Featured Research

from universities, journals, and other organizations

Small amount of common preservative increases toxins from harmful bacteria in food, study finds

Date:
June 25, 2010
Source:
Lund University
Summary:
In response to consumer demand for more natural food, the food industry has reduced the amount of preservatives in food over recent years. A common preservative is acetic acid, which is used to stop bacterial growth in dressings, sauces, cheese and pickles. However, new research shows that a small amount of acetic acid does not have the intended effect, but rather the opposite -- it increases the amount of toxin from the harmful bacteria in the food.

In response to consumer demand for more natural food, the food industry has reduced the amount of preservatives in food over recent years. A common preservative is acetic acid, which is used to stop bacterial growth in dressings, sauces, cheese and pickles.

Related Articles


However, new research shows that a small amount of acetic acid does not have the intended effect, but rather the opposite -- it increases the amount of toxin from the harmful bacteria in the food.

"In my studies I saw that a small amount of acetic acid caused the bacteria to become stressed, which meant they reacted by producing more toxin. However, if a large amount of acetic acid is added, as was done in the past, the acidity is greatly increased and the bacteria do not survive," explains Nina Wallin Carlquist, Doctor of Philosophy in Engineering at the Division of Applied Microbiology, Lund University.

She recently defended a thesis on the subject, in which she studied two of the most common food poisoning bacteria, Staphylococcus aureus and Campylobacter jejuni.

The Staphylococcus were used in the acetic acid study. A common vehicle for staphylococcal food poisoning is pork meat. Therefore Nina Wallin Carlquist also chose to study how these bacteria behave in different types of pork meat at room temperature: boiled and smoked ham, Serrano ham and salami. The bacteria could get into the food in the first place from an infected cut on the finger of the person who has handled the meat, for example.

Her results show that it only took a few hours for the bacteria to multiply in the boiled and smoked ham. In the Serrano ham, it took a week before the number of bacteria increased and on the salami they did not survive at all.

"A possible explanation is that the bacteria could not survive the salami's combination of acidity, salt, fat and dryness. However, there are other bacteria that thrive on salami. The Serrano ham is manufactured and stored at room temperature over long periods, which means it is important that the staff have good hygiene so that the Staphylococcus cannot get a foothold," comments Nina Wallin Carlquist.

A starting point was to study how the bacteria behave in food. This type of research is otherwise usually carried out in a controlled environment in laboratories where a pure culture of a certain type of bacteria is studied.

According to Nina Wallin Carlquist this provides far from the whole picture because the bacteria are affected by other micro-organisms in the food and also by how much fat, acid and salt the food contains.

"If we know more about what it is in the food that enables the bacteria to thrive, we can then adapt the composition of the food product and thereby improve food safety. This is a new way to approach food safety," explains Nina Wallin Carlquist.

The other bacterium, Campylobacter jejuni, is becoming the next big problem after salmonella. Like salmonella, the bacteria occur naturally in chicken, without harming the host animal.

However, if the contents of the intestines come into contact with the meat during slaughter, the meat can become infected. If the chicken is then not properly cooked the consumer may suffer food poisoning.

"It would be best if the chickens did not get infected with these bacteria to begin with. In my studies I have therefore found out how the bacteria become established in the intestines. In the long term, these results could help in the drawing up of guidelines for hygiene procedures on poultry farms or in developing a vaccine for the animals," says Nina Wallin Carlquist.


Story Source:

The above story is based on materials provided by Lund University. Note: Materials may be edited for content and length.


Cite This Page:

Lund University. "Small amount of common preservative increases toxins from harmful bacteria in food, study finds." ScienceDaily. ScienceDaily, 25 June 2010. <www.sciencedaily.com/releases/2010/06/100624104934.htm>.
Lund University. (2010, June 25). Small amount of common preservative increases toxins from harmful bacteria in food, study finds. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2010/06/100624104934.htm
Lund University. "Small amount of common preservative increases toxins from harmful bacteria in food, study finds." ScienceDaily. www.sciencedaily.com/releases/2010/06/100624104934.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Pygmy Marmoset Getting a Toothbrush Massage Is the Cutest

Pygmy Marmoset Getting a Toothbrush Massage Is the Cutest

Buzz60 (Nov. 19, 2014) This rescued pygmy marmoset named Ninita is obsessed with her toothbrush. It's cuteness overload, and Sean Dowling (@SeanDowlingTV) has the amazing video. Video provided by Buzz60
Powered by NewsLook.com
Why Are Chocolate Makers So Worried?

Why Are Chocolate Makers So Worried?

Reuters - Business Video Online (Nov. 19, 2014) Two big chocolate producers are warning the popular treat could run out by 2020 because people are eating it faster than farmers can grow cocoa. Ciara Lee reports Video provided by Reuters
Powered by NewsLook.com
Tiny Hamster Eating Thanksgiving Meal Breaks the Internet

Tiny Hamster Eating Thanksgiving Meal Breaks the Internet

Buzz60 (Nov. 19, 2014) A tiny hamster and a bunny and rat enjoy a tiny Thanksgiving meal where they stuff themselves to the brim. Sean Dowling (@SeanDowlingTV) has the cute video. Video provided by Buzz60
Powered by NewsLook.com
Giant Panda at Toronto Zoo Loves Somersaulting in the Snow

Giant Panda at Toronto Zoo Loves Somersaulting in the Snow

Buzz60 (Nov. 19, 2014) A giant panda at the Toronto Zoo named Da Mao is celebrating the northeast snowfall by playing and tumbling in the snow in his outdoor enclosure. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins