Microorganism fingerprinting to pinpoint food contamination in supply chain

Using a spectrometer, the researchers are able to detect undesirable microorganisms in finished products and trace them back.

Track and trace a new method that detects unwanted microorganisms in finished products and traces them back to where they occurred in the food chain is more effective, quicker and economical than current systems, said a group of Norwegian researchers.

The team from Nofima Mat and Elopak said it is the first to develop a process using a 

Fourier Transform Infrared (FTIR) spectroscopy that tests and “fingerprints” product samples as they travel through the various stages of the production process from raw material to the packaging line and beyond.

The second step in fingerprinting technique – which involves building up a unique spectral image of microorganisms – examines the finished products. If it finds a microorganism it compares the profile with ones stored in a database to identify exactly where in the supply chain the bacteria, moulds or yeasts first appeared in the product.

In order to find the source of contamination a high number of samples are taken along the production chain ­ such as raw material, after processing, after packing, after distributing. 

Using the group’s technique, the FTIR instrument is able to gather 100 fingerprints per hour­ meaning the number of samples taken in the field can the field can be quite high. After collecting all fingerprints, we need to fingerprint the spoilt sample(s) found to look for a fingerprint match. Then the software will look for the fingerprint match. By doing that we are able to find the source of the food spoilage ­ be it in the raw material or during processing.

The database fundamental to the system’s efficacy is available from Nofima Mat that compiled spectral readings of various microbes collected from a wide variety of foods, including juice and milk. In this project was developed a database of information about the samples, approximately 20 000 spectral profiles of different microbes are already available. 

The laboratory routines to ensure the readings are tested easily reproducible. Expansion of the database is an on­going task and companies that are interested in the process will be able to develop their own.

Another advantage of the process is its low cost, with the main expense being the FTIR instrument. Consumable are very limited and are very cheap and their cost may reduce by 50 per cent compared with DNA technique such as polymerase chain reaction (PCR).

While acknowledging that several other methods exist to pinpoint contamination sources researchers are convinced theirs is the most cost­ effective solution. It is a very precise and high capacity method, with the additional advantage that technicians don’t need to be specialists in mycology in order to identify such microorganisms.

Source: Spectroscopic characterization of microorganisms by Fourier transform infrared 

microspectroscopy. DOI: 10.1002/bip.20247