Vacuum Packed Foods Can Breed Deadly Bacteria

Those sealed glossy packs of cheeses and lunchmeat on your grocer's shelf can provide a particularly friendly home for nasty bugs that cause food poisoning, new research shows.

Vacuum-packed foods are deprived of oxygen to keep them fresh and boost their shelf life, but the same strategy is a boon for Listeria monocytogenes, a bacterium responsible for a kind of food poisoning that kills 25 percent of the people it infects.

Unlike many other food-borne germs, Listeria can grow even in the cold temperatures of refrigerators.

Avoiding vacuum packaging would lead to other problems with bacterial growth, so I'm not advocating that," food microbiologist Tine Licht told LiveScience. "But our work does help devise models predicting risk of food-borne disease."

Future research can determine genes key to the invasiveness of oxygen-deprived Listeria, Licht added. This in turn could help devise new methods to fight the germ.


SOURCE:
Live Science

This is particularly interesting on quite a few levels.
Not only do we have a bacterium that can survive in the environment that we use to prevent
the growth of all other dangerous bacterium's, but at the same time we are choosing the lesser
of two evils.

Now of course you should try to buy natural and local foods, but there are quite a few foods
that it's not possible to get locally, so we can't just get rid of of vacuum wrapping foods,
however vacuum packing does prevent the majority of other dangerous bacterium from
contaminating the food.

Hopefully we can find a way to annihilate this particular bacterium from our food sources,
possibly through introducing a specific genomal sequence to the inner wrapping.


Comments, Opinions?

I have never even heard of anyone getting sick from this.
It sounds very rare. That doesnt really mean anything though knowing how fast these things can spread.

Im not going to worry about it.

Btw what will it do to you? Kinda like food poisoning I guess, huh?

Originally posted by earth2
Btw what will it do to you? Kinda like food poisoning I guess, huh?

I was curious about that myself, so I Wiki'ied it.

Infection by L. monocytogenes causes the disease listeriosis. The manifestations of listeriosis include septicemia[1], meningitis (or meningoencephalitis)[1], encephalitis[2], corneal ulcer[3], Pneumonia[4], and intrauterine or cervical infections in pregnant women, which may result in spontaneous abortion (2nd/3rd trimester) or stillbirth. Surviving neonates of Fetomaternal Listeriosis may suffer granulomatosis infantiseptica - pyogenic granulomas distributed over the whole body, and may suffer from physical retardation. Influenza-like symptoms, including persistent fever, usually precede the onset of the aforementioned disorders. Gastrointestinal symptoms such as nausea, vomiting, and diarrhea may precede more serious forms of listeriosis or may be the only symptoms expressed. Gastrointestinal symptoms were epidemiologically associated with use of antacids or cimetidine. The onset time to serious forms of listeriosis is unknown but may range from a few days to three weeks. The onset time to gastrointestinal symptoms is unknown but probably exceeds 12 hours.

The infective dose of L. monocytogenes varies with the strain and with the susceptibility of the victim. From cases contracted through raw or supposedly pasteurized milk, one may safely assume that in susceptible persons, fewer than 1,000 total organisms may cause disease. L. monocytogenes may invade the gastrointestinal epithelium. Once the bacterium enters the host's monocytes, macrophages, or polymorphonuclear leukocytes, it becomes blood-borne (septicemic) and can grow. Its presence intracellularly in phagocytic cells also permits access to the brain and probably transplacental migration to the fetus in pregnant women. The pathogenesis of L. monocytogenes centers on its ability to survive and multiply in phagocytic host cells.

Wiki

Sounds pretty nasty, and the article says there is a 25% death rate.

Dear All

Listeria is a common food spoilage organism, so is salmonella, certain bacillus species, clostrida species(botulism) and the list goes on.

What that paper does not say is that refridgerators DO NOT kill bacterial spoilage organisms they merely slow down or halt their growth. They are still there in low numbers. Not numbers high enough to cause a food poisoning infection. If you neutralise (please DO NOT do this) your stomach acid with a dilute alkali solution, of say sodium hydroxide. The infectious does of bacteria can drop as low as 500 cfu (colony forming units). This is an incredibly small number, you may have over 1000,000 colony forming units per milliliter in a solution before you can even see it with the naked eye. So you can see what protection we have naturally in the way we eat and digest our food.

Packaging in a protected environment reduces the growth of many bacterial or other spoilage species, only cleaning and careful handling before packaging reduces the number actually present.

As an interesting point, the soil ( that stuff you see on the outside of organic produce btw) is one of the largest sources of bacteria we have. Including listeria..Another rich source of bugs is human saliva etc...

What that article should have said is that "when lysteria is present" this can happen not that per se it just does. Carefull technologies have been developed to reduce the incidence of infection with listeria in the food in the first place. Without that careful packaging is a waste of time and a paper bag does just as well.

Don't be alarmed guys this is all just pure nature at it's best. Now you are aware of what bacetriologists and microbiologists have been aware of for many many years.

You guys should see what grows on what in my fridge....I know about this stuff and still things get mouldy before I chuck them away....