They have used tetrazolium salt (MTT) to reduce the time taken to measure the number of viable bacteria in food electrochemically from two days to approximately one hour, irrespective of the bacterial species.

The technique can reportedly verify food safety before shipment from factories and prevent food poisoning – a major breakthrough, they note. 

WHO states that food safety, nutrition and food security are inextricably linked, with an estimated 600 million people falling ill and 420,000 dying each year due to contaminated food consumption. 

Food safety and hygiene in the food industry is of paramount importance.

“In this study, we focused on the electrochemical properties of tetrazolium salts and developed a simple method for evaluating viable bacterial counts as an indicator of hygiene control in food and pharmaceutical production sites,” Dr. Hiroshi Shiigi, professor and research lead at the Department of Applied Chemistry, Osaka Metropolitan University tells Food Ingredients First.

Ensuring food safety in time
The researchers flag that the technique can confirm the safety of food products before they leave the factory and prevent food poisoning.

“One of the most important assessment indicators for ensuring that food is free from contamination is the number of viable bacteria. However, conventional measurement methods take up to two days to yield results, and these results are only available after the food has been shipped from the factory—leading to potentially fatal consequences,” explains Dr. Shiigi.

“Therefore, it is imperative to have a testing method that speeds up the process of identifying bacterial contamination before shipment,” he adds.

According to Dr. Shiigi, the team will continue to optimize the measurement conditions and expect to see the “development of a portable sensor” in line with the development of research aimed at practical applications.

Notably, the method does not require complicated operations or expensive equipment. 

Meanwhile, scientists have found that Australian essential oils with antimicrobial properties can prevent food spoilage and address food safety concerns.

Recently, Food Ingredients First reported Corbion’s new online model that predicts time-to-visible mold growth in bread that targets food waste and food safety. 

Dr. Hiroshi Shiigi, professor and research lead at the Department of Applied Chemistry, Osaka Metropolitan University with his research team.

A marketable future
The scientist flags that MTT, a water-soluble molecule, has excellent cell membrane permeability and changes into insoluble reduced formazan inside the cell.

“The number of viable bacteria can be estimated by focusing on the reduction current of MTT remaining in the suspension,” says Dr. Shiigi.

Further, he notes that the standard MTT assay is used as a colorimetric method but requires sufficient incubation time to obtain absorbance. The team found that MTT has electrochemical activity and by “focusing on its current response, highly sensitive measurement became possible.”

The research team has developed the technique based on opinions obtained from interviews with several food product manufacturers in Japan.

“We believe that the product is highly marketable. The plan is to proceed with development with a focus on device realization in the future,” he concludes.