Irradiation has long been thought of as a method to make human foods safer by killing harmful pathogens. But Kansas State University research shows that humans may not be the only ones to benefit from this technology.

Joel DeRouchey, graduate research student at Kansas State University, has been studying the effects of feeding nursery pigs spray dried blood meal and animal plasma that has been treated with irradiation. Pigs were fed diets including irradiated spray dried animal plasma immediately after weaning and in the second phase of feeding.

There's no argument that pigs fed the irradiated blood meal as part of their diet had improved performance. (See accompanying sidebar.) Feeding pigs the irradiated blood meal improved efficiency of gain by approximately 11 percent over the group receiving non-irradiated blood meal. Feeding irradiated blood meal improved average daily gain by as much as 24 percent and average daily feed intake by 11 percent.

The question, what caused the feed-to-gain improvement? One possible explanation is that it reduces bacteria, specifically aerobic bacteria. "Irradiation will vastly reduce the amount of aerobic bacteria, which includes E. coli and Salmonella," says DeRouchey.

Researchers tested various irradiation levels and types on the blood meal, but there was no effect on bacteria count or pig performance.
So far, researchers have only irradiated blood meal and a handful of other specialty protein products. More research is needed to determine irradiation's effect on other parts of the swine diet, says DeRouchey. Soybean meal, fish meal and spray-dried whey are other possible application opportunities.

The U.S. Food and Drug Administration has approved irradiation for animal feed, with the ruling appearing in mid-April. There will be a 30-day comment period before a approval becomes official sometime this month.

Once approval is final, feed companies may turn to companies who are already doing large-scale irradiation. For the feed companies this will only cost about 5 cents per pound of total feed, because blood meal is such a small percentage. If feed companies were to implement irradiation as a policy, it should be economical, says DeRouchey. Still, it's not clear how much more companies would be able to charge for feed containing
irradiated blood meal.

"Everyone values gain differently depending on production system goals, so it's hard to estimate what irradiating blood meal could mean for individual operations," says DeRouchey.

On the other hand, maybe there won't be a premium for irradiated feed ingredients. The wild card is how consumers will react to eating pork from pigs that were fed irradiated ingredients.

The process may ultimately enhance food safety, but using radiation to accomplish that goal can be a tough sell to consumers. A similar example can be found in crops employing biotechnology. They provide the best efficiency and environmental safety, but consumers have balked at genetically modified products. At the same time, irradiation of spices, meat products and fruits and vegetables is common. The same could happen with irradiated feed stuffs – only time will tell.

Despite potential drawbacks, irradiation could become a part of food safety measures in the future. The concept is in its infancy and needs more research. Still, irradiated swine diets may become commonplace sooner than you think, says DeRouchey.

"Irradiation could become fairly widespread within the next 10 years. It can be an economical feed management option and I'm confident it will become a practical option," says DeRouchey. "The scope of how popular irradiated feed ingredients becomes will depend on feed and irradiation companies and how they structure the manufacturing process."

How Does Irradiation Perform?

The use of irradiation on blood meal spikes the growth performance of nursery pigs up to 14 days after weaning. The reason is not certain, but with the numbers presented here, the difference is clear.

Pig Performance Regular Blood Meal (pounds) Irradiated Blood Meal (pounds)
Average Daily Gain 0.50 0.62
Average Daily Feed Intake 0.72 0.80
Feed to Gain 1.44 1.29

Source: Joel DeRouchey, Kansas State University