Salsa Secret: Spice identified as strong antibiotic

Researchers have identified a compound in cilantro, a key flavour component of salsa and a variety of other dishes, that kills harmful Salmonella bacteria. It shows promise as a safe, natural food additive that could help prevent foodborne illness, according to a joint study by US and Mexican researchers.

The compound — dodecenal — was isolated from the fresh leaves of cilantro, one of the main ingredients found in salsa, along with tomatoes, onions and green chilies. The compound also is found in the seeds of cilantro. Both leaves and seeds contain about the same amount of dodecenal, but the leaves are used more abundantly in salsa.

In laboratory tests, dodecenal was twice as potent as the commonly used medicinal antibiotic gentamicin at killing Salmonella, a frequent and sometimes deadly cause of foodborne illness, the researchers say. It is the only naturally occurring antibacterial that is more effective than gentamicin against Salmonella, they claim.

“We were surprised that dodecenal was such a potent antibiotic,” says study leader Isao Kubo, PhD, a chemist with the University of California, Berkeley. Most natural antibacterial agents found in food generally have weak activity.

“The study suggests that people should eat more salsa with their food, especially fresh salsa,” Kubo adds.

In addition to dodecenal, about a dozen other antibiotic compounds were isolated from fresh cilantro that show some activity against a variety of harmful bacteria. Salsa likely contains even more antibacterial compounds that have not yet been identified, according to Kubo.

American Chemical Society, May 24, 2004