From the Taranaki Daily News comes a story that is right up my street. Fiona Wallis gave her dog a bone and found it to be giving off an eerie blue light. What could it be? It’s most likely to be coming from bacteria so the questions people are likely to be asking are: what is it, is it dangerous, and how did it get on the dog bone?
What is it?
First off, its not radioactive! I think the light is most likely to be bioluminescence coming from a colony of glowing bacteria and there are many different species it could be. Almost all glowing bacteria live in water; there is only one well-documented species that lives on land. Of the species that live in water, the vast majority either live in or on fish and other creatures (like my favourite the Hawaiian bobtail squid). This will be the reason why you can sometimes see an eerie glow coming from fish if you’ve left it in the fridge for a few days.
The glowing bones in question had been packaged in salty water as one of its preservatives (also known as brine). This suggests to me that the bacteria is one that naturally lives in the sea, as they like high salt environments. An interesting feature of bioluminescence is that it is a chemical reaction that requires oxygen. This means that it won’t be possible to see light from the bones if they are in a sealed pack. But as soon as the package is opened and the bacteria get a whiff of oxygen…
I’ve made contact with the manager of the company that produced the product and he is getting samples to our lab so that we can isolate the bacteria and identify it, so watch this space.
Is it dangerous?
It’s highly unlikely. There are a couple of glowing bacterial species that produce toxins; the soil bacterium Photorhabdus luminescens produces toxins that kill insects, while some strains of Vibrio cholerae, the bacterium that causes cholera, glow. But it’s far more likely is that it is a harmless sea bacterium.
How did it get on the dog bone?
Once we know what the source of the glow is, we can start to figure out how it got on the dog bone. I know the company involved are working with their suppliers to find out exactly where everything came from. My guess would be that somewhere in the process, something has come into contact with either sea water or a product from the sea. Another case of watch this space.
UPDATE 29/09/14: Glowing bone has arrived!
This evening we received one of the glowing bones as well as an unopened packet from the same batch. The bone is indeed glowing (below is a picture from taken on our imaging machine) but it was the only one. None of the three bones in the unopened packet from the same batch number were glowing. We’ve swabbed both sets of bones and we’ll see whether any bacteria grow over the next few days.