Detecting Histamine in Your Fish — Chromatography Investigates

In the United States it is estimated that almost 40% of seafood related food illnesses are due to excessive levels of histamine in the flesh of the fish. But now, research supported by Oregon State University have come up with a potentially simple and cheap method of detecting histamine levels in fish.

Histamine in fish, cheese and beer — no sneezing matter

Histamine is a naturally occurring compound — we rely on histamine to help our immune system repel attackers. But too much can cause an allergic reaction — hence, we take anti-histamines to calm down the reaction to those pesky pollen invaders. Fish are an important source of protein — and we are encouraged to eat fish as part of our diet.

But, where there are proteins there are amino acids — proteins are built from amino acids. One such amino acid is histidine. Histamine is produced when histidine breaks down. This can happen in fermentation reactions and decay. Products like soy sauce, red wine and beer all contain histamine, it is part of the natural process of their manufacture. But, the histamine in fish is due to poor storage and handling conditions of the fish after death.

Fossilized algae — makes brighter samples

The work carried out by the Oregon State University and reported in the journal Materials — Diatomite Photonic Crystals for Facile On-Chip Chromatography and Sensing of Harmful Ingredients from Food — made use of a substance called diatomite. Diatomite is made from the fossilized walls of algae and gold nanoparticles. Diatomite is a type of bio-silica that has nanopores and can act like a photonic crystal. This means it can enhance the signal coming from a sample and allow more sensitive detection limits.

The researchers used the diatomite on the surface of thin-layer chromatography (TLC) plates to help separate the samples and then used surface-enhanced Raman spectroscopy (SERS) as the detection system. Chromatography is commonly used to analyse food samples as discussed in this article, Utilisation of LC/MSMS (QTRAP) and Polarity Switching for the Quantitative Analysis of Over 300 Pesticides in Crude QuEChERS Extracts from Various Fruit and Vegetable Matrices. In a press release from the Oregon State University, one of the lead scientists Alan Wang said:

“In tandem, SERS and TLC can create a powerful method for on-site identification of contaminants that is simple and fast and requires no complicated sample preprocessing.”

Detecting histamine

Histamine can be difficult to detect as the background components of the food can hide signals. Physically, it has no smell and doesn’t alter the taste of the fish — so it must be detected at the processing stage. Again, Wang said:

“The gold nanoparticles and the diatomite layer supply nearly 10 times the SERS signal intensity compared to a common silica gel chromatography plate. We made a simple and inexpensive device to isolate and identify contaminants. This on-chip device can be applied as a cheap and robust biosensor for monitoring a variety of harmful ingredients in food samples.”