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Guy Loneragan talks E. coli vaccines in exclusive interview
By Michael Fielding on 4/18/2012
They’re being called the next frontier in the fight against pathogens. Pre-harvest interventions, including probiotics and vaccines, have proven to be effective at cutting levels of E. coli as well as Salmonella.
The incidence of E. coli O157 has dropped dramatically since 1996, and a new study has found that vaccinating livestock prior to slaughter may cut foodborne illness associated with ground beef in half, according to Guy Loneragan, professor of food safety and public heath at Texas Tech University.
He and Scott Hurd, former deputy undersecretary for food safety with FSIS, discussed the results of the study during a webinar sponsored by Meatingplace Wednesday.
Meatingplace spoke at length with Loneragan about his involvement with the development of an E. coli vaccine – and what it will take for it to reach critical mass.
Meatingplace: We’ve talked about pre-harvest interventions as the next frontier of pathogen control. Why have some industry groups only recently turned to pre-harvest interventions as their focus in the last five years or so?
LONERAGAN: It may seem as if pre-harvest interventions are late on the scene, but while most of the attention has been on in-plant interventions, several companies have been working on pre-harvest controls. The pre-harvest ecology of E. coli O157 and control of it within the gut of the animal is highly complex. As a result, it has taken time to successfully translate bench-top discoveries to effective in-field, pre-harvest interventions.
We now have a few quite efficacious tools like probiotics, vaccines and bacteriophages, and in time – we hope – sodium chlorate. [Editor’s note: Since both Salmonella and E. coli are from the same family of bacteria, sodium chlorate may work well against both pathogens. Essentially, the bacteria convert nitrates to nitrite to generate the energy they need. The enzyme used to convert that also converts chlorate to chlorite, which is toxic to bacteria.]
Meatingplace: How does the efficacy of these vaccines look? Are they promising interventions in the near term?
LONERAGAN: We have now several efficacy pre-harvest interventions that include certain strains and dosages of probiotics, vaccines, and bacteriophages. The efficacy of these products is repeatable and, therefore, predictable.
That said, those who are awaiting a silver bullet that can be implemented pre-harvest will be disappointed. The efficacy of these pre-harvest tools, while impressive, is less than 100 percent. What we are really striving for is impact. A moderately effectively product can have a measurable impact if broadly adopted. On the other hand, a 100 percent effective intervention has no impact if left on the shelf.
Meatingplace: The issue of cost can’t be ignored, though. Some reports have put the costs at nearly $10 a shot – with two or three doses required per head. How will that play out along the producer-to-consumer continuum?
LONERAGAN: We all focus on cost, but there’s the other side of that. The benefit. It appears there’s very little benefit for the producers themselves, so any benefit would be downtstream, including the consumer. The challenge is how we share the cost and the benefit. Ultimately we’re going to have to face the consumers and ask if they want product that has received some intervention. The next opportunity is how you affect behavior. We’re connected to each other beyond goods and services through social norms and moral obligations. Those connections are complex between producers and consumers. We need to understand how we can leverage those relationships to impact behavior.
Meatingplace: Why have vaccines gotten the most attention of the pre-harvest options so far?
LONERAGAN: We actually have several efficacious pre-harvest interventions available to us such as specific strains and dosages of probiotics, bacteriophages applied to the hides of animals when they arrive at the slaughterhouse and vaccines. One is conditionally licensed and commercially available in the U.S., and the other is fully licensed in Canada but is awaiting a conditional license in the U.S.
Companies with pioneering technologies take time to work through the somewhat uncharted regulatory pathway. In that sense, the E. coli O157 vaccine that was granted a conditional license by the USDA represents the first regulated vaccine with a label claim to control E. coli O157. This is a major step forward.
Probiotics have no specific label claim for control of E. coli O157, and their efficacy data have never, to my knowledge, been evaluated by a regulatory agency. Regardless, I am convinced the specific probiotics products work effectively and repeatedly – even if it just doesn’t say it on the label.
(For more of the conversation with Loneragan, watch for the May issue of Meatingplace in Print, in which he is featured as our Thought Leader.)