Food Safety Lecture–It is Still A Jungle Out There

Yesterday, I posted a blog that tried to summarize some of William Balistreri’s talk on Global Health.  He gave a 2nd Excellent Lecture on Food Safety at the Georgia AAP Nutrition Symposium.  One audience member suggested that this lecture was well-paired with the previous lecture as the awareness of food-borne illnesses might deter gluttony.

This lecture was packed with information regarding food safety; he highlighted the extensive and frequent food-borne illnesses.

Key points:

  • The problem of food-borne illness was put under a spotlight by Upton Sinclair in The Jungle (1906) which led to reforms in meat packing industry.  However, more work is needed
  • FSMA -Food Safety Modernization Act was signed into law in 2011; it’s aim is to create a proactive rather than reactive approach, Historic opportunity to increase food safety
  • Food-borne illnesses: 1 in 10 persons worldwide will be sick every year & leads to 1/2 million deaths worldwide each year.  125,000 deaths in children
  • Food-borne illnesses: 48 million cases in U.S. each year (CDC estimates) and 3000 deaths (MMWR 64:2, 2015)
  • Besides significant mortality rates for food-borne illnesses, they also contribute to post-infectious irritable bowel syndrome (~13% of all cases) and these illnesses can be indefinite
  • Social media, including “” and Yelp, will likely help identify outbreaks more quickly.  Newer molecular technologies during food processing has the potential to improve food safety.


  • For those who want to keep up food-borne illnesses, Dr. Balistreri recommended food safety news, which provides daily emails. Link to subscribe: Food Safety News
  • Two books that were recommended: The Poison Squad by Deborah Blum and Outbreak by Timothy Lytton
  • The CDC has plenty of advice and a useful pamphlet regarding the key 4 steps with food preparation: Clean, Separate, Cook, Chill.
  • Another resource:

Link to full talk slides PDF: FOOD SAFETY (10-10-19)  I have placed about 20 slides below which summarize much of the information that he conveyed.



Molecular Panels for Identifying Etiology with Acute GI Symptoms

A recent study (MR Nicholson et al. J Pediatr 2016; 176; 50-6) examined the use of multiplex molecular testing to determine the etiology of acute gastroenteritis in children.  It is interesting that little has been published about this increasingly common practice of sending a 12 to 15 panel PCR assay when faced with acute GI symptoms, mainly diarrhea.

This study was a prospective population-based study of children <6 years with acute gastroenteritis (2008-2011).


  • 70.4 % (152/216) samples tested positive for a pathogen, with norovirus the most frequent (n=78, 36.1%). Clostridium difficile was next at 16.2% (n=35).
  • 22.7% (n=49) tested positive for more than 1 pathogen including 25 with a C difficile detection
  • In this study, the authors noted C difficile colonization in 8% of healthy children aged 0-51 months and in 14% of children <12 months

Implications of this study and this technology:

  • Prior to this technology, traditional approaches typically identified less than 15% of the cases of acute gastroenteritis.  Thus, this new technology increases the likelihood of a definitive diagnosis.
  • Multiple pathogens, particularly with C difficile, illustrate how this new technology will present some difficulties with interpretation.  C difficile has very high rates of colonization in infants (anywhere from 25-80%) without AGE symptoms and lower rates of colonization in toddlers.  High colonization/detection has been noted in inflammatory bowel disease patients (17%) and pediatric oncology patients (30-55%).
  • For C difficile, molecular testing is much less likely to correlate with clinical disease than toxin-based assays. “A recent study in adults found that virtually all CDI-related complications occurred in patients with a positive toxin immunoassay.” (JAMA Intern Med 2015; 175: 1792-801)

My take: These panels are helpful in identifying infectious etiologies of AGE and may help prevent unnecessary endoscopic procedures.  Due to their limitations, careful selection of which patients to test and cautious interpretation of the results are needed.

Related blog posts:

Sunset from Bar Harbor, ME

Sunset from Bar Harbor, ME

What Will They Think of Next? A Vomit Machine for Studying Norovirus!

A summary of a recent report from NBC news:

Yuck! Vomit Machine Shows Why Norovirus Spreads So Fast

Here’s an excerpt:

They used another virus called MS2 that’s similar to norovirus, that doesn’t make people sick and that’s easy to grow in the lab.,,

“We think that there’s a at least a million particles released in a vomiting event and maybe more.”

Not all of it goes into the air. In fact, very little did in their experiments. But it was enough. They estimate that as many as 13,000 virus particles can be released into the air with a single retch. They made a video that shows how it works.

“There was evidence of aerosolized MS2 after every simulated vomiting episode,” they wrote in their report, published in the Public Library of Science journal PLoS ONE.

People can be infected with as few as 20 to 1,300 microscopic viral particles, so their study shows that vomiting could indeed spread the infection through the air….


“There are 21 million cases of human norovirus infection in the U.S. each year, and this virus genus is now recognized as the leading cause of outbreaks of acute gastroenteritis,” the researchers wrote.

It kills up to 800 people a year in the U.S. alone and puts 70,000 into the hospital, so understanding how it spread sand finding ways to stop it could prevent many illnesses, the researchers said.

Related blog posts:

Norovirus Impact on Young Children

As noted in a previous blog (Norovirus -now more important than rotavirus | gutsandgrowth), Norovirus has become the most important cause of gastroenteritis in children younger than 5 years.  More data to back up that claim has been published (NEJM 2013; 368: 1121-30).

The authors examined laboratory-confirmed cases of norovirus in children younger than 5 years with acute gastroenteritis in hospitals, emergency departments, and outpatient clinical settings during the years 2009 and 2010.  Using the New Vaccine Surveillance Network (NVSN), the authors undertook a 2-year prospective population-based survey with a catchment population of more than 141,000.  The specific sites included county populations around the University of Rochester, Vanderbilt University, and Cincinnati Children’s.


  • Norovirus was detected in 21% of children with acute gastroenteritis (2009-2010); it was also detected in 4% of healthy controls.
  • The age group with the highest rates of norovirus infection in this study were 6-18 months of age.
  • The GII.4 Minerva strain was most predominant strain in 2009 and GII.4 New Orleans in 2010. (In 2012, a novel GII.4 Sydney variant has emerged).
  • Rotavirus was identified in 12% of children with acute gastroenteritis (2009-2010).
  • Using this data, the authors extrapolated national estimates (for norovirus) of 14,000  hospitalizations per year (in this age group), 281,000 emergency room visits, and 627,000 outpatient visits.
  • The estimated costs exceed more than $273 million.

Related blog entry:

Closer to Star Trek Medicine

In Star Trek, Dr. Leonard McCoy used a medical tricorder to effortlessly diagnose a lot of conditions (Tricorder – Wikipedia, the free encyclopediaMedical tricorder – Wikipedia, the free encyclopedia).  While many of the newest diagnostic tests are not as portable, they share a feature of being able to diagnose a wide range of conditions quickly.  These tests include imaging studies like MRI and CT, genetic microarrays, and now PCR panels to diagnose a broad array of respiratory and gastrointestinal ailments.

One of the newest is the “xTAG GPP.”  With one stool sample, this Gastrointestinal Pathogen Panel (GPP) can detect at least 11 common bacteria, viral, and parasitic pathogens in about five hours.  Thus, all patients with identifiable gastroenteritis illnesses can be diagnosed more quickly.  The test relies on a “multiplex nucleic acid test.”

FDA News Release Jan 15, 2013  (Press Announcements > FDA permits marketing of first test that can ):

“Infectious gastroenteritis is an inflammation of the stomach and intestines caused by certain viruses, bacteria, or parasites. Common symptoms include vomiting and diarrhea, which can be more severe in infants, the elderly, and people with suppressed immune systems. Gastroenteritis can be spread easily through person-to-person contact and contaminated food, water, and surfaces. 
The Centers for Disease Control and Prevention reports that between 1999 and 2007 gastroenteritis-associated deaths in the United States increased from nearly 7,000 to more than 17,000 per year. Norovirus and Clostridium difficile accounted for two-thirds of the deaths. 
The xTAG Gastrointestinal Pathogen Panel (GPP), a multiplexed nucleic acid test, detects the following causes of gastroenteritis:
  • Campylobacter
  • Clostridium difficile (C. difficile) toxin A/B
  • Escherichia coli (E. coli) O157
  • Enterotoxigenic Escherichia coli (ETEC) LT/ST
  • Salmonella
  • Shigella
  • Shiga‐like Toxin producing E. coli (STEC) stx 1/stx 2
  • Norovirus
  • Rotavirus A
  • Cryptosporidium
  • Giardia
“Tests such as the XTag GPP that can detect viruses, bacteria, and parasites from one sample at the same time can help clinicians more quickly identify and treat what’s causing gastroenteritis,” said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostics and Radiology at the FDA’s Center for Devices and Radiological Health. “The test could also allow clinicians and public health professionals to more quickly identify and investigate the source of potential gastroenteritis outbreaks.”
The manufacturer demonstrated the performance of the xTAG GPP by collecting samples from 1,407 patients with suspected infectious gastroenteritis and comparing the xTAG GPP results to individual tests that are known to separately and reliably detect the 11 viruses, bacteria, or parasites associated with the xTAG GPP. The manufacturer also ran the test on 203 samples from patients with previously confirmed infectious gastroenteritis, and 313 additional specimens from pediatric patients with suspected infectious gastroenteritis. Results were comparable to the individual tests. Due to the risk of false positives, all positive results from the xTAG GPP need to be confirmed by additional testing (blog entry underlined for emphasis, not in original FDA release).
Luminex, Inc., of Austin, Texas, manufactures the xTAG.”
According to manufacter’s website, the test also detects Yersinia, Entamoeba histolytica, and adenovirus.  It reports sensitivity of of >94% for almost all pathogens (except Salmonella which was 84%) and specificity of >94% for all of the pathogens.