12 June 2013 Last updated at 12:40

7 questions on germs

Continue reading the main story

Info

Some people have very bad habits when it comes to hygiene, says the Food Standards Agency. Many eat food that has been on the floor and hardly ever wash their hands. So how much do you know about the dirt and germs around you?

1.) Multiple Choice Question

How long can Salmonella Typhimurium survive on a dry surface in high enough numbers to contaminate food?

1. A week
   
2. Two weeks
   
3. A month
   
4. Six weeks
   

Info

The study also found that Salmonella Typhimurium can be transferred to food almost immediately on contact. This disproves the "five-second rule" that food dropped on the ground will not be contaminated with bacteria if it is picked up very quickly.

2.) Multiple Choice Question

Some of the most germ-ridden surfaces are on public transport. Does a train or a bus have more bacteria?

1. Train
   
2. Bus
   

Info

The average person's hands probably carry at least 3,000 different bacteria belonging to more than 100 species, say researchers. We all have our own unique "bacterial fingerprint", no two hands are alike. That goes for your left and right hand. A person's hands share only 13% of the same bacteria.

3.) Multiple Choice Question

When it comes to work desks, whose has the most germs?

1. Men
   
2. Women
   
3. Both the same
   

Info

While women wash their hands more than men, they have a more diverse selection of germs living on them. Scientists don't know why, but say differences in sweat, hormones and the use of makeup might be involved.

4.) Multiple Choice Question

Which of these groups has been found to have the cleanest hands?

1. Teenagers
   
2. Retired people
   
3. Manual workers
   
4. Professional workers
   

5.) Multiple Choice Question

How many days can you keep leftover food in the fridge before it is no longer safe to eat, according to official advice?

1. Two days
   
2. Four days
   
3. Six days
   
4. Eight days
   

6.) Multiple Choice Question

When it comes to public toilets, which is the cleanest?

1. One closest to the door
   
2. One in the middle
   
3. One furthest from the door
   

7.) Multiple Choice Question

Which part of the body is home to the most diverse number of fungi?

1. Between the eyebrows
   
2. Heel
   
3. Palm
   
4. Ears
   

Answers

1. Salmonella Typhimurium, one of the three main types of salmonella, can survive for up to a month, according to a study by the Department of Food Science and Human Nutrition at Clemson University in the US.
2. Buses are more contaminated with bacteria, according to a study by the Hygiene Centre at the London School of Hygiene and Tropical Medicine. It also found more than one in four commuters has bacteria from faeces on their hands.
3. Women's desks are more germ-ridden than their male colleagues, according to a study conducted by the University of Arizona in the US. Scientists think this is because women tend to have more lotions, tissues and snack items around than men do.
4. It's manual workers, according to a study by Hygiene Centre at the London School of Hygiene and Tropical Medicine. They wash them more.
5. It's two days, according to NHS Choices. It says food can look and smell fine but still be harmful.
6. It's the toilet closest to the door, according to a survey. This toilet consistently has the lowest bacteria levels because it is used less frequently. People want privacy when going to the loo so usually head for a toilet further from the door.
7. It's the heel, which is home to about 80 genus-level types of fungi. The first-ever study of human fungal skin diversity, conducted by researchers at the National Human Genome Research Institute and the National Cancer Institute in the US, found the palm had a moderate number of fungi and between the eyebrows and ears have few. Certain fungi can cause infections.

Your Score

0 - 3 : Very dirty

4 - 6 : A bit grubby

7 - 7 : Spotless

For past quizzes including our weekly news quiz, 7 days 7 questions, expand the grey drop-down below - also available on the Magazine page (and scroll down).

Explore BBC Science to find out more about germs and the human body.

You can follow the Magazine on Twitter and on Facebook