Most of the bags tested positive for Serratia, Enterobacter, and Aeromonas, Staphylococcus epidermidis. Pediococcus, Hafnia and Proteus.
Laura Murray, 33, beauty blogger at lelore.com from Faversham, Kent, submitted her blue linen bag, which is just six months old.
The exterior of her bag tested positive for Salmonella, which causes severe food poisoning - diarrhea, fever and vomiting which lasts four to seven days. There are 2,500 admissions to hospital a year in the UK due to salmonella food poisoning
It also tested positive for Klebsiella pneumoniae, a virulent bacteria that causes pneumonia, urinary tract infections, septicemia, meningitis, diarrhea, and soft tissue infections, as well as Enterococcus faecalis -an aggressive pathogen that causes meningitis, endocarditis and septicemia and urinary tract infections.
Meanwhile, the interior of the bag tested positive for Klebsiella pneumoniae - this is the more virulent of the Klebsiella bacteria that causes pneumonia, urinary tract infections, septicemia, meningitis, diarrhea, and soft tissue infections.
It also tested positive for Cronobacter - a particularly nasty bacterium that causes neonatal bacteraemia and necrotising enterocolitis (both of which cause bowel necrosis that leads to 355 deaths of babies every year in the USA), as well as meningitis, and E Coli.
Speaking after the verdict, Laura said: "I'm pretty shocked by the results I must say! I thought I was doing enough by diligently wash my makeup brushes regularly, but it's amazing how much bacteria is around us that we're oblivious to. I will definitely be washing my makeup bag and it's contents much more frequently from now on."
Nicola McCullough, 40, a beauty blogger at strawberryblondebeauty.com from Belfast, gave testers her Orla Kiely bag, which she bought a year ago.
The exterior of the bag tested positive for enterococcus faecalis, cronobacter and pseudomonas, which causes lung infections in immune-compromised patients.
The interior, meanwhile, was found to contain moraxella, which causes lower respiratory tract infections including tracheobronchitis and pneumonia, as well as Pseudomonas and E. coli.
Nicola said was she both horrified and mortified in equal measure, especially as the bag looks so clean.
"While I'm scrupulous about keeping my makeup and brushes clean, I clearly need to wash my actual makeup bag more often... it honestly never occurred to me before. These results make me want to sterilise everything I own immediately," she said.
Ashleigh Dougherty, a 23-year-old beauty PR and blogger (Being Ashleigh) from London, sent in her two-year-old black fluffy bag, which, again, tested positive for all sorts of bacteria, including salmonella, pseudomonas and Pasteurella, which can cause swelling, arthritis and abscesses.
Ashleigh said: "I was super shocked to read what bacteria was on my bag. I thought it would be the perfect bag to test because of the faux fur material it's made from but it's just made me feel very sick in all honesty."
Sophie Cottrell, a 28-year-old beauty blogger (The Beauty Informer) from London, also sent in a handbag, which was 10 months old and tested positive for the likes of cronobacter, enterococcus faecalis and providencia.
"I was shocked by the number of bacteria found both inside and outside of the bag," said Sophie on seeing the results.
"More shocking was the health implications of having that bacteria present. A dirty makeup bag has always just been an inconvenience, causing damage and dirt to my products. I can't believe a dirty makeup bag can potentially damage me. I will be cleaning my bag on a regular basis from now on."
Emma Leslie, Beauty Editor of escentual.com, who commissioned the research, said: 'Most women are totally unaware that their makeup bags and handbags are a breeding ground for deadly bacteria.
"Quite a few of the bags tested positive for Salmonella both on the inside and outside.
"This research has even surprised us and has shown that there is a serious health risk here. If you left food in a bag or near a bag contaminated with Salmonella bacteria there's a good chance you could get seriously ill.
"Also there were several bacteria that caused meningitis and pregnant women or mums with small babies need to take extra care to clean their bags with anti-bacterial wipes on a regular basis."
Discussing the results, Microbiologist Paul Matewele from the London Metropolitan University, said: 'I was really surprised at the high level of bacteria found on the bags and that some of them are extremely virulent pathogens.
"All of the bags tested positive for a large number of bacteria under strict laboratory tests. We swabbed the interior and exterior the bags and it was clear early on that several types of bacteria were present."
Paul said there are two main issues that have arisen out of the research. Firstly, healthy adult women are leaving themselves at risk of getting food poisoning, and secondly there is a threat to young babies, the elderly and immune-compromised hospital patients from these bags.
"The risk of healthy adults catching diseases like meningitis from the bacteria in these bags is low, but if food is kept in these handbags or near make-up bags with Salmonella bacteria, a colony will grow quickly and if this is eaten you would get seriously ill," he said.
