AgBioResearch

Growing food crops is tough.

From constantly fluctuating temperatures and weather conditions to increasingly damaging pests and plant diseases, the odds are often stacked against a productive growing season.

Add in the pressure of meeting heavy market demand, and you have a recipe for anxiety. It’s only natural that growers want to get out in front of these obstacles as much as possible, deploying the latest technology to ensure a profitable endeavor.

And while farming is big business with big challenges, the key to greater effectiveness in the field may come from something only seen with a powerful microscope.

Nanotechnology has been a topic of conversation in the scientific sphere for decades, but only recently has it forayed into agriculture. It involves the manipulation of materials at the atomic and molecular levels to perform a desired task.

Nanoparticles currently appear in cosmetics, clothing, paint and many other products for a variety of reasons, including their antimicrobial properties. The market value of nanotechnology products is expected to surpass $4 trillion by 2018.

In agriculture, nanotechnology has been developed in the form of nanocapsules for application of both pesticides and fertilizers.

Additionally, nanosensors monitor soil and plant health. Although not widespread in use yet, agricultural nanotechnologies are on the cutting edge of innovation.

“This is really amazing technology that can be revolutionary for the agriculture industry,” said Wei Zhang, an assistant professor in the Department of Plant, Soil and Microbial Sciences at Michigan State University (MSU). “But it doesn’t come without questions or concerns. These are brand new technologies in some cases, and because they are becoming more pervasive, we need to learn more about them.”

Zhang is leading an MSU research team studying engineered nanoparticles (ENPs) as an emerging environmental contaminant. As more products employ nanotechnology — particularly in agriculture — the concentration of ENPs released into the environment will increase.

The researchers want to know what that means, especially for food safety.

Keeping fresh produce safe

Zhang began studying nanotechnology during his postdoctoral research. A soil physicist, he focused on the movement of nanoparticles in soil and water environments. Upon arrival at the East Lansing campus, he soon became acquainted with the university’s world-renowned plant science community.

“I got to know some of the leading minds in plant science, and I learned that they were interested in nanotechnology and its agricultural applications,” Zhang said. “After some discussion, a group of us came to the conclusion that food safety would be important. We want to understand how ENPs enter the environment and how they are taken in by the plants, but we also need to determine the human health consequences that may come from that.”

Each of the team members assembled by Zhang is a highly respected researcher who brings knowledge in a different area: Sheng Yang He, an MSU University Distinguished Professor and plant pathologist; Hui Li, an associate professor and soil chemist; and Elliot Ryser, a professor and food safety expert.

In 2013, they received funding from MSU Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs). On the basis of preliminary research data from the first year, they applied for funding from the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA).

The Agriculture and Food Research Initiative’s Foundational Program within NIFA cites food safety as one of its priorities.

Unsuccessful in obtaining grant funding in 2014 and 2015, the team kept working to strengthen the proposal. They sought further funding and were eventually awarded a grant from the Discretionary Funding Initiative through the MSU Office of the Vice President for Research and Graduate Studies.

“The seed funding from MSU was crucial to putting together the best possible proposal,” Zhang said. “It was a rigorous application process, but in 2016 we finally secured USDA funding.”

Nearly $500,000 was awarded to the researchers for a three-year project that began in June 2017. The team is conducting tests in three phases on lettuce, tomato and spinach.

“Fresh produce is the best option for our project because it’s minimally processed prior to being consumed,” Zhang said. “Many people want as little processing as possible for fruits and vegetables, but with that would come a higher likelihood of ENPs remaining in the product if it’s treated in the field with nanopesticides.”

The first step is to test the sorption of ENPs by the plants under various scenarios, such as nanopesticide application or irrigation with ENP-containing water. Understanding the interaction between the plant and ENPs will give researchers clues for developing effective remediation strategies.

Several projects investigating nanotechnology have delved into the uptake of ENPs through plant roots. Very few, however, have studied the role of stomata, the tiny pores in plant leaves that allow for respiration.

“The stomata can be quite large relative to ENPs,” Zhang said. “Stomata may be a few microns in diameter, whereas the nanoparticles may be just a couple hundred nanometers. Since 1,000 nanometers equals one micron, it’s not hard to see how the ENPs could enter through that pathway.”

In stage two, the team will evaluate how a series of different food processing washing conditions affect the ability of the plants to soak up ENPs. The outcomes may differ depending on the temperature or the type of sanitizer used.

Finally, after researchers pinpoint the optimum wash water composition, the produce will be cleaned in a processing line where the team will measure the removal of ENPs. This step will ideally allow the group to make food processing recommendations.

“We are in the stage of gathering information,” Zhang said. “Once we get a good idea as to the concentration of ENPs in the plants, we can begin to quantify the potential risks. But it’s important to understand the scale we’re talking about when we refer to nanotechnology. Just because something is present doesn’t mean it’s automatically harmful. That’s why we need to perform risk assessments. This technology has great potential, and it’s our duty to use it responsibly.”

Leveraging MSU's toxicology expertise

MSU is home to a plethora of accomplished food safety and toxicology researchers. To further capitalize on that, university leadership established the Center for Research on Ingredient Safety (CRIS) in 2014.

Michael Holsapple, the CRIS director, has held various positions within academia and the toxicology industry throughout his 30-plus year career.

“MSU is uniquely equipped to offer a powerful voice to the food safety conversation,” said Holsapple, who is also the endowed chair for CRIS. “CRIS can identify the most pressing issues associated with ingredient safety. Because CRIS operates as an independent academic center, we are committed to providing the public with a science-based, unbiased source for information to enable evidence-based decision making.”

CRIS is working in collaboration with more than 20 food, beverage and personal care product organizations, as well as the Grocery Manufacturers Association, on issues such as nanotechnology and its impact on food safety. The focus of CRIS is founded in research, communications and training.

“Much more research is needed to determine the effect on human health of nanomaterials in food,” Holsapple said. “For any technology, we must ensure public safety and improve public discourse about the safe use of such materials in our food supply. That’s why communications is a vital aspect of CRIS. Through research and communications, we can provide insights about both the risks and the benefits of applying nanotechnology to agriculture.

“A good starting point is to recognize that there is already broad consensus that the total amount of pesticides sprayed on agricultural fields could be significantly reduced through the application of nanoparticles. However, while the size of nanoparticles can make them more efficient, it can also make them more unpredictable. We look forward to working with Dr. Zhang and colleagues to better understand the effects of ENPs on the environment and human health.”

Outside of nanotechnology, CRIS currently funds one research project in which three MSU scientists are studying the interaction of dietary fibers, gut bacteria and gastrointestinal health.

The faculty members are Sudin Bhattacharya, an assistant professor in the Department of Biomedical Engineering, Pharmacology and Toxicology; Sarah Comstock, an assistant professor in the Department of Food Science and Human Nutrition; and Adam Moeser, an associate professor and the Matilda R. Wilson Endowed Chair in the Department of Large Animal Clinical Sciences.

The project began in January 2017. In addition, CRIS offers a graduate program for students in Environmental and Integrative Toxicological Sciences. This new educational focus area includes food and ingredient safety and takes advantage of several courses already available at MSU.

“A critical part of CRIS is training new scientists,” Holsapple said. “These students are the future of food safety and toxicology research. They will help to set the direction of the food industry and act as advocates for consumer safety and wellbeing. It’s an important task, and we think that MSU has the opportunity to be at the head of the table.”