There’s growing pressure for animal agriculture to change its practices, whether it be utilizing gestation crates or feeding antibiotics, but a new paper cautions that these changes may negatively impact food safety.

pigs-inhumane-350.jpgThe discussion paper released by the Council for Agricultural Science and Technology — a research group that includes the Farm Bureau and the American Veterinary Medical Association —  this week identified some of the factors now being discussed that impact animal health, including: antibiotic use, economies of scale, housing, local production and sustainability.

Scientists have long known there is a link between animal health, stress levels and pathogen shedding, but as CAST and others have noted, more research is needed.

“In addition to overtly ill animals, there is a growing body of evidence showing that chronically, previously, and not visibly ill animals are more likely to be contaminated with foodborne pathogens after processing in the abattoir (slaughterhouse),” the researchers write. “These animals, however, may go unnoticed during antemortem (live animal) inspection, and thus questions arise concerning the potential impacts of these animals entering the food supply on public health risk from foodborne pathogens.”

The paper discusses past research that has found animals under stress or sick for a long period of time are more likely to carry key foodborne pathogens, especially Salmonella. Studies have also shown that animals with abscesses or “other significant lesions” that need extra trimming have a greater chance of being cross-contaminated because of the extra handling required.

Many of the buzzwords being discussed in the food movement, and by an increasing number of consumers: “organic,” “all natural,” “antibiotic-free,” or “pastured” have direct animal health implications — many sustainable food advocates argue that these changes lead to healthier animals. But CAST gives some examples of how these methods could have the opposite effect.

Under organic certification, for example, animals cannot be treated with antibiotics or synthetic worm drugs and if animals are based on pasture, these methods directly impact animal health and how production is managed. According to CAST researchers, “increased exposure to the soil and vermin may increase the prevalence of zoonotic diseases in livestock.”

“Various policy changes may negatively impact animal health, resulting in more marginally or not visibly ill pigs, which tips the scales toward reduced public health,” the authors write. “These proposed changes and their consequences need to be considered carefully.”

The paper looks specifically at some research on the difference between keeping animals indoors vs. outdoors:

“Housing livestock indoors can also provide advantages in managing many foodborne organisms. Because outdoor environments cannot be cleaned or disinfected easily, pathogens can persist in the soil, standing water, outdoor structures, and other micro-environments, infecting successive generations of livestock. Other studies have shown that Campylobacter and Salmonella are more common in chickens having outdoor exposure than in birds raised in conventional indoor housing (cages). Dairy cows were shown to be at greater risk of subclinical mastitis when kept in outdoor environments compared with cows kept in barns. According to several studies, outdoor production can also promote infection of the zoonotic parasite Toxoplasma gondii in poultry and swine. This organism has been related in prenatal infections to death or severe brain and eye damage, especially where the mother has not been previously exposed and acquires an infection during her pregnancy.” (Note: For research citations, see the full study).

Researchers also discuss using antibiotics in animal agriculture, a hot topic in the media:

“Antibiotics have a major, positive effect on improving animal and human health. They are used in human and veterinary medicine to treat and prevent disease. Antibiotic use in food animals is highly regulated by the U.S. Food and Drug Administration. The use of antibiotics in food-animal production, however, raises some concerns about antibiotic resistance in bacteria that could affect the efficacy of antibiotics in the treatment of human infections. Concern about antibiotic resistance is not equivalent to actual risk. Resistant bacteria were present long before antibiotics were discovered and found in many places without livestock exposure.”

The FDA, however, has stated very clearly that certain “injudicious” antibiotic uses in agriculture are a public health risk. In its most recent guidance on the issue, the agency cited dozens of studies on antibiotic use and antibiotic resistance. 

The full CAST paper, “The Direct Relationship between Animal Health and Food Safety Outcomes,” can be read here.


  • Interesting. I agree, I think it would be advisable to research the implications to food safety between large confined animal operations and other forms of livestock management. They need to extend parameters, though.
    For instance, chickens in colony systems, such as those supported in Europe and being promoted as more humane in the US and chickens in battery cages are both raised indoors…but that’s where the similarity ends.
    And the study does not touch on other factors, such as environmental impact of large confined animal operations. The environmental effect impacts on food safety, too, because escaped fecal matter ends up in water systems that are used on fruit and vegetable crops.
    I have an addition concern with a report such as this: that it can be used as a way of blocking effective change, for years. Wrongfully, too, because if the people in the report are saying we need to study how less confined (or open) housing systems can impact on food safety, where are the comparable studies made when people started using large confidence animal operations?
    In other words: why defer to large confined animal operations as the status quo?
    There’s nothing in this report that dissuades me from continuing to fight against the large confined animal operations. The scientists should feel free to now do the work they have should have done decades ago.

  • Archie

    There are a lot of unfounded myths about deplorable conditions in production agriculture to be debunked. There are at least as many hokey myths about salubrious attributes of buzzword “sustainable food” production schemes to be debunked. Far too much opinionated BS floating around out there and far too little objective information to carry on a rational discussion. Too bad that doesn’t stop superficial anti-agriculture know-it-alls profusely misinforming us how to live and work, doesn’t even slow them down.

  • federal microbiologist

    The CAST symposium / seminar session was the latest in a string of such sessions sponsored by industrial food animal production (IFAP)- affiliated organizations that are very, very anxious to delay or stymie efforts to regulate and reduce the applications of bulk antibiotics to CAFOs.
    This March, the National Institute for Animal Agriculture (NIAA) had its own annual meeting, and issued its own white paper, which argues against the imposition of restrictions on antibiotic use in IFAP.
    And the Animal Agriculture Alliance / Animal Health Institute has its own listing of recently produced white papers that make strident arguments in favor of bulk use of antibiotics for IFAP.
    Needless to say, these reports and recommendations issued by the NIAA, AHI, CAST, and other IFAP –affiliated organizations all share some of the same features and findings:
    1. Committee and panel members are almost entirely comprised of land-grant university faculty members in departments of animal and food sciences. These faculty members all regularly collaborate with, and receive grants and consulting fees, from IFAP-affiliated corporations and advocacy groups.
    For example, Iowa State University Department of Animal Science faculty member James Dickson, who recently defended LFTB (aka ‘pink slime’), has received funding from the National Pork Producers.
    And the chair of the NIAA white paper committee on ‘Antibiotic Use in Food Animals’ is Leonard Bull of North Carolina State University, an outspoken proponent of CAFOs and a regular consultant to corporations involved with IFAP.
    Strikingly absent from these industry-friendly panels and committees are NIAID- and NIEHS- funded microbiologists affiliated with medical schools, associated research universities, and schools of public health.
    2. The other major professional group associated with a ‘pro’ stance on bulk antibiotic use in IFAP are Production Medicine veterinarians. These veterinarians adamantly insist that critics of bulk antibiotic use (and IFAP in general) are ‘ignorant’ and ‘misinformed’ about ‘modern agricultural practices’, the implication being that only production medicine DVMs have the knowledge and training to speak with authority on bulk antibiotic use in IFAP. This attitude is well-entrenched at organizations like the AVMA.
    The ironic thing is, the majority of Production Medicine vets don’t ever really treat, or lay hands on, any of the hundreds of pigs or chickens residing in the CAFOs they supervise. It would be utterly ridiculous to suggest to a CAFO owner/operator that he or she pays to have a DVM come out to treat a lesion on one (or ten) of the hundreds of animals residing in their buildings.
    If you don’t believe me, look at the ‘Mercy For Animals’ undercover video of the Iowa Select Farms pig CAFO in Kamrar, Iowa, released in Spring 2011.
    It’s not DVMs who are cutting off piglet tails with tin snips, using dirty scalpels to castrate male piglets, or wrapping gauze around piglet abdomens to keep loops of their intestines from dragging on the shed floor. And needless to say, the older animals in the video footage, with visible lesions and infections, are not going to be cause enough for a DVM to come out to the Kamrar CAFO and administer treatment. Nope, it’s minimum –wage, high-turnover employees who are responsible for ‘maintaining animal health’.
    Organizations like CAST, the NIAA, and the AHI are only going to get more outspoken and vociferous in their opposition to efforts by the public health community to clamp down on bulk use of antibiotics.
    The economic and philosophical structure of IFAP is highly dependent on bulk antibiotics in order to produce units of animal protein at an acceptable profit margin.

  • Mike

    Yeah, recommendations from 1) trained experienced experts in the field are never useful. And recommendations from 2) licensed medical professionals, well those are worse than useless. Give me the hysterical opinion of some crackpot in a tin foil hat digitally amplified on some propaganda mill website — now that’s the sort of recommendation certain to rescue us from ourselves! Viva le absurd foodie movement!!

  • BB

    I agree 100% with fed micro…..well said!

  • Prudence

    Fed Microbiologist is Right On!! The fact is antibiotic use in livestock has created profound resistant bacteria effects on human health — and even the FDA has had to acknowledge same.
    How CAST industry insiders casts dispersions on what constitutes Health in livestock rearing is quite illuminating.
    In their Orwellian model — up is down and inside is out — that is, animals confined by the thousands, cheek by jowl or in stacked cages in fetid windowless steel barns and fed highly medicated rations and water are somehow “healthy” while those in low density situations with access to sunshine and rotated pasture are “unsafe” is quite a twist.
    Here’s a quick and easy experimental test to the healthiness of both SYSTEMS. Choose and equal number of representative CAFO and Organic livestock operations. Stop ALL use (sub-therepeutic and therepeutic) antibiotic use in the CAFOs for the rearing lifespan of the particular animals and record the health outcomes. And do the same for the Organic operations to see which is really healthier…
    WAIT — the Organic operations ALREADY do not use any antibiotics (or hormones and other drugs)…. and the CAFO’s are completely dependent…..

  • ME

    So why do we consider taking the Inspectors away from the Slaughter Lines? There is still diseases? Wake up……….

  • Peg G

    Sheesh, what is with the “food histeria” by some people? They’re so worked up about food that I’m not sure what they could possibly end up eating! Food bourne illnesses have been greatly reduced over the last 50 years but some uninformed people choose to believe that it’s gotten worse. I want to make 2 points: 1. I used to raise pigs outside and those conditions were not a rose garden, rather a muddy, snowy, cold/hot, uncomfortable mess, regardless how hard we tried to keep them comfortable. Now nothing makes me happier than to see my pigs comfortable every day (no matter the weather outside) in my nice, neat, climate controlled CAFO, or pig condo as I call it. If you have never raised pigs yourself then you do not know how much better the new facilities are and have no right to tell me what’s best for my animals. I certainly wouldn’t tell a brain surgeon how to do her job. 2. Antibiotics are expensive so farmers use them sparingly. When an animal is sick we believe it is our duty as their caregiver to help them get well. If an antibiotic is administered through the advice of our Vet, we need to keep records of that and follow strict withdrawal times before those animals can go to market. I would much rather eat an animal who was treated and recovered than an animal that had a lingering illness. Antibiotic resistant bacteria has been around since the beginning of antibiotics. I believe the overuse and incorrect use of antibiotics in and by people have a much bigger part in any resistance issues.

  • This is just CAST returning to its source. CAST was created in 1972 to defend the agricultural use of pesticides against growing public concern after the publication of Rachel Carson’s Silent Spring. Now as public concerns about antibiotic use in animal agriculture is growing CAST can be counted on by industry to defend antibiotic use on farm.
    For anyone interested in CAST and its steadfast role in defending conventional agriculture from change, I recommend reading “A Green and Permanent Land: Ecology and Agriculture in the Twentieth Century” by Randal Beeman and James Pritchard.

  • Thanks for finally talking about >Exploring the Link Between Animal Health and Food Safety <Loved it!