Certain metals are known to inhibit microbial growth, such as Zinc, Copper and Silver
Silver Nanoparticles have been approved by the FDA for use in food packaging.They are very effective in killing viral, bacterial and fungal microorganisms.
Silver ions control bacteria by means of a triple mechanism:
The fact that the silver acts on the atomic level – oxygen inhibition, at the DNA level and at the cell membrane level make it very effective.
It is true that silver nanoparticles do not cause food borne disease, but the question is whether the silver weaken our body over the long term making us susceptible to other diseases in the future?.
A recently published study by researchers at the University of Southern Denmark showed that silver nanoparticles are able to enter human cells, producing potentially harmful free radicals and changes in certain cellular proteins.
The researchers, led by Professor Frank ie Kjeldsen and Dr. Thiago Verano Brava, studied the effect of two sizes (100 nm and 20 nm) of silver nanoparticles on human intestinal cells in cultures in the laboratory. They used a variety of techniques to examine the interactions between particles and proteins in cells.
The results showed that, although the two particle sizes produce a response, only smaller particles are able to enter cells and cause direct effects. These include the production of reactive oxygen species and the carbonylation of proteins as well as stimulating the production of certain proteins.
" We can confirm that the nano-silver lead to the formation of harmful substances called free radicals in cells. We can also see that there are changes in the form and amount of protein.This worries us , " say Kjeldsen and Verano Brava.
Silver nanoparticles are used as antimicrobial component in certain types of food packaging and are also sold as a dietary supplement in some markets. The Danish Veterinary and Food Administration would have responded to this study cautioning against taking these supplements that are available for sale on the Internet.
Another study suggests silver nanoparticles, used as a pesticide and in some food packaging, could remain on fresh produce after washing, posing potential risk.
When Mengshi Lin and his colleagues doused pears in silver nanoparticles to mimic what happens on farms, some nanoparticles remained stuck on pears four days after repeated washing — and smaller slivers penetrated the pear skin to reach the pulp. That's potentially "dangerous to consumers," said Lin, whose study suggests a method that could be used to detect nanoparticles in food since the smallest slivers could migrate through the body and reach sensitive sites such as the brain or heart.
Besides the possibility of causing harm to our body the silver nanoparticles have the potential to kill off the bacteria in our stomach that help our immune system and our digestion. I believe that there needs to be more research before we use silver nanoparticles on our food.