Ben Chapman

About Ben Chapman

Dr. Ben Chapman is an associate professor and food safety extension specialist at North Carolina State University. As a teenager, a Saturday afternoon viewing of the classic cable movie, Outbreak, sparked his interest in pathogens and public health. With the goal of less foodborne illness, his group designs, implements, and evaluates food safety strategies, messages, and media from farm-to-fork. Through reality-based research, Chapman investigates behaviors and creates interventions aimed at amateur and professional food handlers, managers, and organizational decision-makers; the gate keepers of safe food. Ben co-hosts a biweekly podcast called Food Safety Talk and tries to further engage folks online through Instagram, Twitter, Facebook, YouTube and, maybe not surprisingly, Pinterest. Follow on Twitter @benjaminchapman.

FDA releases Romaine-linked outbreak report

Friends of the blog Scott Gottlieb and Frank Yiannas posted a statement to FDA’s website today detailing the findings of the agency’s investigation into over 50 E. coli O157 illnesses in the fall of 2018.

Today, we’re announcing the findings of this investigation and our best hypotheses as to how this contamination could have occurred. In the case of the one farm with a positive sample previously referenced, the FDA believes that the most likely way romaine lettuce on a specific ranch on this farm became contaminated was from the use of water from this reservoir as agricultural water. It is believed that this water came into contact with the harvested portion of the romaine lettuce, since the outbreak strain of E. coli O157:H7 was found in sediment from the reservoir and in no other sampled locations. The water from the reservoir doesn’t explain how lettuce grown on other ranches or farms identified by traceback may have been contaminated. So, this one farm cannot explain the entire outbreak.

The full report can be found here.

My favorite part is this recommendation from investigators:

Perform a root cause analysis when a foodborne pathogen is identified in the growing environment, in agricultural inputs (e.g., agricultural water or soil amendments), in raw agricultural commodities or in fresh-cut ready-to-eat produce. The goal of a root cause analysis is to determine the likely source of the contamination, if prevention measures have failed, and whether additional measures are needed to prevent a reoccurrence.

From my experience, this root cause analysis approach is hit or miss when pathogens are found during routine sampling (but maybe a barfblog reader can provide me with some details on whether they know of folks doing this).

Pressure cooking and pressure canning

My friend, PIO extraordinaire and around great guy Matt Shipman asked Natalie and I about electric pressure cookers a couple of weeks ago, he was interested in answering questions that folks may have about whether they are safe to use. Here are the results of our conversation.

Electric pressure cookers, like the Instant Pot, have grown in popularity in recent years. One reason for this is that they allow people to prepare meals more quickly. But a lot of people aren’t sure why electric and stovetop pressure cookers prepare food faster than conventional stovetop cooking. And many people also wonder whether pressure cookers are actually safe.

You have questions, we have answers.

Why does food cook more quickly under high pressure? (Or, why does food cook more quickly in an Instant Pot?)

Let’s talk about heat.

Hot air rises. So, when you cook in a regular pot on your stove, a lot of the heat escapes. When moisture in the food turns into steam (which happens at 212 degrees Fahrenheit if you’re at sea level), a lot of that moisture also escapes through evaporation.

But when you’re cooking in a pressure cooker, there’s nowhere for that hot air and steam to go – it’s trapped.

“Because the hot air and steam are trapped, a pressure cooker allows you to heat the moisture – steam and water – above its normal limit of 212 degrees Fahrenheit,” says Ben Chapman, a food safety researcher at NC State University. “And the pressure cooker traps that hot air and moisture with the food, which expedites the cooking process.

“In other words, the moisture surrounding the food itself reaches higher temperatures than it would without the pressure, which speeds up the chemical processes involved in cooking. But the food doesn’t dry out like it would in an oven or on a stovetop, because the moisture has nowhere to go.”

Are pressure cookers risky to use?

No, not usually.

Air and steam expand as they heat up. So, if no hot air and steam is allowed to escape, a pressure cooker can explode.

“Most modern pressure cookers have a safety valve that is designed to release hot air and steam when the pressure inside the vessel reaches a certain point,” Chapman says. “Once the pressure has been relieved, the valve shuts again.

“Modern pressure cookers should also have a release valve that allows you to vent hot air and steam before opening the lid. That’s important, because you don’t want the lid to fly off, or to get scalded by steam when you open the lid. (Even with the release valve, it’s a good idea to open the lid away from you.) In some models, the safety and release valves are located in the same part of the cooker.”

Can I cook frozen food in a pressure cooker? 

You can cook frozen food in anything. The real question is: “Is it safe to cook frozen food in a pressure cooker?” And the answer is yes.

“The food safety concern here is that you don’t want foods – like raw meat or poultry – to be in the temperature ‘danger zone’ for a long time,” says Natalie Seymour, a food safety extension associate at NC State. “That can happen if you’re cooking frozen foods in a crockpot or a slow cooker, or even in the oven.

“The danger zone is between 41 degrees and 135 degrees Fahrenheit (5-57.2 degrees Celsius), which is the temperature range that promotes pathogen growth,” Seymour says. “It’s also the temperature range that allows pathogens to produce toxins that can persist even after the temperature gets high enough to kill the pathogens themselves. Just killing the pathogens won’t make food safe if they have already created heat-stable toxins.”

In short, you can cook frozen food safely using anything, as long as you monitor the temperature to ensure that it spends less than four hours in that temperature “danger zone.” That can be challenging if you’re using a slow cooker.

“However, because of how they work, pressure cookers do a good job of getting foods through the temperature danger zone pretty quickly,” Chapman says. “That makes it safe to cook frozen foods in a pressure cooker.”

What’s the difference between a pressure cooker and a pressure canner? Can I use them interchangeably?

Pressure cookers and pressure canners are not the same thing, and you shouldn’t think of them as being interchangeable. A good rule of thumb is that you can use a pressure canner as a pressure cooker, but you cannot use a pressure cooker as a pressure canner.

“Pressure canners have to be able to reach and maintain a consistent internal temperature of 240 degrees Fahrenheit (115.5 degrees Celsius) in order to inactivate the spores that cause botulism poisoning,” Chapman says. “But pressure cookers are variable and often don’t reach temperatures of 240 degrees. Also, electric pressure cookers – like Instant Pots – run on a cycle, in which the internal temperature rises and falls. That means they can’t be used as pressure canners.”

Note: You can find additional resources for pressure canning here.

The only nut butter I really like is peanut butter

Foodborne pathogens seem to like lots of nut butters. This week’s pathogen in nut butter news comes to us from Thrive Market and surprise, it’s Listeria, not Salmonella.

According to Thrive Market, all unexpired lots of their nut butters after a supplier identified some Lm in the products. I guess the expired ones are okay? Expiration dates are really for quality anyway – and we don’t really have expiration dates, but whatever.

Thrive Market, Inc, is recalling all unexpired lots of the Thrive Market-branded nut butters listed below (“Product(s)”) due to the potential for contamination with Listeria monocytogenes. On January 21, 2019, one of our suppliers notified us that it was issuing a recall of all nut butters it has manufactured since January 2018 because of a positive test for Listeria monocytogenes in recent lots. Because the safety of our members is our absolute priority, we are expanding on our supplier’s recall and are voluntarily recalling all unexpired lots of all Thrive Market-branded nut butters manufactured by this supplier.

The public health impact of the contamination isn’t really clear to me – how much Lm? Are nut butters protective in the gut to Lm like they are to Salmonella? Not sure. That’s a  question for another day.

Why so many outbreaks in 2018? I’m not sure there were, but math is hard

Don and I recorded a podcast today and one of the potential show titles was math is hard.

I’m writing from experience, I had to take calculus in high school twice to get it. Explaining probability and risk is even tougher.

Some of the math of food safety illness burden comes down to this for me: There are billions of meals every year in the U.S. that don’t lead to foodborne illness.

That’s good.

There are millions of meals every year in the U.S. that do lead to foodborne illness.

That’s bad.

There was some buzz in the food and health media after a CNN article stated that CDC had investigated more multistate outbreaks in 2018, 21 in total, than any previous year.

That’s sorta true, but sorta not, depends on how it’s counted.

Rachel Rettner of Live Science talked to me about this last week and I shared the National Outbreak Reporting System (NORS) dashboard with her. This is a super cool tool that CDC has where they track all the reported outbreaks in the U.S. and the number isn’t 21. It’s probably closer to 4000. At least that’s around what has been reported into NORS annually since 2009 when reporting got better.

I’m throwing out the multistate part in my calculations, because the microbes don’t care about state lines or borders.

From the Live Science article:

Experts say that, although we heard a lot about foodborne disease in 2018, it doesn’t mean that we had any more outbreaks than usual. Indeed, it’s likely that the U.S. always has about the same number of outbreaks every year, said Benjamin Chapman, an associate professor and food safety specialist at North Carolina State University. But critically, health officials are getting better at detecting these outbreaks, Chapman said, leading to an increase in reported outbreaks in recent years.
“The science is getting better, and the public health resources are getting better, and we’re just getting better at finding things,” Chapman told Live Science

And although these outbreaks made headlines, there are hundreds more outbreaks that we don’t necessarily hear about that get investigated and reported every year. (An outbreak refers to an instance when two or more people get the same illness from the same contaminated food or ingredient, according to the CDC.)
Indeed, according to the CDC’s National Outbreak Reporting System, which summarizes data on U.S. reports of foodborne illness, there were about 4,000 foodborne illness outbreaks each year from 2012 to 2016, (the most recent years for which data is available). That’s up from only about 1,000 reported outbreaks in 2008.
That “looks like this big jump” in outbreaks, Chapman said. But the increase is really due to health officials getting better at “connecting the dots” to find more foodborne illness outbreaks, he said. In other words, the outbreaks were happening, but health officials just weren’t as good as detecting them.

Unfortunately, better detection of outbreaks means that the total number of reported outbreaks likely won’t be going down anytime soon.
“As we get better at reducing risk [of foodborne illness], we also get better at finding things we didn’t know were there,” Chapman said. “I don’t expect that we would have any less or any more outbreaks in 2019.”

Rewashing those pre-washed greens isn’t doing anything

If I’m eating pre-washed lettuce I just open the bag and throw it on the plate. Because there’s not much I can do, safety-wise, to it once it’s in my home. If there’s pathogenic E. coli, Listeria or Salmonella there (or others) I’m stuck with it.

Cindy Tran of the Daily Mail writes that Sydney, Australia nutritionist Susie Burrell recently talked about food safety risks on a local morning show including a recommendation to rewash prewashed leafy greens. 

She said people should always wash their store-bought salads, even if the packaging says ‘pre-washed’.

‘You must wash those ones out of the bags. It does say pre-washed but I would always wash it again because it has sat there for a long period, you don’t know what the turnover time is.’

I’m following recommendations from a bunch of my food safety friends who reviewed the literature on cut, bagged, washed, ready-to-eat leafy greens from a few years ago. In the abstract, they write:

The panel concluded that leafy green salad in sealed bags labeled “washed” or “ready-to-eat” that are produced in a facility inspected by a regulatory authority and operated under cGMPs, does not need additional washing at the time of use unless specifically directed on the label.

Leafy green food safety risks need to be addressed before they get to me, all I can do by washing it again is increase the chance I cross-contaminate the salad precursor in my home. My purchasing choice is based in trust that growers, packers and processors know what they are doing, and do it. But at best, they can only remove 90-99% of what is there with a wash.

And I can’t do any better.

365 burgers in a year, how many were cooked to 160F?

I like hamburgers, not enough to eat an average of one a day though. According to the Los Angeles Times, that’s what restaurant investor Lawrence Longo did in 2018. Added difficulty, he did it at 365 different restaurants.

When asked to describe the perfect burger Longo responded:

Not too much going on. Bun-cheese-meat-bun. If you have the right meat, the right bun, the right ratio, you don’t need any ingredients on that burger. The juices on that burger are all you really need.

I’d add that it was cooked to 160F and verified with a tip-sensitive digital thermometer.

 

Food safety and marketing folks should get together and improve messaging

One of the common discussions I have with industry folks is around the disconnect between marketing and food safety. The good food safety people will remain nameless, but a few times a year I hear at a meeting or via email/text/DM that someone in their organization doesn’t get food safety and puts stuff out without thinking of consequences.

John Bassett, friend of the blog (and pod) you can find him at @foodriskguy on Twitter, a great food safety risk assessment dude called out some folks at My Food Bag NZ (a Blue Apron-type meal service) for missing the mark on their messaging.

 

The good folks at My Food Bag responded with a canned response. I’d rather hear from their food safety folks.

 

 

Food Safety Talk 171: 350 Million Caesars

It’s a Christmas miracle as Don and Ben finally align schedules after snow kept Ben from his microphone and Don’s travel. After a little bit of banter on construction noises, and Canadian cocktails, the guys talk about egg nog and the effects of alcohol on Salmonella. The conversation goes to eating human flesh and brains (the guys are not fans) and mycotoxins in a fermented Chinese tea, puerh. Don and Ben chat about cleaning retail stores after recalled produce has been on display and whether Romaine lettuce is now worry-free.

Food Safety Talk episode 171 is now available here and at iTunes.

Show notes so you can follow along at home:

Everyone has a camera – even the restaurant operators

Doug and I have been talking about marketing food safety for years – the oft misunderstood concept. If you’re doing a good job at food safety tell everyone about it – differentiate yourself from your competitors. Complementing this idea is transparency and disclosure. Everyone has a camera.

In 2005 some keen public health folks in Korea started soliciting food safety-related pictures from diners as they ate and ordered at restaurants. The authorities wanted to enlist citizens to look for violations to place additional pressure on businesses to be decent food safety citizens – and to fine them for bad practices.

Five years ago we started a project, citizen food safety, on Instagram. Collectively capturing food safety, in the broadest terms through the lens of the camera phone-wielding public. This wasn’t just for the food safety nerds; its for the Interweb’s population of eaters: the regular folks who shop, eat at restaurants, visit farmers markets, cook or eat.

The hashtag #citizenfoodsafety still pops up sometimes on social media.

According to Xinhuanet, Health officials in the Chinese city of Hangzhou are actively calling on restaurant operators to be more transparent and put up cameras and offer patrons a live look on what’s going on in the kitchen. I love it. This advances #citizenfoodsafety.

Sure, folks can do weird stuff in blind spots, but this is a cool progression.

In an effort to alleviate food safety concerns that shroud China’s booming takeout services, the capital city of Zhejiang Province said over 150 restaurants had offered such services on a popular takeout app.

Hangzhou’s administration for market regulation said it was part of the city’s campaign to turn its eateries into “sunshine restaurants,” which install cameras or have open kitchens to allow for customer supervision.

The online live vetting aims to eliminate the “blind spot” as more restaurants jump on the mobile internet bandwagon to promote their takeout services, said Wang Jinchao, an official with the administration.

Consumers will feel relieved as they can see what happens in the kitchen, while the restaurants will be prompted to comply with the rules, according to Wang.

FDA’s update on Romaine-linked outbreak investigation – it is California stuff

The normal folks who I hang out with at the hockey arena have already started asking when they can start eating Romaine again (who knew there were so many Caesar fans).

FDA’s answer to when is soon

Some places never stopped serving it. 

Earlier today I told Korin Miller at Yahoo the below:

If you happen to visit a restaurant that tries to claim its romaine is safe, it’s really best to avoid the food. “I would send it back,” Benjamin Chapman, an assistant professor and food safety extension specialist at North Carolina State University, tells Yahoo Lifestyle. “When the CDC comes out with a message that says ‘Don’t eat romaine lettuce,’ you should heed that advice,” he says. “Right now, we don’t have any indication that it’s romaine from any certain part of the country or a certain company. It’s a standing blanket statement.”

And now we’ve got more information (that’s how quickly this stuff moves).

FDA announced late today that they have narrowed their investigation to field grown Romaine from Central Coast growing regions of northern and central California.

All other lettuce is as safe as it was last week before the announcement.

FDA is taking things a step further, in a really positive way in concept – asking producers to label where it came from.

Based on discussions with producers and distributors, romaine lettuce entering the market will now be labeled with a harvest location and a harvest date or labeled as being hydroponically- or greenhouse-grown. If it does not have this information, you should not eat or use it.

There is no recommendation for consumers or retailers to avoid using romaine lettuce that is certain to have been harvested from areas outside of the Central Coast growing regions of northern and central California. For example, romaine lettuce harvested from areas that include, but are not limited to the desert growing region near Yuma, the California desert growing region near Imperial County and Riverside County, the state of Florida, and Mexico, does not appear to be related to the current outbreak. Additionally, there is no evidence hydroponically- and greenhouse-grown romaine is related to the current outbreak.

During this new stage of the investigation, it is vital that consumers and retailers have an easy way to identify romaine lettuce by both harvest date and harvest location. Labeling with this information on each bag of romaine or signage in stores where labels are not an option would easily differentiate for consumers romaine from unaffected growing regions.