Skip to comments.Food fight: Cheese bacteria fight off viral attacks
Posted on 03/22/2007 12:54:42 PM PDT by bd476
Food fight: Cheese bacteria fight off viral attacks
By Julie Steenhuysen
CHICAGO Mar 22, 2007 - Scientists have found a way to ensure starter cultures used to make cheese can ward off attacks from bacteria-eating viruses -- a finding that could mean the difference between a great Gouda and wasted milk.
Attacks by viruses known as phages pose a particular problem for companies like Danish food ingredient maker Danisco, whose starter cultures are used in about half of all the ice cream and cheese produced in the world.
"Phages are one of the major causes of product failure for the food industry, especially in the dairy industry," said Philippe Horvath, a scientist at Danisco's laboratory in Dange-Saint-Romain, France.
The tiny viruses that infect bacteria enter the cell and rapidly replicate until the cell ruptures, spreading the virus in a series of repeating cycles.
"It's an explosive propagation," he said in a telephone interview.
Horvath and colleagues at Danisco have discovered how to harness bacteria's own natural defense mechanisms to produce phage-resistant bacteria. They reported their results in Friday's issue of the journal Science.
The study helps explain the role of a new family of repetitive sequences in the genome of bacteria called CRISPR sequences. They resemble some of the DNA sequences in the phages.
"LET NATURE DO THE WORK"
In computer models, scientists proposed that the CRISPR sequences allow bacteria to hijack a bit of the virus' genetic code, helping it to fight off attacks.
"Our results are the first biological demonstration that CRISPR provides a resistance against phages," Horvath said.
The researchers tested their theory on Streptococcus thermophilus, a bacteria used in making cheese and yogurt.
They were able to manipulate the DNA within the bacteria, adding a new spacer that gave it immunity against the attacking virus.
"We replicated what happens naturally in the lab using molecular biology tools. We've also shown that when we artificially take them out, the bacteria loses resistance," Horvath said.
Although the Danisco researchers could use the finding to produce genetically modified starter cultures for cheese and yogurt, they will not, out of respect for concerns over genetically modified organisms or GMOs in foods.
"We'll let nature do the work for us by simply challenging the bacterium with the phage," he said.
Then, they will simply choose the resistant bacteria for their cell cultures, he said.
This is good news for yogurt and cheese manufacturers. It will probably also benefit the dairy industry as well.
Eat more green cheese!
......Eat more green cheese!....
How about blue cheese!!
I partake precisely because of the bugs that make it blue.
Thanks I'll stick with Swiss or Cheddar.
Yum! I love bleu cheese! Makes wonderful dressing for salad, too...yum-o!
Must be why those of us who post in General/Chat don't get sick as often.
Starter culture for ice cream? Am I missing something? Should I go down to Baskin Robbins and ask for a double scoop of gorgonzola flavored ice cream in a waffle cone?
And you deserve at least 10 points for not mentioning moose or sister.
Me too! BUT- in the last few years I've noticed that blue and Roquefort cheese isn't nearly as BLUE as it was when I was a kid...I even look in the "gourmet" section at Publix hoping to find the real deal...but it's nowhere to be seen.
I'd say "yum" to the gorgonzola flavored ice cream but plain ol' Swiss Chocolate has a better ring to it.
I love cheese!!
It's amazing what goes into cheese.
One of the things that has always intrigued me is that cheese mites are sometimes introduced to cheese to give it the proper flavor. I'm never telling my kids though.
You want imported Danish Blue. Try Sam's Club if none of your local supermarkets carry it. The difference is immense between the imported Danish Blue and any of the domestics. I will go without rather than eat the domestic varieties.
Behold the power of CHEESE!
Sometime I need to post the story of last season's Renfest Cheese-O-Rama. We had six or seven cheeses every night. (I think I spent more money on cheese than I did on my costume.)
"I want to buy some cheese!"
"Oh I thought you were complaining about the music."
"Oh! Heaven forbid! I'm one who delights in all manifestations of the terpsichordian muse."
Cheese mites?? As in bugs??
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