Thursday, February 27, 2014

FDA Addresses Pet Food Safety; Universities Test Raw Pet Food for Salmonella Using PCR

For the first time, the Food and Drug Administration is taking steps to make animal feed and pet food sold in the United States safer.

A new proposed rule issued Friday aims to protect all animal foods from disease-causing bacteria, chemicals and other contaminants.

Under the rule, manufacturers will be required to develop procedures to prevent foodborne illness. For the first time, manufacturing facilities would have to follow proposed good manufacturing practices to address issues like sanitation. They will also have to have plans in place to correct any problems.

"Unlike safeguards already in place to protect human foods, there are currently no regulations governing the safe production of most animal foods," said Daniel McChesney, director of the Office of Surveillance and Compliance at FDA's Center for Veterinary Medicine, in a statement. "There is no type of hazard analysis. This rule would change all that."

The agency said its goal is preventing any transmission of contaminants that could cause animals and people to become sick.

If an animal eats contaminated food, McChesney noted, people can become sick if an animal enters the food supply. In addition, pet food contaminated with bacteria such as Salmonella can sicken people if pet owners handle the food, for example, or place it on a counter.

"The FDA continues to take steps to meet the challenge of ensuring a safe food supply," said FDA Commissioner Dr. Margaret Hamburg in a statement. "Today's announcement addresses a critical part of the food system, and we will continue to work with our national and international industry, consumer and government partners as we work to prevent foodborne illness."

The new rule complements proposed rules published in January aimed at produce safety and facilities that manufacture food for humans, said Michael Taylor, deputy commissioner for Foods and Veterinary Medicine.

Universities to Test Raw Pet Food for Salmonella

In a related story, University microbiologists will test raw pet food for Salmonella using PCR.

A Center for Veterinary Medicine study showed that 7.6 percent of the raw pet food tested contained salmonella, according to the Food and Drug Administration. But identifying the source of contamination--be it in raw materials or the manufacturing process--is difficult, according to South Dakota State University Senior Microbiologist Seema Das.

Through a five-year FDA grant for nearly $500,000, she will determine whether a test that detects salmonella in human food can do the same in raw pet food. The first year the test will be validated, and then either adjustments or expansion of the testing will be done in subsequent years. The work will involve multi-lab validation with collaborators at Iowa State, Texas A & M, the University of Minnesota and the New Jersey Department of Agriculture.

Protecting Humans

“This is not only a pet health issue, it is a human health issue because everything is interlinked,” Das said.

When a pet owner handles the raw food, he must wash his hands carefully and thoroughly disinfect any surfaces the food touched, Das explained. If not, contamination may occur.

“If the pet food is contaminated with salmonella, it goes from the pet food to you,” she noted. That’s why the FDA has made this a priority.

The high number of product recalls over the last 10 years is cause for concern, according to national food safety manager Brenda Stahl of testing laboratory, EMS Analytical, Inc. In an article in Food Safety News, she points to manufacturing, rather than to raw ingredients, as being the culprit 90 percent of the time.

Detecting Salmonella

After reviewing the recalls, Das and her research team suspect that mice or other rodents may be possible sources of contamination. Rodents and bugs can be problematic in factories where food is produced, Das explained. Salmonella is a common pathogen in mice.

The SDSU team, consisting of veterinarian Russ Daly, bacteriologist Laura Ruesch, microbiologists Marciel Aguiar and Cindy Watt and two undergraduate students, began working on the project in September.

The team has determined the lowest level of salmonella that the polymerase chain reaction, or PCR, system can detect in a sample. To do this, they took pathogen-free mouse droppings and spiked them with varying levels of salmonella, Das explained.

“We inoculate the mouse feces and then run the test,” she said. The PCR method can detect salmonella at dilutions as low as 15 colony-forming units per milliliter.

At each stage, PCR results are compared to those obtained through conventional bacterial culturing. The PCR test produces results within two to three days, while culturing takes four to five days.

The team will next examine specimens spiked with various amounts of salmonella including some that are just above the lowest detectable level and other samples with no salmonella. Das explained that 100 percent of the samples with salmonella at higher levels should test positive and all those without should be negative.

“This is the FDA requirement for validating a microbiological method,” she added. After the test has been validated in-house, Das will send trial samples to the other diagnostic labs.

Validating Procedure

During the final stage of validation, the collaborating labs will not know which samples are positive or negative. Once the PCR method has been completed and verified with mouse feces, the researchers will move on to raw pet food as a test platform.

The FDA Level 3 validation involves five labs, Das explained; therefore, “you know the method works.”

Through this research project, the FDA will have a proven method to identify the source of the contamination when a recall occurs.

From a production standpoint, the testing procedure will minimize the economic impact on the company. In addition, the FDA will have a valuable tool with which scientists can deal with a threat to human health while also protecting the pet food supply.

About the Animal Disease Research and Diagnostic Lab

Since 1887, the South Dakota State University Animal Disease Research & Diagnostic Laboratory has served the public by providing high quality veterinary diagnostic services as a means to promptly and accurately establish causes of animal health problems. Such diagnoses aid attending veterinarians and health officials in the treatment, control, prevention and surveillance of animal diseases, benefiting South Dakota and national livestock industries, other animal owners and public health. Research work involves basic and applied investigations that enhance the understanding of the induction of diseases in animals, the development of diagnostic methods for the detection of diseased animals, products for treatment or prevention of disease and management protocols for the control of disease.

Wednesday, February 5, 2014

Rice University Develops Rapid Microcantilever Biosensor for Detecting Salmonella in Food

An array of tiny diving boards can perform the Olympian feat of identifying many strains of salmonella at once.

The novel biosensor developed by scientists at Rice University in collaboration with colleagues in Thailand and Ireland may make the detection of pathogens much faster and easier for food-manufacturing plants.

A study on the discovery appears online this month in the American Chemical Society journal Analytical Chemistry.

The process appears to easily outperform tests that are now standard in the food industry. The standard tests are slow because it can take days to culture colonies of salmonella bacteria as proof, or laborious because of the need to prepare samples for DNA-based testing.

The Rice process delivers results within minutes from a platform that can be cleaned and reused. The technology can be easily customized to detect any type of bacteria and to detect different strains of the same bacterium, according to the researchers.  In the following picture, the small device seen under the magnifying glass is an array of micro cantilevers (photo by Jeff Fitlow).

The “diving boards” are a set of microcantilevers, each of which can be decorated with different peptides that have unique binding affinities to strains of the salmonella bacteria. When a peptide catches a bacterium, the cantilever bends ever so slightly, due to a mismatch in surface stress on the top and bottom. A fine laser trained on the mechanism catches that motion and triggers the alarm.  The following picture illustrates the device's structure (photo by Jinghui Wang).

The system is sensitive enough to warn of the presence of a single pathogen, according to the researchers, who wrote that very low pathogen concentrations cause foodborne disease.

The idea springs from research into the use of microcantilevers by Rice biomolecular engineer Sibani Lisa Biswal and lead author Jinghui Wang, a graduate student in her lab. Biswal was prompted to have a look at novel peptides by her graduate school friend, Nitsara Karoonuthaisiri, head of the microarray laboratory at the National Center for Genetic Engineering and Biotechnology in Thailand. Karoonuthaisiri is also a visiting scientist at the Institute for Global Food Security at the Queen’s University, Belfast.

“She’s been working in this area of pathogenic bacteria and asked if we have thought about trying to use our microcantilevers for detection,” Biswal said. “Specifically, she wanted to know if we could try these novel peptides.”

Karoonuthaisiri and her team had isolated bacteriophage viruses associated with salmonella through biopanning and phage display, a technique to study interactions among proteins, peptides and pathogens. She then derived peptides from the phages that would serve as targets for specific bacteria.

“She said, ‘We spend a lot of time trying to characterize which of these peptides work the best. It looks like you have a platform that can do and quantitate that.’ So that’s where we came in,” Biswal said.

The Rice lab compared the peptides’ performance with commercial antibodies now used for salmonella detection and found the peptides were not only more sensitive but could be used in a multiplexed cantilever array to detect many different kinds of salmonella at once.

“The peptides are very robust,” Biswal said. “That’s why a lot of people like them over antibodies. The peptides can handle harsher conditions and are much more stable. Antibodies are large proteins and break down more readily.

“We’re very excited to see where this will lead,” she said.

Co-authors are researcher Josephine Morton and Christopher Elliot, director of the Institute for Global Food Security, and Laura Segatori, Rice’s T.N. Law Assistant Professor of Chemical and Biomolecular Engineering and an assistant professor of biochemistry and cell biology. Biswal is an associate professor of chemical and biomolecular engineering.

The Welch Foundation, a Hamill Innovations Award Grant, the European Union’s Seventh Framework Program and a Marie Curie Fellowship supported the research.

Source: Rice University News & Media

Speed Is Everything When Fighting Sepsis

Lab-on-a-chip promises rapid sepsis detection in newborn babies and opens the door to adapted antibiotic treatment.

Sepsis, commonly known as blood poisoning, is a bacterial infection of the blood. It is dangerous for adults. And it is often mortal for young children, if left untreated. Amongst neonates and premature children the occurrence of sepsis can be as high as 40% to 50%. The most virulent variety can kill within hours. No wonder sepsis is considered one of the most challenging problems when providing medical care to newborn infants. This explains why a fast and effective diagnostic method for sepsis is eagerly awaited, specifically in maternity hospitals. This is exactly what ASCMicroPlat, an EU funded research project, promises. It could then lead to use of effective antibiotics, tailored to the specific type of sepsis identified.

Fast solutions are required. But how fast is fast? In what sense is the new diagnostic technology different from the present day methods? “ASCMicroPlat is, in fact, a lab on a disc, that can identify sepsis up to 20 times faster than present day methods,” says Gregor Czilwik, engineer of microsystems technology, and project manager at HSG-IMIT, in Freiburg, Germany. “We ultimately aim for a fully automated system whereby a drop of blood goes in, a lab technician pushes a button, and two hours later […] the specific type of sepsis is identified,” Czilwik tells Gregor Czilwik estimates that the test would cost around 50 euros a piece, which is similar to the cost of existing tests.

The speed at which this solution operates constitutes a real progress. “These days, the normal diagnostic methods for sepsis take at least a day, usually 48 hours, and can run up to 5 days, “ notes Arie Bos, head of the department of neonatology in the Princess Beatrix Children’s Hospital in Groningen, The Netherlands. “A blood sample needs to be separated in different components,” Bos continues, “then it must be cultivated, often for days, and then analysed. It’s very time consuming.”

Currently, infants suspected of having contracted sepsis, while waiting for the results of the test, are given a preventive dose of broad spectrum antibiotics. “The condition of the patient can worsen visibly within minutes and kill within hours so we couldn’t possibly wait for days,” Bos says. As a result, antibiotics are often administered unnecessarily; an unwanted side effect in view of the ever bigger problem of resistance against antibiotics.

Other experts concurs that this is a much awaited progress. “It would be welcome to be able to give the infant the right type of antibiotics within a few hours,” comments Axel Heep, a German professor of neonatal medicine and paediatrics, working as coordinator of the department of neonatology at the University of Bristol, in the UK. “It will make the treatment much more effective, or to stop medication in case of a false alarm,” he tells

But will the new device indeed be the next gold standard? This remains to be seen. The inventors have proven it can detect the bacteria causing sepsis. And the design is nearly finished. The last phase of the project will be to test it during the summer of 2014 with some 30 sepsis-positive, and 300 sepsis-negative samples that have been collected by partner scientists at Trinity College Dublin. The next step after that would be for the test to be validated through clinical studies in patients.