Scientists have developed a new method called steganography by printed arrays of microbes (SPAM) that allows secret messages to be hidden in genetically engineered bacteria.
Developed by chemistry professor David Walt and his team of researchers, this new method uses a variety of Escherichia coli strains modified with fluorescent proteins that glow in seven colours, Discovery News reported.
The secret microbial messages are first grown in Petri dishes. The cultures are then transferred to a thin film and ready to be sent to the desired undercover recipient.
To unlock the message, the recipient must transfer the bacteria to a genetically modified growth medium, which acts as the secret key.
For example, the bacteria could be engineered to react only with a certain antibiotic, therefore allowing the message to only be revealed when in contact with that specific chemical.
If any other chemical key is used the message would be scrambled.