Field of Science

Love is in the air (and microbes too)

With Valentine’s day fast approaching and love being well and truly in the air it got me thinking, could the bacteria we live with be somewhat involved?

The bacteria living in a commensal, symbiotic or sometimes pathogenic relationship with us are often deemed separate organisms that have no influence on humans, be it by matters of the mind, or the heart. We feel in control of our feelings and our minds, how could an organism so tiny, and nowhere near as complex, influence us?
Well, love is often described as an incontrollable feeling that ‘just happens’ and causes us to often do crazy things.
The Hologenome theory states that the host (humans) plus all of its microbiota (bacteria in the gut etc.) is a single unit (I. Z. Rosenberg & E. Rosenberg 2008). This microbiota plays an important role in health and disease within humans. Therefore, this theory of the relationship between us and our bacteria, seems to make sense.
Our own natural scent (body odor) is unique to every one of us. Bacteria feed on the unique, individual proteins on our skin and release these gasses which become our personal scent. We also produce ‘pheromones’ that are different for men and women and also aid in attraction. It may not smell as sweet as the ‘flowered scented’ perfume, but it’s said to play a part in human attraction and love.
Not only can our bacteria influence when we’re ill and how we digest food – they may also be involved in our personalities, and even our love lives!
A study has shown that our gut microbiota and our brain ‘communicate’ which can influence personality and memory (J. F. Cryan & S. M. O’Mahoney 2011). The term ‘gut feeling’ might actually mean something, and your personality is also an attractive tool when looking for love.
It’s not just our personality our gut can influence. Scientists have been able to change the sexual preferences of fruit flies by altering their gut microbiota (G. Sharon et al. 2010). These scientists showed how a certain bacterial species could influence mating. Could this happen to humans? No studies have been done to show how our own microbiota may influence our sexual choice. However, due to all of us having varied diets, and therefore varied microbiota, it could be possible. So our gut bacteria may have a part to play when it comes to finding ‘the one’.

Happy Valentine's Day :-)

I. Z. Rosenberg & E. Rosenberg (2008)

What's lurking in the tomato ketchup?

Turkey breasts, Cucumbers, Korma sauces and now.. Watermelons! It seems no food is safe when it comes to microbial contamination. Barely does a month go by without a contaminated food source lurking somewhere amongst the news headlines.
Taken from

How often does this happen? Are all foods at risk?

Last year Germany's Escherichia coli outbreak was associated with unwashed bean sprouts and caused severe food poisoning (including deaths) in hundreds across Europe (BBC News, 30/05/11). Scotland's Clostridium botulinum outbreak caused two to be hospitalised due to the severe disease Botulism, that was associated with contaminated jars of korma sauce (BBC News, 14/11/11). Last week a Salmonella newport outbreak has caused one death and has been linked to watermelons (BBC News, 02/02/12).

Due to the UK importing a large number of foods from abroad, these food poisoning cases can spread rapidly through the community. Manufacturing large 'bulk' amounts of packaged foods also increases the risks. So, the likely hood of microbes entering the food supply chain is high.
But don't be scared to eat any food again, the majority of these microbes are killed during cooking (e.g. beef and chicken) hence most illnesses occur when either of these are undercooked or contaminated with raw meat.

The Botulism case was due to the type of bacterium present. Clostridium botulinum produces a deadly toxin (poison), this toxin will then remain in the food even if the organism dies. This toxin is so deadly because it attacks the nervous system, causes blurred vision and small quantities can be deadly (1g could kill the whole of the UK population).
In terms of fruit and vegetables, simply washing before cooking/eating is usually all that is required.
Pre-packaged food, particularly food that does not require heating, is where the major problem lies. However, these 'pre-packaged' types of food poisoning rarely occur.

Strict security guards are present in food manufacturing to prevent microbiological contamination and treatments such as pulsed electronic fields, heat and Ultra-violet (UV) treatment are used for ready-to-eat foods.
Samples are regularly checked for contamination and 'food poisoning risk'. The Health Protection Agency (HPA) have a set of guidelines that manufactures must rely on, which provides the minimum total number allowed by each organism (HPA Guidelines, 2008).

With all these measures put in place to prevent food poisoning, in an ideal world it should not happen. However, the food manufacturers can only do so much - they must rely on the public/food outlet to do the rest.

References Salmonella and watermelons (accessed 6/2/12) E.coli outbreak 2011 (accessed 6/2/12) Clostridium botulinum and Korma sauce (accessed 6/2/12) HPA Guidelines for the microbiological quality of some ready-to-eat foods sampled at the point of sale (2000)