Just as the average consumer is becoming informed on what genetically modified organisms actually are along comes a new potentially harmful product that may be entering our food supply.
Nanoparticles are not a new concept. The term nanoparticle is understood to refer to particles whose dimensions are less than 100 nm. Because of their minute size nanoparticles have different properties than those of larger particles of the same material. For example, for a given volume nanoparticles have a much greater surface area, so they are frequently much more reactive than the bulk material. In addition, even in small quantities nanosilver produces more silver ions than solid silver.
Over the last few years, the use of nanomaterials for water treatment, food packaging, pesticides, cosmetics and other industries has increased. For example, farmers have used silver nanoparticles as a pesticide because of their capability to suppress the growth of harmful organisms. Once again the suggestion of possibly labeling products containing nanoparticles has not been raised, although there is a growing concern that these particles could pose a potential health risk to humans and the environment.
When ingested, nanoparticles pass into the blood and lymph system, circulate through the body and reach potentially sensitive sites such as the spleen, brain, liver and heart.
“More than 1,000 products on the market are nanotechnology-based products,” said Mengshi Lin, associate professor of food science in the MU College of Agriculture, Food and Natural Resources. “This is a concern because we do not know the toxicity of the nanoparticles. Our goal is to detect, identify and quantify these nanoparticles in food and food products and study their toxicity as soon as possible.”
Lin and his research colleagues, including MU scientists Azlin Mustapha and Bongkosh Vardhanabhuti, examined the residue and penetration of silver nanoparticles on pear skin. The scientists immersed the pears in a silver nanoparticle solution similar to pesticide application and then the pears were then washed and rinsed repeatedly. Results showed that four days after the treatment and rinsing, silver nanoparticles were still attached to the skin, and the smaller particles were able to penetrate the skin and reach the pear pulp.
“The penetration of silver nanoparticles is dangerous to consumers because they have the ability to relocate in the human body after digestion,” Lin said. “Therefore, smaller nanoparticles may be more harmful to consumers than larger counterparts.”
The food industry has been revolutionized by the use of nanoparticles to enhance flavors, improve supplement delivery and brighten the color of food. However, the concern is that the use of silver nanoparticles could harm the human body.
“This study provides a promising approach for detecting the contamination of silver nanoparticles in food crops or other agricultural products,” Lin said.
Zhong Zhang, Mengshi Lin, Sha Zhang, Bongkosh Vardhanabhuti. Detection of Aflatoxin M1 in Milk by Dynamic Light Scattering Coupled with Superparamagnetic Beads and Gold Nanoprobes. Journal of Agricultural and Food Chemistry, 2013; 61 (19): 4520 DOI: 10.1021/jf400043z