Campylobacter, E-coli and salmonella – everybody’s heard of them and knows that they’re the bacteria responsible for many food poisoning outbreaks. Staphylococcus aureus is not one that readily trips off the tongue and yet it’s actually classed as a superbug.
If this unpleasant critter gets into your bloodstream you’ll be seriously ill and could even die. As with all serious infections, there are different strains. The most virulent strain of Staphylococcus aureus bacteria is one we’ve all heard of: MRSA. This stands for Methicillin Resistant Staphylococcus Aureus. MRSA is particularly difficult to treat because it’s resistant to many antibiotics.
It’s also really quite easy to contaminate food with Staphylococcus aureus. It occurs naturally on the skin and in the nose of around one-third of all human beings. It can live quite happily on the skin, but if it is allowed to transfer to food, it’s a very different story. That’s why anybody working within the food industry needs to be aware of its presence and how contamination can be prevented.
Which foods are most likely to be contaminated with Staphylococcus aureus?
There are certain types of food that are more susceptible to Staphylococcus aureus contamination than others. These are typically high protein products. Cooked poultry, seafood and egg products can either be handled during preparation or stored at the wrong temperature before consumption. Foods made by hand contact which don’t require any additional cooking are also at risk.
Other examples include cream-filled bakery products. They’re handled whilst the cream in inserted. Another interesting fact about Staphylococcus aureus is that it’s less likely to be found on raw products where several other organisms are present. Because bakery products tend to have a higher sugar content, this inhibits the growth of other organisms, allowing Staphylococcus aureus bacteria to thrive.
Warm temperatures help Staphylococcus aureus to multiply rapidly, so for this reason dry pasta has also been the source of some outbreaks. Additionally, the extrusion equipment used to produce the pasta is difficult to clean creating an ideal environment for the bug.
How to control Staphylococcus aureus
The primary control measures to inhibit the presence and growth potential of Staphylococcus are time and temperature. (You can find out all about this on our Level 3 Food Safety course). However once the bacteria has entered the food and begun to multiply it is practically impossible to eliminate, even by heating to temperatures of over 121°C for several minutes.
Product formulation can also guard against growth of the bacteria. However, since the primary source is staff, personal hygiene is incredibly important in any prevention programme.
How you can help prevent Staphylococcus aureus toxins from forming in food
- Wash hands and under fingernails vigorously with soap and water before handling and preparing food.
- Do not prepare food if you have a nose or eye infection.
- Do not prepare or serve food for others if you have wounds or skin infections on your hands or wrists – this is how Staphylococcus aureus can enter the bloodstream
- Keep kitchens and food-serving areas clean and sanitised.
- If food is prepared more than two hours before serving, keep hot foods hot (over 60° C) and cold foods cold (5°C or under).
- Store cooked food in a wide, shallow container and refrigerate as soon as possible
Typical symptoms and onset period
The average time for someone to experience food poisoning symptoms after consumption of food containing the Staphylococcus aureus toxin is 2 to 4 hours, although it can be as soon as 30 minutes or up to 7 hours. In normal cases it takes 48 hours to recover. Common symptoms transmitted via food are nausea, vomiting, abdominal cramps and diarrhoea.