Asian Institute of Technology Ph.D. candidate Udaya Rathnayaka, a student of food engineering and bioprocess technology at the School of Environment, Resources and Development, says he has found a better way to detect the deadly pathogen salmonella found in chicken meat. Udaya’s peers would seem to agree. His academic presentation on the topic won him top prize at a recent international symposium organized by Sabaragamuwa University, Sri Lanka, from 8 - 12 July.

His presentation titled “Influence of antibiotic treatments on the detection of viable salmonella enterica from inoculated chicken samples by fluorescent in-situ hybridization” was based on earlier doctoral conducted under the supervision of professor Sudip K. Rakshit.

By finding the best and most reliable method to detect viable salmonella, a food-borne bacterial pathogen found in chicken meat products, Udaya won top honors in the symposium’s livestock production category. His talk won out over twelve international presentations from participants from across Asia. Udaya explains his central thesis: “In the study, I compared samples of chicken meat by using the Normal Fluorescent In-Situ Hybridization (FISH) Method with a Modified FISH Method that I developed myself. I then found that the normal FISH method cannot detect whether the salmonella in the chicken meat is actually live or dead. The modified method detects only the living cells. With my modified method, one can tell whether the meat contains living salmonella or not.”

Udaya says food samples can contain live and dead salmonella cells. By relying solely on the normal FISH method, differentiating live cells from dead cells is very difficult. “My method adds one extra step to this method—the antibiotic treatment step, which takes only 30 minutes extra,” he says. “The process is quite fast and takes only seven hours which is much quicker to that the methods currently available, which normally take 2-3 days.”

Udaya said his research provides benefits to both consumers and the manufacturers. He believes that by developing a rapid and reliable process for the detection of live salmonella cells from food samples, consumers will eventually be better protected from potential food poisoning.

The process could also have application for the food processing industry. Manufacturers can lessen the expenses they incur when forced to discard food products containing only dead salmonella cells. Applying this innovative approach, firms only need to discard meat found to contain live salmonella cells. At present, when salmonella can’t be detected, whether in live or dead cells, all meat in generally thrown out as waste. Udaya claims his modified FISH method can save many food manufacturers money. The modified method can be applied to other kinds of food samples, and environmental samples can be analyzed in this way for detection of microorganisms.

Currently Udaya is experimenting and comparing several other methods used in the detection of food-borne microbial pathogens, studying which one is optimal under different conditions. This study will form part of his overall doctoral dissertation.

In receiving the outstanding paper presentation award, the former AIT Student Union President was presented with a gold medal and certificate of recognition. The award is well known in Sri Lanka and should boost Udaya’s prospects to become a university lecturer. Following his graduation from AIT in one year’s time, he plans to return home and resume teaching at the university where he taught prior to enrolling. He hopes to gain promotion as a senior level lecturer, eventually. Udaya received a scholarship from his former university (with support from the World Bank) and a partial fellowship from AIT.