Rutgers hit with noro outbreak

Some Rutgers University students had a nasty gastrointestinal illness last week that is likely norovirus, according to the Daily Targum. Don and I talked about this outbreak on the podcast today. Rutgers has a few things working for them: the semester is over (leaving lots of time to clean and sanitize; and less places for the virus to be transmitted), and Schaffner is there providing some technical advice.

At least 35 students are complaining of feeling sick after a suspected virus broke out on campus around Dec. 7.10849902_719581291471357_3442145704847569295_n1-300x3001-300x300-1

Many of these students, who claim to have eaten in the Livingston and Brower Dining Halls, believe they are suffering from food poisoning. But University Sanitarian John Nason said he does not think this is a food-borne illness.

“The virus is people-to-people. We don’t believe it’s food-borne,” he said. “Most people are getting sick 90 minutes to two hours after eating, which doesn’t make sense. Most people who get sick after eating think it’s food poisoning.”

He said the onset time of 90 minutes to two hours does not equivocate to a food-borne virus, considering viruses such as E. coli and salmonella have an onset time of about six to 48 hours.

Managing a norovirus outbreak is a bit tricky, here are a couple of infosheets we’ve used/developed over the years that might be of use.

Norovirus is a problem for campuses and cafeterias

Vomiting and fecal episodes

A systematic look at the five-second rule: Miranda and Schaffner edition

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.giphy

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.”

The paper can be downloaded here, abstract below.


WORLD: Longer contact times increase cross-contamination of Enterobacter aerogenes from surfaces to food
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.


More on Modernist Cuisine and bad microbial food safety; Colbert, careful of Clostridium in the pastrami

Dr. Donald W. Schaffner, extension specialist in food science and professor at Rutgers University writes in this guest blog post:

A colleague emailed me a link the other day and asked for my opinion. He’s a raw milk advocate, so I was curious. The title was intriguing — The Complex Origins of Food Safety Rules, Yes, You Are Overcooking Your Food, a chapter precis from Modernist Cuisine — and one of the author’s names was familiar; famous in a famous Internet nerd sort of way. Sure enough Nathan Myhrvold is a famous nerd. And I do love me those Internet nerds. So, as I often do, I saved the link to read later. As I started reading several things impressed me, most notably, a rather clear description of D-values in an article written for the general public. Unfortunately, after that the article began to fall apart. I marked up a pdf copy on my iPad and emailed the comments off to my colleague.

The next day, I was still thinking about the article. I emailed Doug to let him know I was interested in blogging about it. He was encouraging, and shared with me what he’d written already, which included a clip of Myrvold’s appearance on the always entertaining Colbert Report. Essentially, I agreed with Doug, so if you are one of those TL;DR blog readers, you can stop now and get back to work.

The book chapter has a light and breezy style, and who doesn’t love that, but in their attempt to be conversational, the authors miss the mark.

"Right away, you can see that decisions about pathogen-reduction levels are inherently arbitrary because they require guessing the initial level of contamination."

Arbitrary is defined as, "Based on random choice or personal whim, rather than any reason or system" and while I’ll be the first to note that food safety standards often lack consistency, they are not random. The problem is historical standards were developed at a time when understanding of risk, including microbial risk, was rudimentary. Quantitative microbial risk assessment applied to food has only been around for 10-15 years, while food safety laws have evolved over centuries. As a former CTO (nerd speak for chief technology officer) for a company that had to deal with backward compatibility of Microsoft operating systems (operating systems that I not longer use – sorry, I’m that guy), you’d think Myhrvold might have a better appreciation of that fact. Further, it’s not a matter of "guessing" the initial contamination level, it’s a matter of understanding that the initial contamination level in foods is variable, and for any food in question, is unknowable without testing that food for the presence of pathogens. As a physicist, Myhrvold should understand that we can’t observe a system (test for pathogens) without disturbing its state (have nothing left to cook).

Myhrvold and his cookery co-authors do make good points that show a level of understanding sometimes lacking in food safety professionals that were asleep during the lecture on D-values. They are completely correct that, "No matter what the standard is, if the food is highly contaminated, it might still be unsafe" after cooking. Because bacterial survival during cooking is a probability game, if a food is contaminated at the low level, it might contain pathogens after "proper" cooking just by bad luck alone.

Myhrvold et al. state "To compensate for this inherent uncertainty, food safety officials often base their policies on the so-called worst-case scenario," yet inherently contradict themselves by stating, "There are no guarantees and no absolutes.” Instead, food safety policy makers base their recommendations on conservative assumptions. Exactly how conservative to make those assumptions, and what other factors come in to play, is a risk management discussion, and not a discussion solely based on science.

One of the problems with Myhrvold and his co-authors is while they might understand the mathematics of microbial destruction, as well as the culinary arts, their understanding of food microbiology is sorely lacking. They talk about, "required pathogen reductions … range from a 4D drop for some extended-shelf-life refrigerated foods… to a 12D drop for canned food, which must last for years on the shelf" and they imply from this, that somehow these regulations are flawed. As any food microbiologist knows (even the ones that slept through the lecture on D-values), the risks posed by extended-shelf-life refrigerated foods are quite different that the risks posed by canned food. The target pathogen in extended-shelf-life refrigerated foods is likely Listeria monocytogenes or perhaps nonproteolytic Clostridium botulinum, while the target for canned foods is proteolytic Clostridium botulinum for safety and Clostridium sporogenes for spoilage.

Myhrvold and friends have a complete lack of citations and references. For a book about the art and science of cooking, some degree of citation back to the literature or the relevant regulations would be appreciated. Some of the best writing being done today, whether long form or short recognizes the need to cite primary sources. This is hardly new, as one of my favorite science writers of all time (SJG RIP) pointed out more than 20 years ago.

For example Myhrvold et al. talk about something called "General FDA cooking recommendations" and note that "fresh food are set to reach a reduction level of 6.5D," and from the context I’m going to google-guess they mean the FDA model food code recommendations for cooking to eliminate Salmonella. In that same paragraph, Myhrvold et al. state that "Many nongovernmental food safety experts believe this level is too conservative." While this might be true, I have no way to check this supposed fact.

Myhrvold et al. go on to talk about "An expert advisory panel… 2003 report [that] questioned the FSIS Salmonella reduction standards for ready-to-eat poultry and beef products." I’m pretty sure they mean the 2003 book entitled Scientific Criteria to Ensure Safe Food. I was part of that National Academy of Sciences committee that authored the book, and yes, we did call out the U.S. Department of Agriculture’s Food Safety Inspection Service for "an excessively conservative performance standard.” We did this on page 9 (executive summary), in the body of the book on page 161 and on page 262 on our summary. The particular quote that I’d like to mention from the book however appears on page 148. Here we say, "Regulatory agencies need to properly set performance standards. This is a balancing act between setting a highly conservative performance standard and setting an excessively tolerant one." So, yes, while we did call out FSIS in that particular instance, we also recognize that there is a balance to be struck.

Myhrvold et al. make the statement that "in food safety, cross-contamination is often the weakest link." While it’s true that cross-contamination is being increasingly realized as a means by which foodborne pathogens can cause disease, a research effort to which we have contributed, I’m curious how Myhrvold et al. determine that it is often the weakest link. They go on to state, "One powerful criticism of food safety standards is that they protect against unlikely worst-case scenarios yet do not address the more likely event of cross-contamination." While it’s true that a cooking standard does not offer any protection against cross-contamination, other standards may reduce cross-contamination risk. For example, that 2003 book, Scientific Criteria to Ensure Safe Food, does note that "the Norwegian Agriculture Department is testing broiler flocks for Campylobacter and requiring positive flocks to be slaughtered after negative flocks to avoid cross-contamination at the plant; carcasses from positive flocks are then cooked or frozen under supervision," page 49, in case you’d like to check my facts. Check page 51, same book, and you’ll learn than "In Denmark… pork herds that have a high prevalence of Salmonella… are slaughtered separately from animals that come from herds with a low prevalence of Salmonella in order to avoid cross-contamination during slaughter and dressing; they are also used only in cooked products."

Myhrvold et al. call out "Another conservative tactic used by health officials" which is "to artificially raise the low end of a recommended temperature range." Myhrvold himself demonstrates this fact in his appearance on the Colbert Report where he feeds Stephen pastrami cooked for 72 hours at 130 F. However, I disagree with the implication that this is somehow a vast conspiracy designed to insure people eat overcooked foods. A quick check of the USDA FSIS Appendix A guidelines shows that USDA does indicate that meat processors can cook meat at 130 F and that a 7D cook for Salmonella is reached in 121 minutes. Myhrvold et al. go on to state that “Most food pathogens can be killed at temperatures above 50 degrees C / 120 degrees F, yet food safety rules tend to require temperatures much higher than that.” The authors further state, “Technically, destruction of Salmonella can take place at temperatures as low as 48 degrees C / 120 degrees F given enough time” and “There is no scientific reason to prefer any one point on the reduction curve.”

This is where the authors’ complete lack of food microbiology experience shines through. They provide no proof of their assertion that most pathogens are killed above 120 F, but here’s the rub: some pathogens, including those like C. perfringens that might have been present in Colbert’s pastrami actually start to multiply at temperatures between 120 and 130 F, so in fact there is a very good reason to use cooking temperatures above 130 F. Hopefully Myhrvold used a calibrated thermometer, we don’t want to see Stephen on the celebrity food poisoning list.

Myhrvold et al. rail about "unscientific food safety standards." Any such standard is a policy or risk management decision. While it’s good to have science or risk-based standards, there is no such thing as a “scientific standard” because any standard, guideline or criteria must consider far more than the science.

Myhrvold et al. further rant against  “public health authorities” in what I assume was the 2006 E. coli O157:H7 outbreak in fresh spinach claiming that they “told consumers, retailers, and restaurants to throw out all spinach, often directly stating in public announcements that it could not be made safe by cooking it.” According to my search I don’t see any Food and Drug Administration statement about cooking at all. FDA did “advise consumers to not eat fresh spinach or fresh spinach-containing products until further notice.” A search of the U.S. Centers of Disease Control found this advice for consumers: “E. coli O157:H7 in spinach can be killed by cooking at 160 Fahrenheit for 15 seconds.”

Myhrvold et al. note "The authorities must have decided that the benefits of avoiding multiple accidental deaths far outweighed the costs of simply tossing out all spinach," and I think they are probably correct. If you’d like to read a thoroughly researched discussion of the outbreak (with actual references!) focusing on what did consumers know, where did they get that information, and what did they do in response to the advisories issued by the FDA warning them not to eat fresh spinach, this article from my colleagues at Rutgers University would be a good place to start.

Rather than focus on whether or not advice was provided about cooking, if one were to criticize “public health authorities,” a better place to start might be whether any recall at all was needed. A review of the epidemic curve shows that by the time of the first FDA announcement on September 14, 2006, the outbreak was essentially over. In defense of my hard working colleagues in public health, as I once heard Paul Mead say, “Food safety recalls are always either too early or too late. If you’re right, it’s always too late. If you’re wrong, it’s always too early.” At least I think I heard him say that. The only source for that quote that I could find on the Internet is me.

Myhrvold et al. then move from a discussion about E. coli in spinach to Trichinella in pork, calling the recommendations (which ones? citation please) “ridiculously excessive." While it does appear from the literature that incidence in pigs is declining over time and is generally low, that unlike bacterial pathogens, Trichinella larvae are found in the muscle, not just on the surface. In any event, it appears that a microbial risk assessment is possible and if Myhrvold et al. have completed one, please do submit it for publication, and request me as an editor.

Myhrvold et al. call out, "Cooking standards for chicken, fish, and eggs, as well as rules about raw milk cheeses, all provide examples of inconsistent, excessive, or illogical standards.” Inconsistentcy is to be expected, given that different people developed different standards at different times and for different reasons. Is this a good thing? Probably not. Is it starting to change? I’d say that I’m cautiously optimistic, and kudos to those who are trying to move forward and use risk-based or risk-informed decision making processes.

While it’s true that, “A chef’s livelihood may depend on producing the best taste and texture for customers,” it’s also true that a chef’s livlihood livelihood requires customers that remain alive.

Myhrvold et al. state, “so if that meat were inherently dangerous, we’d certainly know by now.” Barbara Kowalcyk has some idea on the inherent risks from meat, the difference is that she’s actually doing something about it. Myhrvold et al. go on to state, “Scientific investigation has confirmed the practice [eating raw steak] is reasonably safe — almost invariably, muscle interiors are sterile and pathogen free. That’s true for any meat, actually, but only beef is singled out by the FDA." Except some steaks are subject to blade tenderization, a practice that can internalize any pathogens on the surface, so just because it’s an apparently intact piece, doesn’t meant that it’s pathogen free. And FDA doesn’t regulate beef, USDA FSIS has that responsibility. Assuming that Myhrvold et al. didn’t get the name of the agency wrong, then they must be talking about the FDA model food code, which is in fact not a regulation at all but model that “assists food control jurisdictions at all levels of government by providing them with a scientifically sound technical and legal basis for regulating the retail and food service segment of the industry.” And if Myhrvold et al. don’t like what the FDA model code says, they can change it (see below).

Myhrvold et al. note “Traditional cheese-making techniques, used correctly and with proper quality controls, eliminate pathogens without the need for milk pasteurization.” As they themselves have remarked earlier in the chapter, “There are no guarantees and no absolutes.” So it’s not that the French “eliminate pathogens” its just that they reduce pathogens to levels that the French consumer finds acceptable. Myhrvold et al. actually go on to make my point for me when they say "Millions of people safely consume raw milk cheese in France, and any call to ban such a fundamental part of French culture would meet with enormous resistance there." This is exactly why it doesn’t come down to science in the end. Science informs, but policy makers then deliberate, considering the science and other factors (including cultural preference), before making a decision.

Myhrvold et al. go on to note a variety of issues around raw milk cheeses including standard for import into the U.S., crossing state lines and sale within individual states and the province of Quebec, ending with, "How can these discrepancies among and even within countries persist?" It comes down to politics. And they are right; it is politics, or at least it’s food safety policy. The situation persists in the U.S. because FDA governs interstate commerce, while in-state commerce is the province of the state (or the province) and good policy considers the science, evaluates the risk and then makes a decision that is viable within that geographical boundary. They are absolutely spot on when they say “changing a regulation is always harder than keeping it intact, particularly if the change means sanctioning a new and strange food or liberalizing an old standard.” But change is possible, especially when it’s based on science.

Not content with making misstatements about food microbiology, Myhrvold et al. venture in to epidemiology, noting that many people apparently incorrectly believe “that chicken is the predominant source of Salmonella” and that "In a 2009 analysis by the CDC, Salmonella was instead most closely associated with fruits and nuts, due in part to an outbreak linked to peanut butter in 2006." Foodborne disease attribution is actually kind of complicated and while many Salmonella cases in the U.S. in 2006 might have been due to fruits and nuts, that doesn’t mean that this is always the cases year over year, or that somehow chicken is risk free.

Myhrvold et al. bring things to a close by providing the closest thing to a real citation by mentioning a National Advisory Committee on Microbiological Criteria for Foods (NACMCF) publication in the Journal of Food Protection in 2007 where they discover some “amazing admissions” from this panel of “health officials” that at least to my untrained eye looks to be mostly food microbiologists and one biostatistician. I was a member of that committee.

In the U.S. there are no “consumer regulations” that govern how people are to prepare foods in their own homes. If there were such regulations, they wouldn’t be administered by FSIS. Assuming this is a typo and they meant to write “recommendations,” these recommendations are in fact written by USDA FSIS Food Safety Education Staff whose mission is to inform consumers about the importance of safe food handling. The charge to NACMCF was in response to a real problem, as noted in the JFP article. “The questions were generated in response to foodborne illnesses from Salmonella related to the consumption of processed chicken products that appeared to be ready to eat (RTE) but contained poultry that was not ready to eat (NRTE).” And the FSIS staffers listened to our recommendations, reducing the whole muscle instantaneous cooking temperature from 180 F to 165 F, quite an impressive feat to “liberalize an old standard.” And while I’m delighted to learn that apparently “chicken cooked at 58 degrees C /136 degrees F and held there for the recommended time is neither rubbery nor pink,” I’d feel more confident if Myhrvold et al. provided a citation.

I’m all for letting “chefs and consumers be the ones to decide what they would prefer to eat.” I’m a food libertarian. You can eat what you want, whether you are a consumer or a chef, but if you are a chef, and you are cooking for me, I’d prefer that you calibrate your thermometer and that you follow a validated cooking protocol.

It seems that much of what Myhrvold et al. object to are the recommendations in the FDA Model Food Code. The Food Code is developed in a transparent and public process. Details can be found on the Conference for Food Protection Web site. Nathan Myhrvold, are you busy April 13 – 18, 2012? We are always chronically short of consumer representation on each of the three councils. Do you want to add to your already impressive resume? If you come to Indianapolis, Indiana, I’ll buy the beer.

Dr. Donald W. Schaffner is Extension Specialist in Food Science and Professor at Rutgers University. His research interests include quantitative microbial risk assessment and predictive food microbiology. In his free time, he reads blogs on the Internet.

Research shows how easily bacteria can thrive and spread within family kitchens

Colgate Palmolive and Don Schaffner (right, pretty much as shown) have hooked up to help spread awareness about safe kitchen practices.

Schaffner did a lit review, and I like that the press release has references – so many don’t; I don’t like that it repeatedly says food safety is simple and easy – it isn’t.

Research shows that E. coli, Salmonella and Staph can thrive on dishes and other kitchen surfaces.1 Whether putting away groceries or rinsing fresh vegetables, even the most careful cook can pass bacteria to new kitchen surfaces through the simple process of preparing a dish.

To help spread awareness about safe kitchen practices, the Palmolive® brand partnered with Donald W. Schaffner, Ph.D., renowned microbiologist and professor at Rutgers University. As an author of nearly 100 food microbiology studies, Dr. Schaffner was among the first to quantify how bacteria transfer during common kitchen tasks.

To demonstrate how easily cross-contamination can occur, Dr. Schaffner conducted a comprehensive review of his bacterial studies and those of leading universities and institutions worldwide that specialize in food safety research. Key research findings from this analysis include:

Bacterial Build-Up on Cutting Boards: Bacteria on a cutting board can double after 10 minutes of use, whether cutting raw meat or vegetables.2
Cutting Board Cross-Contamination: Ten percent of bacteria on a cutting board can transfer to lettuce while chopping.3
Survival of E. coli on Dishes: E. coli that remains on washed and dried dishes can survive up to three days.4

"Studies consistently demonstrate how easily bacteria spread throughout a kitchen – both bacteria-contaminated foods and hands can pass bacteria to dishes, cooking utensils and other ingredients," said Dr. Schaffner. "Yet, according to the research, even when cooks understand the ways bacteria can spread, they often fail to follow the simple precautions that can help reduce the risk of bacterial cross-contamination in the kitchen."

Consumers generally understand the causes of cross-contamination, such as not washing or changing the cutting board and other utensils between the preparation of meat and ready-to-eat foods.5 Despite this knowledge, many do not practice these safety measures while preparing meals. A recent study revealed that two-thirds of consumers failed to adequately wash hands after handling raw chicken, nearly 30 percent failed to wash or change the cutting board after cutting raw chicken and one-third failed to wash or change a knife used to cut raw chicken before cutting raw vegetables.6

"We know that consumers want to do everything they can to keep their kitchens clean and their families safe," said Dave Wilcox, Vice President, Product Safety, Regulatory & Quality, Colgate-Palmolive. "Using Ultra Palmolive® Antibacterial Dish Liquid to clean knife blades, dishes and other hard, nonporous kitchen surfaces throughout your cooking prep and clean-up process is a simple step that can help put your cooks’ minds at ease."


1"The importance of hygiene in the domestic kitchen: Implications for preparation and storage of food and infant formula." 2009. Perspectives in Public Health, March. Vol. 129 No. 2 l.

?2 "Use of Microbial Modeling and Monte Carlo Simulation to Determine Microbial Performance Criteria on Plastic Cutting Boards in Use in Foodservice Kitchens." 2004. Food Protection Trends, Vol. 24, No. 1: 14-19.

3 "Quantification and Variability analysis of Bacterial Cross-Contamination Rates in Common Food Service Tasks." 2001. Journal of Food Protection, Vol. 64, No. 1: 72-80.

4 "The survival of foodborne pathogens during domestic washing-up and subsequesnt transfer onto washing-up sponges, kitchen surfaces and food." 2002. International Journal of Food Microbiology, Vol. 85 (2003): 213- 226.

5 "Bacterial Contamination of Hands Increases Risk of Cross-contamination among Low-income Puerto Rican Meal Preparers." 2009. Journal of Nutritional Educational Behavior, Vol. 41:389-397?

6"Cooking Practices in the Kitchen-Observed Versus Predicted Behavior." 2009. Risk Analysis, Vol. 29, No. 4. DOI: 10.1111/j.1539-6924.2008.01189.x

Facing a recall without superhero senses leaves some vulnerable to confusion

I don’t like fresh tomatoes. Generally, my careful avoidance of them is a fairly unique practice. At least, I thought so until I met Bret. We stand together in our quest for vegetables that don’t leak acid on the rest of the salad.

We were on our honeymoon when the outbreak of Salmonella Saintpaul in tomatoes and/or hot peppers hit the news. Many people joined our stance on tomatoes then… but it took me a while to realize it.

Since I wasn’t reading FSnet while we were gone, I had to hear the warnings put out on eating tomatoes like a regular consumer would. It was like my superhero senses were turned off.

At the time, I wasn’t in the habit of watching the news. And according to the results of a Rutgers Food Policy Institute (FPI) survey,

“The majority of respondents (66 percent) first heard about the advisory on television.”

Throughout our trip, we ate at cafes, buffets, and casual dining establishments. When we didn’t eat out, we stopped at Wal-Mart for cereal and sandwich supplies. None of those places showed signs of produce being recalled.

The survey found,

“A small minority (8 percent) first heard about it from restaurants and retailers.”

As it happened, some of the first news I received came from my step-dad’s mom, who understood the problem to be in tomatoes sold with the vine still attached.

Hearing through the tomato-vine was problematic, though. I later learned the CDC advised,

“…persons with increased risk of severe infections…should not eat raw Roma or red round tomatoes other than those sold attached to the vine or grown at home…”

Those two words, “other than”, were missed (or misunderstood) at some point in the chain of communication that ended with me.

Lead author of the Rutgers FPI report, Dr. Cara Cuite said in a press release,

“Our results suggest that consumers may have a hard time taking in many details about these types of food-borne problems.”

Almost half (48 percent) of people surveyed indicated they were not sure which types of tomatoes were under suspicion.

I was back at superhero headquarters (i.e. in front of my Mac) when Salmonella Saintpaul was found in a sample of jalapenos from Mexico, and again when the outbreak strain was isolated from a Mexican serrano pepper and the water used to irrigate it.

Most consumers weren’t so lucky. From the survey,

“The researchers found that while almost all respondents (93 percent) were aware that tomatoes were believed to [be] the source of the illness, only 68 percent were aware…that peppers were also associated with the outbreak.”

Dr. Cara Cuite commented in the press release,

“This research is especially timely in light of the growing number of recalls as a result of the Salmonella outbreak associated with peanut butter and peanut paste.”

How can consumers be better informed? One practice seen in both outbreaks that helped alleviate some confusion was the use of club membership or “loyalty card” information to contact customers who had recently bought recalled products.

What else can be done to clear things up? After all, regular consumers don’t have superhero senses.

Don Schaffner, guest barfblogger: Raw milk seminar series update

As many of you reading this blog may know, Rutgers University has sponsored a seminar series on the topic of raw milk.  I am scheduled to present the fourth and final talk in the series on Monday.  Today (April 3, 2008) I attended the third talk in the series: “Raw Milk, A Microbiology Primer” presented by Dr. Mark Gebhart, an MD with Wright State University.

Dr. Gebhart is a licensed physician and board certified medical specialist practicing in Ohio.  Dr. Gebhart has worked in acute care medicine as a clinician, teacher, and researcher.  Dr. Gebhart has taken special interest in raw milk obtained from grass fed cows and believes many of the gastrointestinal disorders affecting millions of Americans could be cured by consumption of this product.  

Gebhart spent the first half of his time pointing out in great detail that raw milk contains multiple redundant systems of bioactive components that reduce or eliminate pathogens.  He proceeded to show a series of slides listing more than twenty of these components (e.g. lactoperoxidase, medium chain fatty acids, B-lymphocytes, lysozyme, etc.).

Gebhart’s focus then shifted to the microbial risks in raw milk.  He cited one study from a reputable journal (Applied and Environmental Microbiology) that showed that levels of the pathogens Campylobacter decline over time in raw milk.  When questioned by one audience member – Dr. Tom Montville – about CDC (Centers for Disease Control and Prevention) statistics showing many foodborne disease cases linked to raw milk, Gebhart said the he believed the epidemiological links to raw milk were not conclusively proven.

Gebhart then shared some statistics from two different sources (American Journal of Public Health and the CDC) that show that there were only 1.9 cases of raw milk food poisoning per 100,000 people, vs. 4.7 cases of pasteurized milk food poisoning per people 100,000.  Gebhart thought that these data made a compelling point in favor of raw milk, until another audience member – Dr. Mukund Karwe – pointed out that many more people consume pasteurized milk than raw milk.  Gebhart then stated that he needed to double check his references.

Gebhart then shared a number of slides in quick succession on a variety of topics including information on the effect of pasteurization on human breast milk, the safety of milk from cows with access to pasture, and the ability of some pathogens (spore formers like B. cereus and C. botulinum) to survive pasteurization.  Gebhart quickly wrapped up his talk as the debate between different audience members began to drown him out.

I can’t wait to see how things go on Monday.

Don Schaffner is an Extension Specialist in Food Science at Rutgers