Barcoded spores could help track, verify food, say scientists

Researchers in the US have come up with a way to trace the provenance of foods and other products using taggants based on genetically-engineered spores.

The team from Harvard University have developed synthetic, non-viable strains of Bacillus subtilis bacteria and Saccharomyces cerevisiae yeast that carry unique DNA sequences that act like a barcode, allowing them to be identified in the lab.

The barcoded microbial spores (BMS) system could find applications such as tracing supply chains following detection of foodborne pathogens or identifying counterfeit goods, say the scientists, led by Jason Qian of Harvard’s department of systems biology.

Using spores is is ideal because their structures provide strong protection for the genetic material inside they carry, protecting it from being denatured by environmental factors, including high temperatures used in cooking or after going through the wash.

“These barcoded spores provide a durable, specific marker that can be read out quickly with simple equipment,” write the researchers in the journal Science.

That includes SHERLOCK, a new portable, DNA detection tool that uses gene-editing enzyme CRISPR to detect genetic signatures in the field on paper strips with the naked eye – in just a few minutes and without the need for expensive equipment.

Current labelling technologies are often labour-intensive and easy to subvert, particularly in light of complex global supply chains, they maintain.

Other researchers have suggested that use of naturally-occurring microbial signatures could also be used to determine an object’s provenance, but that is problematic because it requires extensive and expensive environmental mapping.

The authors show that BMS can label a range of surfaces and persist for months in real-world conditions. Furthermore, they also demonstrate how the spores can tag objects that come into only brief contact with BMS-labelled surfaces, which could open up forensic surveillance applications.