NZ says (not a joke): Have your say on cooking burgers: Until a chef offers a temperature rather than adjectives it’s bullshit

While Australia is being dragged kickin-and-screamin into the thermometer age, New Zealand has decided to put knowledge aside, and ask the people, How do you want your burgers done?

Just because everyone eats doesn’t mean they know anything about microbial food safety.

The NZ Ministry for Primary Industries issued a public notice, stating: Feedback from chefs is that they would like to be able to cook mince (especially minced burger patties) to medium/medium rare (I have no idea what these adjectives mean; some numbers, please) under the template food control plan.

MPI has worked with chefs, environmental health offers and food scientists to develop a specialist section for both official template food control plans.  The specialist page is written in the “Know, Do, Show” format from the Simply Safe & Suitable template. The section will allow red meat mince for medium/medium rare burgers, and other meat specialities like steak tartare, to be safely served lightly cooked or raw. (Carpaccio is already covered in the templates (refer to section 10.6 (Serve) –  Whole cuts and whole joints of meat – and the ‘Cooking food’ page in Simply Safe & Suitable).

We want to know if the specialist section works for you? Have we got it right?  

Please note: Two of the processes included in the consultation are sanitising and blanch-in-a-bag.  The scientific validation for these methods is ongoing.  If there is insufficient evidence for it to be included in this amendment for the official template food control plans, and there is high demand for the process, further research would need to be commissioned so it could be added at a later date.

The consultation opens 25 July and closes on 8 August 2017.

Email your feedback to foodact.2014@mpi.govt.nz

I suggest e-mailing them this blog post and saying, I want a burger cooked safely to a verified 74C.

Levine writes: Investigating shoppers’ perceptions of risk

Katrina Levine, extension associate and lead author of Consumer perceptions of the safety of ready-to-eat foods in retail food store settings writes,

While I was grocery shopping one day at my regular store, I noticed that one of the doors to the dairy refrigerator case was missing. There was no sign or notice to explain the gaping hole where the door should have been in front of the shredded cheese, nor was any attempt made to compensate for the absent door, such as by relocating the items in that section or putting up a temporary covering.

After first being a bit confused when trying to reach for a non-existent handle, these questions popped into my head:

• how can the food in this section be at a safe temperature, as well as the foods on either side of it? and,

• doesn’t this missing door affect the ability of the case to maintain its temperature?

I’m a food safety nerd. Most people just want to shop and get on with whatever they are doing, but I’m subconsciously always looking for food safety behaviors. The person standing behind me was probably more interested in which brand was the least expensive or which package looked the freshest, or just wanted me to get out the way so they could buy their cheese and leave.

Does the lack of a door on a normally enclosed refrigerator case pose a food safety risk for dairy the products in that case? Depends on whom you ask. The average consumer (interpret this as you choose) often doesn’t see the same food safety risks when shopping in grocery stores compared to food safety folks.

Our group from North Carolina State teamed up with John Luchansky and Anna Porto-Fett at the U.S. Department of Agriculture’s Agricultural Research Service to investigate this difference between consumers and food safety folks in food safety risk perception when shopping at grocery stores.  We conducted a national survey and several focus groups where, instead of just describing a situation, we showed pictures of a food safety situation someone could actually encounter while shopping. In addition to asking questions about whether each photo was safe or unsafe, we wanted to know about the actions, if any, people would take to do something about a situation they thought was unsafe. We prodded them further with questions about how their perceptions of safety would affect their shopping behaviors.

We found that consumers and food safety folks don’t always see the same food safety risks. There were some situations consumers perceived as risky but that weren’t actually risks, like seeing an insect on the floor. There were also some risks that food safety folks saw but consumers missed, like food not properly stored within the refrigerated area.

I was explaining our study to a friend the other day, and she flat out told me, “I look for food quality when I’m shopping – is it fresh, is there mold or signs of damage, does it look ok?” This is exactly what we found. Consumers are looking for those quality aspects, but aren’t always seeing the warning signs that the safety of the food could be at risk. The viruses, bacteria, and other things that cause foodborne illness such as Listeria monocytogenes, might be present on foods in the grocery store at high levels by not storing soft cheeses at the proper temperature, allowing bacteria to grow more quickly.

Our research team will be taking this one step further to better understand the mind of the shopper and see things through their eyes. Everyday consumers will become our secret shoppers, and we plan to arm them with the information they need to be food safety detectives every time they shop. #citizenscience for the win.

Consumer perceptions of the safety of ready-to-eat foods in retail food store settings

Katrina Levine, Mary Yavelak, John B. Luchansky, Anna C. S. Porto-Fett, and Benjamin Chapman

Journal of Food Protection

August 2017, Vol. 80, No. 8, pp. 1364-1377

DOI: doi.org/10.4315/0362-028X.JFP-16-417

Abstract:

To better understand how consumers perceive food safety risks in retail food store settings, a survey was administered to 1,041 nationally representative participants who evaluated possible food safety risks depicted in selected photographs and self-reported their perceptions, attitudes, and behaviors. Participants were shown 12 photographs taken at retail stores portraying either commonly perceived or actual food safety contributing factors, such as cross-contamination, product and equipment temperatures, worker hygiene, and/or store sanitation practices. Participants were then asked to specifically identify what they saw, comment as to whether what they saw was safe or unsafe, and articulate what actions they would take in response to these situations. In addition to the survey, focus groups were employed to supplement survey findings with qualitative data. Survey respondents identified risk factors for six of nine actual contributing factor photographs >50% of the time: poor produce storage sanitation (86%, n = 899), cross-contamination during meat slicing (72%, n = 750), bare-hand contact of ready-to-eat food in the deli area (67%, n = 698), separation of raw and ready-to-eat food in the seafood case (63%, n = 660), cross-contamination from serving utensils in the deli case (62%, n = 644), and incorrect product storage temperature (51%, n = 528). On a scale of 1 to 5, where 1 was very unsafe and 5 was very safe, a significant difference was found between average risk perception scores for photographs of actual contributing factors (score of ca. 2.5) and scores for photographs of perceived contributing factors (score of ca. 2.0). Themes from the focus groups supported the results of the survey and provided additional insight into consumer food safety risk perceptions. The results of this study inform communication interventions for consumers and retail food safety professionals aimed at improving hazard identification.

Thermometers, cats and the UK Food Standards Agency: Piping hot for the world?

I watched our veterinarian stick a thermometer into the ass of our cat(s) the other day while they were getting vaccinated for feline immunodeficiency virus (because they’ve now become outside roaming cats).

They didn’t care.

The UK Food Standards Agency is bragging that one of its own, Steve Wearne, got elected to the Codex Alimentarius Commission as vice-chair.

That’s an impressive bureaucratic achievement.

UK Food Minister George Eustice bubbled that, “The appointment of Steve Wearne to this important leadership role is testament to the strength and reputation of the UK’s food quality and safety standards. 

“This is a great opportunity to bring the UK’s renowned expertise to the table as the committee continues to pioneer global policy for food safety – increasing consumer confidence in the food we eat around the world.”

Heather Hancock, Chairman of the FSA said: ‘Steve’s appointment is a real vote of confidence in the UK’s leadership in modern, accountable food regulation. I’m delighted that he and the FSA will be taking such a significant role in setting the standards for food globally.’

I’m not.

This is an agency that ignores science and continues to tell consumers to cook things until they are piping hot, apparently because consumers are too low on the British caste system to understand how a thermometer works.

My cats know how thermometers work.

Use a fucking thermometer: Ireland says eating undercooked burgers ‘like driving without a seatbelt’

Diners who enjoy a juicy burger have been warned that eating them pink in the middle is “like driving without wearing a seatbelt”.

Fiachradh McDermott of The Irish Times reports that safefood began its new campaign, “Burger Fever”, on Thursday to inform people that eating undercooked burgers could lead to serious or sometimes life-threatening food poisoning.

What she didn’t report is that color is a terrible indicator of safety, and that needle-or-blade-tenderized steaks carry the same risk as mince, so this science-based agency is publishing fairy tales.

But I’ll let the bureaucrats speak for themselves and you judge.

The body advised people to always ask for burgers to be well-cooked in restaurants.

In an online survey conducted by safefood, 96 per cent of people considered themselves well-informed about food safety. However, 51 per cent admitted to eating undercooked burgers.

Two thirds of respondents said they would reconsider their choice if they knew there was a possibility of food poisoning.

Undercooked burgers carry the risk of E. coli, which can have long-term effects. The biggest worry is a type called VTEC, which causes severe diarrhoea.

Dr Linda Gordon, chief specialist in food science at safefood, said it can result in “frequent serious complications.” VTEC can affect the blood and kidneys, and is most serious in older people and children under five. However, it only takes as little as ten E. coli cells to make a person sick, she said.

Dr Gordon said the campaign is intended as a preventative measure, but “emphasising the difference between a burger and a steak” is an important aspect.

According to Dr Gary Kearney, director of food science at safefood, “Mince used in hamburgers is a higher risk as the food poisoning bacteria that live on the surface of the beef (steak) is then mixed through the middle of the burger when the beef is minced – so in effect, the outside is now on the inside.”

Dr Martin Cormican, Professor of Bacteriology at National University of Ireland, Galway (NUIG), emphasised the possibility and danger of contracting VTEC from undercooked meat.

“Eating burgers that are pink in the middle is a bit like driving without a seatbelt; you might get away with it for years but if something goes wrong and you are harmed, will you still think it was worth it?”

No mention of thermometer, cooking temps and hold times, just plain pandering.

Use a fucking thermometer and stick it in.

Assessment of risk communication about undercooked hamburgers by restaurant servers

E. Thomas, E,M,, Binder, A., McLaughlin, A., Jaykus, L., Hanson, D, Powell, D.A., Chapman, B. 2016.

Journal of Food Protection Vol. 79, No. 12, pp. 2113-2118

http://www.jfoodprotection.org/doi/abs/10.4315/0362-028X.JFP-16-065?code=fopr-site

According to the U.S. Food and Drug Administration 2013 Model Food Code, it is the duty of a food establishment to disclose and remind consumers of risk when ordering undercooked food such as ground beef.

The purpose of this study was to explore actual risk communication activities of food establishment servers. Secret shoppers visited restaurants (n=265) in seven geographic locations across the U.S., ordered medium rare burgers, and collected and coded risk information from chain and independent restaurant menus and from server responses.

The majority of servers reported an unreliable method of doneness (77%) or other incorrect information (66%) related to burger doneness and safety. These results indicate major gaps in server knowledge and risk communication, and the current risk communication language in the Model Food Code does not sufficiently fill these gaps. Furthermore, should servers even be acting as risk communicators? There are numerous challenges associated with this practice including high turnover rates, limited education, and the high stress environment based on pleasing a customer. If it is determined that servers should be risk communicators, food establishment staff should be adequately equipped with consumer advisory messages that are accurate, audience-appropriate, and delivered in a professional manner so as to help their customers make more informed food safety decisions.

Color sucks: Use a thermometer and stick it in for food safety

safefood Ireland has joined the UK Food Standards Agency in providing terrible advice about how to cook burgers.

A recipe for summer beef burgers (may a fine solstice greet our Northern and Southern friends) endorsed by safefood says:

“Before serving, ensure that the burgers are cooked thoroughly. Cut into them with a clean knife and check that they are piping hot all the way through, there is no pink meat remaining and that the juices run clear.”

Meanwhile, FSA issued a Safe Summer Food guide as UK picnickers head out in the sun (there’s sun in the UK?). The guidelines were in part based results of a self-reported survey, which is largely meaningless but something FSA likes to do.

The Morning Advertiser has more details on the hoops FSA seems willing to jump through to ensure the safety of rare burgers including:

  • sourcing the meat only from establishments which have specific controls in place to minimise the risk of contamination of meat intended to be eaten raw or lightly cooked;
  • ensuring that the supplier carries out appropriate testing of raw meat to check that their procedures for minimising contamination are working;
  • Strict temperature control to prevent growth of any bugs and appropriate preparation and cooking procedures;
  • notifying their local authority that burgers that aren’t thoroughly cooked are being served by the business; and,
  • providing advice to consumers, for example on menus, regarding the additional risk.

The advice from these self-proclaimed science-based agencies is at odds with, uh, science.

It has been known for over two decades that color is a lousy indicator of safety in hamburger.

The latest addition to this work comes from Djimsa et al. in the Dept. of Animal Science at Oklahoma State Univ., who wrote in the Journal of Food Science earlier this year that:

Premature browning is a condition wherein ground beef exhibits a well-done appearance before reaching the USDA recommended internal cooked meat temperature of 71.1 °C; however, the mechanism is unclear.

The objectives of this study were: (1) to determine the effects of packaging and temperature on metmyoglobin reducing activity (MRA) of cooked ground beef patties and (2) to assess the effects of temperature and pH on thermal stability of NADH-dependent reductase, lactate dehydrogenase (LDH), and oxymyoglobin (OxyMb) in-vitro.

Beef patties (lean: fat = 85:15) were packaged in high-oxygen modified atmosphere (HiOX-MAP) or vacuum (VP) and cooked to either 65 or 71 °C. Internal meat color and MRA of both raw and cooked patties were determined. Purified NADH-dependent reductase and LDH were used to determine the effects of pH and temperature on enzyme activity. MRA of cooked patties was temperature and packaging dependent (P < 0.05). Vacuum packaged patties cooked to 71 °C had greater (P < 0.05) MRA than HiOX-MAP counterparts.

Thermal stability of OxyMb, NADH-dependent reductase, and LDH were different and pH-dependent. LDH was able to generate NADH at 84 °C; whereas NADH-dependent reductase was least stable to heat.

The results suggest that patties have MRA at cooking temperatures, which can influence cooked meat color.

Effects of metmyoglobin reducing activity and thermal stability of NADH-dependent reductase and lactate dehydrogenase on premature browning in ground beef

Journal of Food Science, 2017 Feb, 82(2):304-313, doi: 10.1111/1750-3841.13606. Epub 2017 Jan 18.

https://www.ncbi.nlm.nih.gov/pubmed/28099768

Can consumers handle the truth (yes)? Can they handle potty-mouth (yes)? are auditors fucking robotrons when people die, from food (yes)

A subscriber from a third-party auditing company recently wrote and said I had a potty mouth.

I said get the fuck over it, nothing else seems to work, so try something different when it comes to food safety behavior.

You can go and get all hepped up on food safety culture, but it don’t translate into shit.

Night soil shit.

The kind that fertilizes all the veggies for the fancy restaurants in Melbourne, Sydney, Brisbane and around the globe.

Gregory Bloom asks in MeatingPlace, can consumers handle the truth?

Besides the tortured writing, the answer is, duh.

For the past 25 years, all I’ve heard is we can’t adopt new technology because consumers don’t want it.

Bullshit.

Consumers don’t know what they want until they are offered it.

We sorta proved that in 2000 when we offered genetically engineered and conventional sweet corn and potatoes for sale at a farmer’s market.

The big stores wouldn’t let us in, because they were terrified to let moms and dads know that sweet corn and potatoes was grown with pesticides.

Corporate assholes.

Which allowed the anti-GE crowd to come up with some conspiracy shit that resulted in a death-to-science banner on my lab door.

Move out of your parent’s basement, get a life.

Bruce Cran of the Consumers Association of Canada told CTV News the federal government has done “an incompetent job” informing Canadians that irradiation is safe and he worries that a lack of action could lead to a deadly outbreak.

“They need to promote an understanding so Canadians can make an informed choice, and they’re not doing that for whatever reason,” Cran said. “This is not only a safe practice, it’s one that many of us would like to be able to use.”

“Our members would absolutely support it,” said Robin Horel, president of the Canadian Poultry and Egg Processors Council.

“But we haven’t pushed hard because … the companies that produce chicken and turkey are concerned about what the consumer response would be.”

It’s called leadership.

Yes, leaders get some arrows in the back, but it’s been decades, either get behind science or suffer down the road.

My cousin the asparagus farmer bills his crop as genetically-engineered free. But anyone in the know knows that asparagus has been bred using multiple techniques over the years so it is absolutely genetically modified.

I asked him once if a fungal resistant GE asparagus came along, would he plant it.

He shrugged.

I have full respect for any farmer that can make a living doing whatever, getting gullible consumers to buy whatever.

There is a long history of food fairy tales, most famously linked to Dr. Kellogg in Michigan.

Anna Madison, a spokeswoman for Health Canada, said in an email the federal government would not promote irradiation since it does not engage in promotional activities.

Bullshit.

Health Canada promotes all kinds of bad food safety advice, from handwashing to thermometer use.

Rick Holley, professor emeritus of food microbiology and food safety at University of Manitoba, says irradiation is safe and is even more important for chicken than for ground beef. Chicken causes more illness in Canada, he said.

Holley said salmonella is naturally present on a lot of chicken and the gastro-intestinal bacteria campylobactor is present on all of it, regardless of whether a bird is free-range or factory.

“Both of these organisms occasionally kill, but because they make more people ill who recover, then the emphasis is not placed on them to the same extent as E. coli O157 in hamburger,” said Holley, who suggested that irradiating chicken could cut food-related illness in Canada by 25 per cent.

(Like my The Who T-shirt?)

 

Cooking pork to control Hep E: Use a fucking thermometer

In 1998, the U.S. Department of Agriculture very publicly began to urge consumers to use an accurate food thermometer when cooking ground beef patties because research demonstrated that the color of meat is not a reliable indicator of safety.

USDA Under Secretary for Food Safety at the time, Catherine Woteki, said, “Consumers need to know that the only way to be sure a ground beef patty is cooked to a high enough temperature to destroy any harmful bacteria that may be present is to use a thermometer.”

At the time, I said, no one uses a meat thermometer to check the doneness of hamburgers. The idea of picking up a hamburger patty with tongs and inserting the thermometer in sideways was too much effort (others insist the best way to use a tip sensitive digital thermometer is to insert into the middle of the patty at a 45 degree angle).

I was wrong.

Shortly thereafter, I started doing it and discovered, not only was using a meat thermometer fairly easy, it made me a better cook. No more extra well-done burgers to ensure the bugs that would make me sick were gone. They tasted better.

By May 2000, USDA launched a national consumer campaign to promote the use of food thermometers in the home. The campaign featured an infantile mascot called Thermy that proclaimed, “It’s Safe to Bite When the Temperature is Right.”

Seventeen years later, the converts are minimal. Canada came to the thermometer table a few years ago,  Australia is doing a slow policy creep, but the UK is still firmly committed to piping hot.

The UK Food Standards Agency recently published the sixth, chief scientific adviser’s Science Report, entitled Data Science. No mention of thermometers except to determine refrigerator temperatures or included as packing on food.

Science-based policy depends on whose science is being quoted to what ends. The fancy folks call it value judgments in risk assessments; Kevin Spacey in the TV series House of Cards would call it personal advancement.

So last week, when UK media reports dubbed Hepatitis E the Brexit virus, with the potential for 60,000 Brits to fall sick annually from EU pork, the UK Food Standards Agency once again reiterated how fucking unscientific they are.

“Following media reports this morning we wanted to remind consumers of our advice about cooking pork thoroughly. We always advise that whole cuts of pork, pork products and offal should be thoroughly cooked until steaming hot throughout, the meat is no longer pink and juices run clear.”

The National Pig Association — it’s a thing, “recommends that consumers follow the advice from the Food Standards Agency that pork and sausages should be cooked thoroughly until steaming hot throughout, with no pink or red in the centre, to greatly reduce the risk of infection.”

Back to science instead of a rainbow fairy tale on safe cooking procedures, in May 2011, USDA recommended pork, and all whole meat cuts, only have to get to 145 degrees internally, not the 160 the agency had previously suggested, followed by a 3-minute rest.

The U.S. pork board for years promoted pork be cooked with a “hint of pink.”

This has more to do with breeding efforts to produce leaner pork.

But HEV is a different beast.

Public Health England reported the number of severe cases has almost trebled since 2010, with 1,244 reported in 2016, compared with 368 six years earlier.

The virus causes a flu-like illness and in severe circumstances, could cause death.

This strain has been linked to pig farms in France, Holland, Germany and Denmark and is only killed in meat if people cook it for longer than usual.

Dr Harry Dalton, a gastroenterologist at Exeter University, told a conference on neurological infectious diseases HEV had become a major threat and that no one should eat pink pork and that pregnant women and transplant patients should not eat pork at all.

He also said the virus is heat resistant and survives being cooked until the meat is heated to above 71C (160F) for two minutes.

Looks like some research is required, not that the Brits would change their no pink policy. Maybe they’re homophoblic.

With Memorial Day on Monday in the U.S. and a bank holiday Monday in the U.K., whatever that is, USDA yesterday once again stated, “The best and only way to make sure bacteria have been killed and food is safe to eat is by cooking it to the correct internal temperature as measured by a food thermometer.”

Recent research by USDA and the Food and Drug Administration (FDA) found that only 34 percent of the public use a food thermometer when cooking hamburgers – and that’s self-reported, people lie on surveys.

Use a fucking thermometer and stick it in.

(If you don’t like profanity, don’t read, but if you want to read, your IT censors may figure you can’t handle such dreadful language, and messages are getting blocked. You may want to have a word with your IT folks.)

Our battle with Gwyneth: cookbook edition

The coverage of extension associate Katrina Levine’s research on cookbook food safety messages took an unexpected turn yesterday. Gwyneth Paltrow’s ‘people’ weighed in.

By ‘people’ I think it’s the folks who published her cookbooks.

It started with a string of emails from some folks in the UK who saw the NC State press release about the research. After analyzing 1700+ recipes from cookbooks on the New York Times best seller list we found that safe endpoint temperatures only appeared in just over 8% of the instructions.

Not great.

A few journalists want to know who are the biggest offenders are (quick answer: it’s pretty well everyone we looked at – but not all the time).

One of the books included in our study was Paltrow’s It’s All Good. In a flurry of questions, and without being able to find all the recipes online, I sent one of the enquiring minds a recipe from another book, My Father’s Daughter as an example of what we were looking at, with this note:

“Here’s one from chef Paltrow that does not have a safe endpoint temperature included (165F or 74C).

Heat oven to 400°. Mix butter, garlic salt, paprika, pepper and salt in a bowl. Rinse chicken inside and out; pat dry. Insert fingers between skin and breast to separate the two. Rub seasoned butter over chicken and under skin. Tuck wings underneath bird and tie together with a piece of twine. Tie legs together with another piece of twine. Place chicken on its side in a heavy roasting pan and roast 25 minutes. Turn onto its other side and sprinkle with several tbsp water; roast 25 minutes more. Turn chicken on its back; roast 10 minutes more. Turn on its breast; roast until skin is crispy and chicken is golden brown, 10 minutes more. Remove from pan and let rest, breast side down, 15 minutes, before carving (remove skin).”

The Paltrow folks responded, through the journalist with this:

“The recipe for “Roast Chicken, Rotisserie Style” was published in MY FATHER’S DAUGHTER in April 2011. While it did not have an endpoint temperature included, the directions called for the chicken to be roasted at 400F for 70 minutes, which is ample time to cook a 3-4 pound chicken.

IT’S ALL GOOD, which was published in April 2013, does include endpoint temperatures. “Super-Crispy Roast Chicken” in IT’S ALL GOOD is baked for 1-1/2 hours at 425 degrees and the recipe advises “The chicken thigh should register 165 degrees F on a digital thermometer at the very least (I usually let it get to 180 Degrees F just to be completely sure it’s cooked all the way through the bone).”

So we went back to the data – and yep, we noted that the Super-Crispy Roast Chicken had a safe end point temperature. What they omitted was that the first instruction in the recipe was to wash the chicken; one of the steps that can increase the risk of foodborne illnesses.

There were these other recipes from It’s All Good that don’t have the safe endpoint temperatures (and tell the reader to do non science-based things like touch it, look for clear juices or color to ensure doneness):

The row (I think that’s the correct colloquial British term) made the front page of the Daily Mail (above, exactly as shown).

As for this comment, ‘the directions called for the chicken to be roasted at 400F for 70 minutes, which is ample time to cook a 3-4 pound chicken.’

Maybe, show me the data. Lots of variables that can impact the final temperature – starting temperature of the chicken, thickness, oven heat calibration.

Isn’t it just easier to tell folks what the safe temperature is and tell them to stick it in?

Food and Wine points out exactly what we found. It’s not just Gwyneth.

But for once, let’s cut Paltrow some slack. Out of the whopping 29 best-selling cookbooks these experts analyzed, only nine percent of them included specific temperature information. She’s in good company. Meanwhile, only 89 — 89! — of the 1,497 recipes included in the study were deemed instructionally safe.

Honestly, none of this seems too egregious, and we almost wish Paltrow didn’t have to deal with the PR headache.

Oh well.

Leftover rice risks from Lifehacker

One of my former roommates was a straight edge punk-loving vegan for a while. Now he eats meat and drinks beer, but for a while he survived on rice and sriracha. Sometimes he left his steamed rice out overnight – making some egg-free fried rice the next day. This was before either of us knew much about Bacillus cereus and rice.

Earlier this week Claire Lower from Lifehacker emailed a couple of questions about leftover rice safety. The Lifehacker folks often ask really good questions about the science and why behind food safety recommendations – Claire included. Claire wanted to know why some guidelines say not to leave rice out on the stove over night.

I sent Claire a couple of papers including this one which is an oldie (1974), but a goodie from Gilbert and colleagues which included this awesome B. cereus spore/vegetative cell growth figure (right, exactly as shown) highlighting anincrease of a log or more within 4 hours once in vegetative state.

We looped Don into our discussion and he pointed out the somewhat common practice of boiled and then fried rice in some Asian cooking techniques.

According to Benjamin Chapman, Food Safety Specialist from North Carolina State University, cooking rice doesn’t necessarily kill all the pathogens that may be lurking about. “The issue with rice,” he explained to me over email, “is that one pathogen, Bacillus cereus, is quite prevalent in dried rice (some sources say ubiquitous), likely as spores. The spores may survive cooking. If cooked rice is subsequently held at room temperature, the spores can come out of their protective form, germinate, and vegetative forms multiply. The cooked rice environment provides a lot of water and nutrients for growth. As a by-product of growth, they create a couple of toxins, including a heat-stable one.”

Beyond refrigerating any home-cooked rice, a sense of vigilance is helpful when dining out. According to food scientist Donald Schaffner of Rutgers University, some restaurants “cook up a large batch of rice, hold it at room temperature all day,” and then take portions from the batch as needed. “Because Bacillus makes a heat stable toxin,” he explained “this is not a best practice, and has led to outbreaks in the past.” “Heat stable” means that the toxin can survive boiling and, once the rice is cooled into the “danger zone” of 59-122°F, the bacteria can multiply, making even more of the toxin. Sushi rice, he noted, shouldn’t be a problem as vinegar is added to lower the pH, allowing it to be held safely at room temperature.