Archives for the month of: June, 2013

Welcome back to our Mycotoxin Series!

Patulin wouldn’t be the first mycotoxin I’d typically introduce, but it has been in the news recently.  Patulin is produced by species of Penicillium, Aspergillus and Byssochlamys, which are filamentous fungi or “molds”.  Patulin can be found contaminating products like fruit, grains and cheese; however, apple juice is of most concern.  And let’s be real, it’s the bruised, damaged and misshapen apples that go into juice (blemish-free are reserved for fresh market’s picky consumers).  However, apples with rot (see below) should NOT go into juice or cider production due to patulin concerns.

apple with Penicillium expansum

Apple infested with Penicillium expansum, a patulin producer.
[NOTE: The blue-gray growth is the fungus. Patulin (waaaaay too small to be seen by the human eye!) is produced by the fungus and spreads into the rotten apple.]

Photo: Puel et al. 2010. Toxins (Basel). 2(4): 613–631.

In April 2013, Winn Dixie brand apple juice was voluntarily recalled due to patulin levels over 50 parts per billion (ppb).  In June 2013, researchers from the University of Granada reported that more than 50% of commercial apple juices tested contained >50 ppb patulin (50 ppb is the “limit” for patulin in both the US and EU).

Healthy apples

Healthy apples

Patulin in apple juice is of particular concern as this product is frequently served to young children.  In fact, some of the commercial juices tested in the aforementioned study were specifically produced and marketed to children. This toxin is a suspected carcinogen and symptoms of a patulin mycotoxicosis (poisoning) are gastro-intestinal inflammation and ulcers, weight loss, swelling, convulsions and impaired immune response (source).

While I’m not a medical doctor or veterinarian, eliminating the contaminated product from one’s diet often alleviates the symptoms.  However, acute mycotoxin poisonings are rare in the US (especially for humans).  Chronic exposure to low levels of mycotoxins is much more concerning and is difficult to study.  Hopefully, juice producers will step up their mycotoxin testing protocols to reduce the levels of patulin on the grocery shelves.

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Optional subtitles: Why should I care? Do I really want to know? Thanks a lot Debbie Downer.

Consumers are becoming increasingly aware of and passionate about food quality and safety.  Not a day goes by that you don’t hear buzz words like “organic”, “GMO”, “hormone-free”, “free range”, etc.  Here in the United States, we have a (relatively) safe and secure supply of food.  However, when that security is compromised, it can be big news:

GMO wheat found in Oregon (2013)

Salmonella (2012) and Listeria (2011) found on cantaloupe

E. coli on salad greens in California (2006)

Over the next few weeks I’d like to talk about another threat that can also sicken humans and animals but doesn’t often receive a lot of press: Mycotoxins.  Mycotoxins are pervasive and fascinating, in my opinion.  However, I did spend much of PhD and post doc studying them…

What is a mycotoxin? “Myco” means fungus and a toxin is a poison; mycotoxins are small compounds produced by some fungi that are harmful to humans and animals in small doses. Symptoms of mycotoxin poisoning in humans and animals are known as mycotoxicoses. Mycotoxins associated with “poisonous mushrooms” are easy enough to avoid (don’t eat them!).  However, mycotoxins are frequently found contaminating food and feed products and are consumed unknowingly.

mycotoxin_katelynwillyerd_wheat

Many species of fungi that produce mycotoxins are also plant pathogens.  As part of their infection and colonization of the plant, they produce these toxins which end up in parts of the plant humans and animals eat. I’ll be profiling specific mycotoxins in the weeks ahead, but (spoiler alert!) some of the crops frequently contaminated with mycotoxins are wheat, corn and peanuts.

Interestingly, we don’t know why fungi produce these toxins.  Hypotheses include antiherbivory (protect a host plant and fungus from being eaten), defense against competitors (a weapon against other fungi or microbes), promotes virulence/aids in causing disease or performs some unknown function in fungal cells.

Stay tuned for more in the Mycotoxin Series.

PS – Fungi are really cool organisms and produce many compounds that have been beneficial for humans, such as dyes, penicillin, statins (for high cholesterol), etc!

The stories I’ve been reading…

But first a gratuitous wheat shot, because I can’t resist those amber waves of grain:

wheat

1. It was reported last week that Monsanto’s Roundup-ready (glyphosate-resistant) wheat was uncovered in Oregon.  The catch?  Monsanto field-tested the wheat nearly 10 years ago but never released it for commercial use.  Roundup-ready corn and soybeans, which are resistant to the herbicide glyphosate, are widely grown in the US. However, these crops are generally processed or used as animal feed, whereas wheat is consumed directly by humans. There is global alarm over genetically modified (GM) foods in our diets and prolonged exposure to these foreign genes. Monsanto dropped the GM wheat project over producers’ trade concerns. As a result of this finding in Oregon, Japan has suspended wheat imports from the Pacific Northwest. Japan is the top importer of US wheat. So far there is no evidence that GM wheat has entered the food supply, but one has wonder if the presence of GM wheat on one Oregon farm is a unique occurrence.

Update: Monsanto is being sued by farmers in the Pacific Northwest over loss of business due to the GM wheat scare.

2. Scientific American reports another contributing factor of honeybee colony collapse may be the alterations to domesticated honeybee diets.  Of course the natural food source of the honeybee is its honey, but when we harvest it for human use the bees are given sugary syrups instead.  Most researchers agree that pesticide use is the predominate cause of colony collapse, but poor nutrition certainly adds to the bees’ stress, I would think.

What have you been reading?