The Laboratorian - Volume 4, Issue 4


The Laboratorian - Volume 4, Issue 4
Laboratorian Header

April 2013 - Volume 4, Issue 4

Article Index

- Consumer Micro
- NBS 50th Anniversary
- TB Transmission


What is your mental picture when you think of a public health laboratory? Do you take an imaginary walk down our halls and see laboratorians in white coats injecting mysterious substances into test tubes or hunched over microscopes, humming scientific machines, anonymous figures in masks, their hands busy beneath biosafety cabinets...? But what are they doing? What you imagine is likely the result of your own experiences and knowledge – perhaps some of it gained through reading The Laboratorian.

We plan to dispel some of the mystery with a new feature. In each issue, we will tour a different area of the DSHS Laboratory. We will attempt to go beyond our beloved scientific statistics and tell you not only the kinds of testing done in each area but also a story to illustrate why each area is important to the health and wellbeing of Texans. Our first stop is Consumer Microbiology where we will learn about the testing done before food reaches grocery store shelves, how their analysis is instrumental in solving foodborne outbreaks, and what they do to make sure test results are accurate.

Help us celebrate the 50th anniversary of Newborn Screening and its impact on improving the lives of newborns. In May, Austin will host a travelling newborn screening display – one stop on a 13-state tour.

The next article is a fascinating riddle involving three cats and tuberculosis (TB). Did the cats give their owner TB or did the owner give them TB? See if you can find the answer to "The Question of Mutual Tuberculosis Transmission."

by Jimi Ripley-Black


Lab Tour: Consumer Microbiology

CMT members performing a fecal coliform test on baywater samples. Photo courtesy of Andrew Vinyard.

“Do you get free ice cream?” The question is common to nearly every group touring the Consumer Microbiology area. The kid in each of us lights up at a box of Blue Bell ice cream bars. The DSHS Laboratory Consumer Microbiology Team (CMT) also regularly tests Borden, Oak Farms and Amy’s Ice Cream. Milk and dairy products may be the most popular with tour groups, but food and water samples account for the largest testing volume.

“Is there anything you don’t eat?” Testing consumables actually doesn’t seem to faze laboratorians working in the area. “There aren’t too many things that we do not eat due to our jobs,” said Microbiologist Andréa Saldaña.

CMT member preparing a food sample for testing

In 2012, the team tested about 2,200 food and environmental samples (swabs taken from the food processing environment), which included samples from the DSHS Meat Safety Assurance Unit, DSHS Food Group, and DSHS Milk Group. The 2,200 samples tested for the DSHS Seafood and Aquatic Life Group included baywater and oysters screened for Brevetoxin. There were also 800 routine milk and dairy samples and 2,700 drinking water samples.


The CMT has been instrumental in solving food-borne outbreaks. In February 2009 a large-scale salmonella outbreak resulted in approximately 691 cases that spread across 46 States and Canada. Several analysts came in on the weekend, in shifts, to test the influx of samples. “I am proud to work with a group of people who work great as a team and who are willing to help each other out, even on the weekends, in order to get the needed results,” said Saldaña.

The suspected source of the salmonella was narrowed down to peanut butter. To test the peanut specimens, laboratorians blended them with a special Lactose enrichment broth. The resulting mixture was left to grow for 24 hours. The next day, the specimen was tested on the BAX® Q7 System, which is an automated and simplified version of traditional polymerase chain reaction (PCR). If the specimen showed a positive result, the specimen was plated and run with a spectrum of biochemical tests to more specifically identify the bacteria.

When 20 environmental swabs from the implicated processor went missing in transit, staff from the CMT and Check-in scoured the DSHS campus to make sure the package wasn’t here. The package was not found. The DSHS Foods Group staff were also looking for the package. The package was eventually found in a mail room at the Exchange Building around 9:00 PM. "I was called by the Foods Group Unit Manager and asked to process the samples," said CMT Team Lead Chris Malota. "If they weren’t processed that day, they would have had to been UNSAT. So I arrived to the lab and received the samples from the Foods Group at 10:15 PM that night. Samples were set up that night by me and we were able to save the samples. This illustrates the work put in by both the lab and the regulatory agency to find and test important samples in an outbreak situation."

Their hard work paid off. The CMT team isolated Salmonella typhimurium in peanut meal from a Texas peanut processor. To remove the source of the outbreak, the entire plant had to be shut down and the corporation's executives were indicted for fraud and conspiracy.

A hospital-acquired listeriosis outbreak began in February 2010; it would last for seven months and involve five hospitals. Investigators worked to identify the source through patient interviews, medical records reviews and hospital food source evaluations. The CMT was instrumental in the latter, testing multiple samples using culture and PCR. The last case patient was identified in August, but it wasn’t until October that the extensive investigation and testing efforts narrowed from chicken salad, the suspected source, to confirm a specific ingredient as the cause. Ten sample bags of diced celery were collected from the manufacturer; of these, seven were positive for Listeria monocytogenes. To learn more about the work of the CMT and the outbreak response, read "Hospital-Acquired Listeriosis Outbreak Caused by Contaminated Diced Celery—Texas, 2010," in the Oxford Journal of Clinical Infectious Diseases.

“In October 2010, while performing routine milk testing, we detected and isolated Campylobacter in one of our raw milk samples” said Microbiologist Isvara Sattviani. “The sanitarian was notified and the producer of raw milk could not sell their product until it showed no signs of Campylobacter. Multiple samples were collected and tested before the milk could be made available to the public.”

CMT analyst testing a raw for retail milk sample for Salmonella. Photo courtesy of Andrew Vinyard.

Though not many private individuals purchase raw milk, most do purchase milk or milk products. Interestingly, weather has a direct impact on milk and milk testing. Drought in recent years has impacted key areas of the United States cattle factory farming.

U.S. Drought Map

U.S. Factory Farm Map

As a result of drought and weather-related mold issues, corn has been strained as a source of feed. Texas started requiring that all raw cow milk be screened for Aflatoxin, the toxic byproduct of a mold that attacks corn during drought and can then be passed by cows to their milk. In 2010, the Milk Group notified all certified milk testing laboratories in Texas to test routine raw cow milk samples for Aflatoxin. This testing continues. All routine raw cow milk is tested for the presence of Aflatoxin. “Each month, we have an average of one positive sample for this laboratory,” said Malota. “We are not the only certified Texas lab. Though we only test a very small portion of the routine milk samples in Texas, this lab does perform all the pathogen testing on milk samples.” As a result of the strain in production, screening for other harmful substances, such as bovine growth hormone (BGH), has also been added.

Photo of a Coliform Plate Count on Petrifilm; this test enumerates coliform bacteria in dairy products. Photo courtesy of Andrew Vinyard.

All 10 CMT members are cross-trained in all areas of food and water testing. An analyst must be certified by the FDA Milk Program to test milk samples. First they must pass FDA Milk Splits, which is proficiency testing to become partially certified. Then they undergo an FDA inspection to become fully certified.

The CMT couldn’t do their work without the Consumer Microbiology-Quality Control Laboratory (CMT-QC). Three CMT-QC laboratorians test the quality and performance of all media made in-house by the Media Preparation Team, as well as any commercial microbiological media received for in-house uses. An average of 1,500 to 2,000 samples are tested each month for quality control.

The CMT-QC laboratory maintains a library of test organisms for quality control testing and for use by different teams in the DSHS Laboratory. Some of the reference organisms are also being lyophilized (freeze-dried) by the CMT-QC laboratory. “Lyophilization is beneficial in that it will decrease the cost incurred by having to order these organisms every four to five years,” said CMT-QC Microbiologist Natalie Perryman-Hale.

The CMT-QC laboratory team also processes and results approximately 61 spore tests every month for all autoclaves in the Laboratory, performs monthly checks of materials such as distilled water used for the preparation of media and reagents in the laboratory, and calibrates thermometers annually for 31 teams. The top priority of CMT-QC is to ensure accuracy by certifying that only the proper materials and media are used in testing.

CMT Food Methodologies for testing food, milk and dairy, shellfish and water are derived from the FDA Bacteriological Food Manual (BAM) and/or Association of Official Analytical Chemists (AOAC) Official Methods of Analyst.

The milk laboratory is a FDA certified laboratory for multiple tests. Surveillance testing is done on retail dairy products (milk, ice cream and other dairy samples, such as cream and buttermilk), raw milk, and raw for retail milk (bovine and caprine). Consumer Microbiologists also use standard plate and coliforms counting to estimate the count of the bacteria population in a sample. “There are several tests – such as Charm II, Charm SLBL, SL-3, and Charm SLFMQ – that we use to detect antibiotics in a sample. Charm SLFMQ (Aflatoxin) was added to our routine testing in July 2010,” said Sattviani. The latter test detects and quantitates aflatoxins in raw milk samples. One of the most carcinogenic substances known, aflatoxins (myotoxin) are produced by many species of Aspergillus, a type of fungus.

For shellfish, Consumer Microbiologists perform surveillance testing on Texas Baywater samples from oyster lease sites. “We test oysters for Brevetoxin using a live mouse bioassay in which we inject mice with the toxin that has been extracted, using ether, from the oysters,” said Saldaña.

Water samples come from both public water systems and private individuals. Consumer Microbiology is one of the only areas of the Laboratory that accepts samples from the public. A Colilert® rapid test is used to detect the presence or absence of coliforms and E. coli. If the water turns yellow, it indicates total coliforms are present and if it turns yellow and fluoresces under the ultraviolet light, it means that both coliform and E. coli are present.

Most questions from submitters pertain to water samples. All necessary information can be found on the Consumer Microbiology website. Submitter’s Frequently Asked Questions include the time frame for having potable drinking water tested – within 30 hours – and where to get sample bottles – from the DSHS Laboratory in Austin; they can be picked up or ordered from the DSHS Container Preparation Group by phone at 512-776-7661 or via email at Water testing currently costs $16.19.

by Jimi Ripley-Black 


Celebrating the 50th Anniversary of Newborn Screening

Fifty years ago, newborn screening in the United States began when Dr. Robert Guthrie developed a simplified test for phenylketonuria (PKU). The impact of that first, life-altering newborn screen test led to the launch of Newborn Screening Programs in each state across the nation. Since then, tests for many new disorders have been added to each state’s panel.

Newborn screening can make a tremendous difference in the health outcome for a child. Finding and treating these disorders early can prevent serious complications such as growth problems, developmental delays, deafness, blindness, intellectual disabilities, seizures and sudden or early death. Texas is proud to screen for 29 disorders via a newborn screening specimen, with the addition of Severe Combined Immunodeficiency (SCID) to the panel in December 2012. In addition, Texas newborns are screened in birthing facilities for hearing loss.

Photo of laboratorian working with Newborn Screening bloodspot cards

The Association of Public Health Laboratories (APHL) has chosen Texas as one of the states included on a 13-state tour of its traveling newborn screening display, which illustrates the history and highlights the immense impact of newborn screening.

The schedule of the APHL display’s visit to Austin:

Newborn Screening Laboratory, DSHS Central Campus

May 13 - May 14

Bernstein Building, DSHS Central Campus

May 15

Travis Building, DSHS Downtown

May 16 - May 18

State Capitol, Ground Floor Rotunda

May 19 - May 24

Lab employee reading a NBS 50th Anniversary poster


Whether you are a newborn screening healthcare provider, Newborn Screening Program staff, or someone who has been impacted by Newborn Screening, please join in the celebration!

If you live in the Austin area, please feel free to visit the APHL Newborn Screening Display at the Capitol.

For more information about Newborn Screening and its impact:

by Callie Bresette

The Question of Mutual Tuberculosis Transmission

In January 2013, the DSHS Laboratory was challenged to solve a riddle. Samples from three cats were submitted for Mycobacterium tuberculosis (TB) testing. The cats’ owner had recently passed away from Mycobacterium bovis, a TB complex. (TB complex is the common name for the group of bacteria generally considered responsible for all known contractions of the active tuberculosis disease.) Two of the cats tested positive and were reported to have respiratory disease. Did they transmit TB to their owner or did the owner transmit TB to them?

Laboratorian innoculating media

Transmission of disease from infected animals to humans is often in the news. These zoonotic diseases take the form of bacterial, viral, fungal and parasitic infections. They are transmitted through bites and scratches from an infected animal and through contact with secretions from the mouth, eyes and lungs. No one thought much about human to animal transmission or had any idea this was even possible until recently.

According to the Centers for Disease Control (CDC) TB factsheet, “In the United States, the majority of tuberculosis (TB) cases in people are caused by Mycobacterium tuberculosis (M. tuberculosis). Mycobacterium bovis (M. bovis) is another mycobacterium that can cause TB disease in people. M. bovis is most commonly found in cattle and other animals such as bison, elk, and deer. In people, M. bovis causes TB disease that can affect the lungs, lymph nodes, and other parts of the body. However, as with M. tuberculosis, not everyone infected with M. bovis becomes sick. People who are infected but not sick have what is called latent TB infection (LTBI). People who have LTBI do not feel sick, do not have any symptoms, and cannot spread TB to others. However, some people with LTBI go on to get TB disease.”

People are most commonly infected with M. bovis by eating and drinking contaminated, unpasteurized dairy products. This was consistent with the cat owner’s history. The pasteurizing process is what eliminates diseases

like M. bovis from dairy products. The CDC states that humans can be infected by direct contact with a wound that can occur during hunting, or by breathing in the bacteria in air exhaled by animals infected with M. bovis. Direct transmission from animals to humans through the air is thought to be rare; and it is still unclear if the cats gave their owner the disease first, or whether the reverse is the case, however, it is possible that the transmission occurred both ways. The samples were sent to the CDC for genotyping, and they confirmed the connection. TB and M. bovis can be spread directly from person to person through air droplets when the infected person coughs or sneeze, so it makes sense that this could also happen from pet to person.

Laboratorian reading florescent slides in the dark room

This raises a new question: do we let the cats die or do we treat their disease? If the latter, how exactly do we confirm that they are TB free? The complete answer to these questions is still unknown. Two of the cats are on antibiotic therapy. Only time would tell if the treatment is successful.

Next time you decide to kiss your pet, you might want to remember that even domestic animals carry diseases that can be transmitted to humans and that we can also pass along certain diseases, like TB, to our pets. And when the person next to you is coughing and sneezing, you might want to be a little skeptical when they say, “Just allergies.” Whether human to pet or human to human, a little space is a good precaution to prevent infection.

by Misi Adunbarin 


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April 2013, Volume Four, Issue Four                          (Publication #E14-13156)
Published by DSHS Laboratory Services Section
PO Box 149347, MC 1947
Austin, TX 78714

512 458 7318
888 963 7111, ext 7318 Toll Free
email The Laboratorian


Grace Kubin, PhD
512 458 7318
email Grace

Jimi Ripley-Black
512 458 7318, ext 6505
email Jimi

Last updated May 20, 2019