A new instrument used to break down chemical compounds in livestock and poultry odor has one ISU professor sniffing his way to a solution for odor problems associated with livestock facilities.

Jacek Koziel, assistant professor in agricultural and biosystems engineering, said everyone knows livestock and poultry facilities are linked with odor, so there is a challenge for engineers to contain the smell.

Koziel’s instrument combines the use of the human nose as a detector with chemical analysis, which allows for the identification of the most smelly compounds responsible for odor, he said.

Koziel said he identifies the smell of a chemical compound found in livestock or poultry odor by associating it to a smell with which he is already familiar.

A panel of 64 different characteristic smells allow Koziel to choose which smell the odor most resembles, he said.

“By separating the smells, we can easily identify different smells and correspond them with different compounds,” said Miranda Lo, graduate student in agricultural and biosystems engineering.

The “smell scale” ranges from stinky to pleasant, she said. The swine manure panel includes familiar smells like citrus, grass, burnt tires, rotten eggs, buttery, piggy and others, Koziel said.

“What I’m finding out is that not all smells in livestock or poultry manure odor are bad — some actually smell quite neutral or pleasant. However, they are a minority,” Koziel said.

Koziel said the project focuses on identifying the most odorous compounds, but the instrument could be used for other purposes. It was historically used by cosmetic companies, he said.

Although it can be used for consumer and food products, Koziel said the instrument has allowed for progress in the manure odor area.

Originally, it was confusing to pinpoint where the odor problem is because there are many compounds responsible for making characteristic smells present in very low concentrations, he said.

“It’s almost like pulling a needle out of a haystack, because there are so many compounds in the odor but not all of them are important,” he said.

Koziel said it was very difficult to identify odors solely by a chemical analysis and, as a result key, chemicals at low concentrations were entirely missed.

The combination of chemical and smell analysis allows Koziel to discover new compounds responsible for odor that were often overlooked before, he said.

“We are learning that livestock and poultry odors are composed of hundreds, if not thousands, of compounds,” Koziel said.

A lot has been learned during the last year, including a tremendous amount of information about beef and swine odor, he said.

“Most compounds that cause the odor are generated from manure, but we are finding that in a big picture there are many sources on a farm,” Koziel said.

The farm sources may include manure, manure storage, barns and feed storage, he said.

In order to solve livestock and poultry odor problems, there are three steps that must be followed, he said.

The first step is to identify what the most odorous compounds are.

The second step is to develop analytical and olfactory methods to target the compounds that matter, and the last step is to develop and evaluate odor control approaches targeting compounds that really matter, he said.