Tag Archive | food safety

Getting up to speed on mycotoxins in Africa: Is optic sorting the solution?

This post is cross-posted from Agrilinks.

Combating mycotoxin contamination is a major frontier in the agricultural development sector. While mycotoxins (a category of toxic fungal metabolites) occur on many crops in many countries, the associated health burden is more visible in Sub-Saharan Africa. If you’re not feeling up-to-speed on mycotoxins in Africa, I highly recommend watching the presentation below by Dr. Rebecca Nelson, Professor of Plant Science at Cornell University. To download the slides used in the presentation click here.


In a 35-minute narrated PowerPoint, Dr. Nelson highlights a number of recent studies examining mycotoxin prevalence in Kenya and the key factors that can influence mold growth and human exposure. Much of the research was conducted via local hammer mills in Kenya, which seem to be ideal sites for researching and managing mycotoxins. In her conclusions, Dr. Nelson proposes broadly-applicable steps that can be taken by consumers, farmers, traders/millers, and policy actors to tackle the mycotoxin problem going forward.

Here are three of my major takeaways from Dr. Nelson’s presentation:

Maize that is sold to market is often more contaminated than maize that a farmer keeps for her family. A study found that among a sample of households in Kenya, maize that the families kept for their own consumption had a 20% chance of exceeding the legal limit for aflatoxin (a notorious mycotoxin). Maize for sale, on the other hand, had a 40% chance of being over the legal limit for aflatoxin. Why such a stark difference? The discrepancy could be due to the particular maize varieties in question: a survey of 100 Kenyan farmers showed a tendency to keep the local varieties of maize (perhaps better-adapted to resist mycotoxins) for own-consumption, and sell the large-grain hybrids. Or, it could be that people simply take better care of maize that they are planning to keep: 50% of farmers surveyed admitted that they took less care in drying and storage for the maize they intended to sell. Another study showed that contamination was higher at mills than in storage, perhaps because farmers selectively sell older maize that will sooner reach its spoilage point.

The human eye can’t discern if maize is contaminated by aflatoxin, but a specialized optical sorting machine can. The fungus that produces aflatoxin can worm its way into the center of a maize kernel, making it undetectable by the eyes of a farmer sorting her crop. Mechanized spectral grain sorting is being tested as a potential way to identify and remove contaminated kernels. An optical sorting machine uses an LED array and sensor to take a spectral image of each kernel, detects specific wavelengths associated with contamination, and jettisons contaminated kernels into a reject pile. In one study, toxic samples were rejected at a rate of 0-25%, while clean samples were rejected at maximum rate of 1%. Hopefully, further studies and technology advances will allow for a higher rejection rate of contaminated kernels.

Hammer mill shops are practical places to enact mycotoxin awareness and reduction programs. Kenyan householders often visit neighborhood hammer mill shops to grind small quantities of maize. These local mills are good places to educate both maize producers and consumers about various mycotoxin mitigation methods. Many mills already have screened tables allowing people to pick out rotten kernels, which are discarded or go to livestock. This type of hand sorting is effective at reducing levels of some types of mycotoxins produced by visible molds, but not at reducing aflatoxin. If mechanized spectral grain sorting were paired with hammer mills, householders could walk away with a cleaner batch of maize to feed their families.

Overall, I am impressed with the quality and creativity of the research performed by the Nelson Lab and its partners. Further economic studies and cost-benefit analyses will help researchers determine the feasibility of optical grain sorting at the local grain mill level.

For more on mycotoxins, check out these resources:

The Basics: Food Safety vs Food Security

My career has focused on issues of both food safety and food security – two concepts that sound extremely similar but are actually quite different. My family members often get them mixed up and can’t remember which is which, so I thought I’d lay out the definitions to help clarify. I’ll be discussing topics within both disciplines on my blog, so best to get the basics out of the way!

Food Safety

The discipline of food safety deals with the proper handling, preparation, and storage of food with the goal of preventing foodborne illness. Foodborne illness (aka “food poisoning”) may be caused by bacteria, viruses, molds, parasites, heavy metals, or contaminants that make our food unsafe to eat. You’ve probably heard of some of the most common foodborne pathogens: Salmonella, E. coli, Norovirus, etc. Food safety standards and processes are very important all along the supply chain from the farm to your table. When a food company discovers that one of its products is unsafe, it may recall that item. Unfortunately, minor food safety incidents are ubiquitous – we’ve all experienced the tummy aches or worse – but standards and inspections are in place in the United States to guard against major issues. Of course, fresh food can never be 100% insulated from pathogens, and so the consumer needs be conscious of some basic safety rules such as proper cooking, storage, and reheating temperatures.

The heading of food safety also includes food defense, which is the protection of our food supply from criminal or terrorist interference.

Food safety resources:

  • FoodSafety.gov – A U.S. federal government site that contains recall information, food poisoning basics, and tips on how to keep your food safe.
  • Food Safety News – A robust online newspaper covering the latest news and views from the food safety beat.
  • Codex Alimentarius – International food safety standards that influence trade.

Fight BAC graphic from the Partnership for Food Safety Education

Food Security

Food security is more closely aligned with what you may think of when you hear the word “hunger.” If you or your household are food secure, you have a consistent, adequate supply of safe and nutritious food for an active lifestyle. If you are food insecure, then you have a limited or uncertain ability to acquire the food you need to be healthy and active.

Food security is generally seen as having four dimensions:

  • Availability – Adequate supply of foodstuffs to meet the population’s needs
  • Access – Ability to purchase/acquire food when needed
  • Utilization – Knowledge of how to prepare and consume food to enhance nutrition and reduce food safety risk
  • Stability – Consistency of the other three dimensions over time

Improving food security is not just a matter of providing food aid to the poor (in the form of actual food or money to purchase food), although this type of aid is very important in times of famine or disaster. International development organizations, governments, and non-profits need to work together to establish good policies, markets, and supply systems that allow all people to produce and/or purchase the food they need. Food security is intimately linked with issues of economic growth, nutrition, and natural resource management, among others.

Although many people think of hunger and food insecurity as problems that reside in developing countries, they are real problems in the United States as well. The U.S. Department of Agriculture estimates that 14.5 percent of American households were food insecure at least some time during the year in 2012.

Once you know the term food security, you will start seeing it frequently. With the Earth’s population expected to reach 9 billion by 2050, it seems like everyone is talking about global food security and how to feed the world (which is fantastic!).

Food security resources:

Habiba Tukhtaeva shows off the vegetables she grew in her family’s kitchen garden with support from Feed the Future.

So how are food safety and food security related? You can’t have true food security without food safety – after all, contaminated or unsafe food is certainly not adequate for a healthy and active lifestyle free from hunger. Poor food safety measures can affect the availability of food, since spoiled/unsafe foods should be removed from the supply chain.

After writing this post, I asked my husband how he would describe the difference between food safety and food security. He responded: “Food safety pertains to making sure my food won’t kill me and food security pertains to whether I have enough of it.” Not too bad, hubby! 🙂