s food stall, Big Grill, between Friday 17 and Sunday 19 January 2014.

The remaining three individuals were infected after having household contact with the initial cases.

An investigation by NHS Greater Glasgow and Clyde (NHSGGC) alongside other public health bodies found evidence “strongly suggesting processing errors leading to under-cooking as well as the potential for cross contamination” at The Hydro.

The report concluded: “Descriptive evidence gathered by environmental health officers strongly suggests processing errors leading to under-cooking as well as the potential for cross contamination in the preparation and serving of the beef burger products.

“These processing errors would provide plausible mechanisms for exposure to VTEC (a strain of E coli).”

Health inspectors then visited the popular music venue after reports of the infection to examine how food was prepared by staff.

They found that preparation of food at “The Big Grill” at the venue involved a lack of consistency in the searing and cooking process of burgers.

Inspectors observed inadequacy of temperature monitoring records and weaknesses in temperature monitoring of food to test how cooked items were by staff.

It was also discovered there was “an inappropriate cleaning and disinfection regime, and an absence of documented evidence of a hazard analysis” at the venue.

All of the 19 confirmed primary cases had eaten a six ounce burger served on a bread bun from the Big Grill stall.”

Is there a better name for cross-contamination: kitchen cutting boards remain a source of multidrug-resistant bacteria after use

Posted on April 13, 2014 by Douglas Powell

After handling raw poultry, hands of food preparers and cutting boards remain a source of transmission for multi-drug resistant bacteria, such as E. coli that produce extended-spectrum beta-lactamases (ESBLs). The study of household and hospital kitchens was published in the May issue of the journal Infection Control and Hospital Epidemiology.

“The spread of multidrug-resistant bacteria has been associated with the hospital setting, but these findings suggest that transmission of drug-resistant E. coli occurs both in the hospital and households,” says Andreas Widmer, MD, lead author of the study. “Our findings emphasize the importance of hand hygiene, not only after handling raw poultry, but also after contact with cutting boards used in poultry preparation.”

Researchers from University Hospital in Basel, Switzerland collected and examined 298 cutting boards (154 from University Hospital and 144 from private households) after preparation of various meats (i.e., poultry, beef/veal, pork, lamb, game and fish) and before being cleaned. They also collected 20 pairs of gloves from hospital kitchen employees after they handled raw poultry. These samples were tested for the presence of ESBL-producing Enterobacteriaceae, a family of gram-negative bacteria that includes Salmonella, E. coli and Klebsiella.

In testing the cutting boards, researchers found that 6.5 percent of hospital cutting boards used in preparation of poultry were contaminated with ESBL-producing E. coli. For boards used in households, researchers found ESBL-producing E. coli on 3.5 percent of these surfaces. They also found that 50 percent of the hospital kitchen gloves were contaminated with this drug-resistant E. coli.

The researchers found that none of the cutting boards used in preparing beef/veal, pork, lamb, game or fish were contaminated with any ESBL-producing bacteria. They also found that the meat’s country of origin did not play a factor in the presence of bacteria on any of the surfaces.

Reference: Sarah Tschudin-Sutter, Reno Frei, Roger Stephan, Herbert Hächler, Danica Nogarth and Andreas F. Widmer. “Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae – a threat from the kitchen.” Infection Control and Hospital Epidemiology [35:5] (May 2014).

Source: Society for Healthcare Epidemiology of America (SHEA)

Campylobacter cases spike in NZ; cross-contamination fingered

Posted on February 21, 2014 by Douglas Powell

A spike in the number of people struck down by a foodborne illness in the MidCentral District Health Board region is most likely the result of cross contamination from poultry meat.

New figures from the Institute of Environmental Science and Research for December show a high number of campylobacteriosis cases, with 49 notified in the MidCentral region.

It is a significant increase compared to previous months, which typically have about 20 to 30 cases.

Massey University Infectious Disease Research Centre director Nigel French said the “urban campylobacter season” was in full swing and was generally when most cases of cross contamination from poultry meat occurred. “There are a whole lot of possible reasons why you might see an increase but November to February is the time when you see most cases of campylobacteriosis in urban areas,” he said.

“In rural areas you tend to see more cases in spring, particularly associated with calving season.”

Groundhog Day: UK cheese destroyed due to E. coli risk

Posted on January 28, 2014 by Douglas Powell

In 1996, 23 people died in an E. coli O157 outbreak when Scotland’s former butcher-of-the-year used the same knives on raw and cooked beef.

In 2005, a five-year-old child died and 160 were sickened after a butcher used the same vacuum packaging machine on raw and cooked beef.

Celebrity chef Marcus Wareing, who cooked for the Queen on her 80th birthday and is star of BBC’s Great British Menu series, failed his most recent restaurant inspection because he used the same vac-pak machine on raw and cooked product.

Now, according to the Cheddar Valley Gazette, cheese from Bridgwater Butchers has been seized and destroyed as a result of a routine food hygiene inspection carried out by Sedgemoor District Council Environmental Health staff on January 15.

Environmental health staff discovered that cheese from A I Foster’s, in St Marys Street, Bridgwater was being vacuum-packed on the same equipment as raw meat before being displayed for sale.

Due to the risk of the cheese being contaminated with E. coli O157 the cheese was seized.

An application was made to Taunton Magistrates Court by Sedgemoor’s Legal team for a condemnation order.

In addition to the costs of destroying the cheese the Council were also awarded full costs claimed of over £600.

The Food Standards Agency stress that: “Under no circumstances should it be considered safe to use the same complex equipment, such as vacuum packing machines, slicers, mincers, etc, for both raw and ready-to-eat foods.”

Rules need enforcement.

Perceptions, behaviors and kitchen hygiene of people who have and have not suffered campylobacteriosis: a case study

Posted on January 25, 2014 by Douglas Powell

I usually say, those that have knowingly had foodborne illness are more likely to pay attention to restaurant inspection data, be more attentive shoppers and take extra care at home.

Maybe I’ve been talking out my ass.

Or maybe not; it’s hard to know based on the results of a small-scale UK study.

Researchers looked at self-reported kitchen behaviors and perceptions (surveys still suck) of people who have had campylobacteriosis in comparison to people who have not had food poisoning. It also investigates microbiological kitchen hygiene within a smaller sample.

Follow-up surveys were done six months later and found that individuals who had not had food poisoning increased their optimism: it’s risk perception 101; things didn’t go bad yesterday so there’s a better chance things won’t go bad today.

And, as usual, there was a call for more effective food safety communication. No tips on how to do that.

Abstract

Whilst the scale of food poisoning in the home is not fully understood, the increase in sporadic cases of Campylobacter continues to place focus on home hygiene and domestic food safety practices. Domestic hygiene has rarely been identified as a risk factor for the incidence of campylobacteriosis but due to the high levels of sporadic cases of Campylobacter, cross contamination from kitchen practices remains of significant interest. Due to the complexities of human nature, finding the true risk perceptions and practices that take place in the kitchen is challenging, with social desirability bias affecting the results of surveys and optimistic bias influencing risk perceptions. This study looks at self-reported kitchen behaviours and perceptions of people who have had campylobacteriosis in comparison to people who have not had food poisoning. It also investigates microbiological kitchen hygiene within a smaller sample. The survey crucially includes a longitudinal element to investigate any change that may take place after a period of six months has elapsed. Optimistic bias was evident in both groups and no significant difference in perception was noted in the baseline study. However, the longitudinal study showed that individuals who had not had food poisoning increased their optimism, introducing a significant difference in optimistic bias between the two groups after six months had elapsed. Self-reported kitchen behaviours also exhibited a difference between the two groups, with the individuals who had campylobacteriosis responding more favourably with the exception of washing chicken and washing salad leaves sold in a bag. No evidence of kitchen hygiene differences could be found between the people who had suffered campylobacteriosis in comparison to people who had not had food poisoning. The results of the survey demonstrate that more effective food safety communication is required. Important messages such as ‘not washing chicken’ seem not to have been absorbed and the good practices become routine. These messages need particularly to be aimed towards people who may not perceive themselves as being at risk of getting food poisoning, such as the young, although the challenge of changing the practice of those who perceive themselves to be at low risk remains.

Food Control, Volume 41, July 2014, Pages 82–90

Caroline Millman, Dan Rigby, Gareth Edward-Jones, Lorraine Lighton, Davey Jones

Wet is better for bacteria; produce cross-contamination in the kitchen

Posted on September 4, 2013 by Douglas Powell

Rutgers food safety something Don Schaffner writes:

Every paper I’ve published has a history behind it. This one has its origins in Aberdeen Scotland in 2008.

Michelle Danyluk was a newly minted PhD out of Linda Harris’s lab at UC Davis and had just started as an assistant professor at the University of Florida. Like most good assistant professors Michelle was always on the lookout for grant opportunities, and she had recently seen a call for proposals from the U.S. Food and Drug Administration on consumer risk from fresh-cut produce. Michelle had offered to lead the grant writing efforts with Linda and I as co-principal investigators. The grant submission deadline fell during the Food Micro 2008 meeting in Aberdeen, Scotland and of course, as the deadline loomed closer, the proposal wasn’t finished. Michelle and I were in Scotland, and Linda was back in Davis, California. Fueled by Scottish Thai food (actually not that bad), and beer, as well as a passible Internet connection and the occasional trans-Atlantic phone call, the three of us hammered out the details of who would do what in the proposal. Somehow it all worked, and FDA decided to give us the money. And Michelle got tenure.

Three years later, the grant is mostly spent, and Michelle is sitting on a pile of data collected by super-technician Lorrie Friedrich. Michelle and Lorrie have amassed an astounding pile of cross-contamination data for four different surfaces (ceramic, stainless steel, glass, and plastic) and four types of fresh-cut produce (carrots, watermelon, celery and lettuce) under both dry and wet conditions, and considering transfer in either direction. Because Michelle was foolish enough to listen to me when I suggest we repeat each experiment 20 times to “capture inherent variability,” the entire dataset was composed of more than 600 observations. Enter graduate student Dane Jensen.

Dane is from the Jersey shore. The real Jersey shore, near Asbury Park. I pointed Dane at the pile of data and told him to come back when it was graphed and analyzed. He did a good job, and it was part of his Masters thesis, and our recent publication in the Journal of Food Protection.

What did we discover when we set off down this road in Aberdeen? Mostly that surface moisture and direction of transfer have the greatest influence on microbial transfer rates: bacteria would rather be on a wet produce surface than a dry counter-top or cutting board. Want to learn more? Order up some Thai food, crack open a beer and read the article.

Quantifying transfer rates of Salmonella and Escherichia coli O157:H7 between fresh-cut produce and common kitchen surfaces

Journal of Food Protection®, Number 9, January 2013, pp. 1488-1657, pp. 1530-1538(9), DOI: http://dx.doi.org/10.4315/0362-028X.JFP-13-098

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

http://www.ingentaconnect.com/content/iafp/jfp/2013/00000076/00000009/art00005

Abstract:

Cross-contamination between foods and surfaces in food processing environments and home kitchens may play a significant role in foodborne disease transmission. This study quantifies the cross-contamination rates between a variety of fresh-cut produce and common kitchen surfaces (ceramic, stainless steel, glass, and plastic) using scenarios that differ by cross-contamination direction, surface type, produce type, and drying time/moisture level. A five-strain cocktail of rifampin-resistant Salmonella was used in transfer scenarios involving celery, carrot, and watermelon, and a five-strain cocktail of rifampin-resistant Escherichia coli O157:H7 was used in transfer scenarios involving lettuce. Produce or surface coupons were placed in buffer-filled filter bags and homogenized or massaged, respectively, to recover cells. The resulting solutions were serially diluted in 0.1% peptone and surface plated onto tryptic soy agar with 80 μg/ml rifampin and bismuth sulfite agar with 80 μg/ml rifampin for Salmonella or sorbitol MacConkey agar with 80 μg/ml rifampin for E. coli O157:H7. When the food contact surface was freshly inoculated, a high amount (>90%) of the inoculum was almost always transferred to the cut produce item. If the inoculated food contact surfaces were allowed to dry for 1 h, median transfer was generally >90% for carrots and watermelon but ranged from <1 to ∼70% for celery and lettuce. Freshly inoculated celery or lettuce transferred more bacteria (<2 to ∼25% of the inoculum) compared with freshly inoculated carrots or watermelon (approximately <1 to 8%). After 1 h of drying, the rate of transfer from inoculated celery, carrot, and lettuce was <0.01 to ∼5% and <1 to ∼5% for watermelon. Surface moisture and direction of transfer have the greatest influence on microbial transfer rates.

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