Composting is a process for converting waste into materials beneficial for plant growth through the action of microbes, especially of fungi which can break down large molecules. But fungi involved in composting are not always harmless.
Vidya De Gannes and colleagues show that composts can contain more fungi that are potentially harmful to humans than was previously realized.
Using intensive DNA-sequencing to analyze fungal communities in three different composts of tropical agricultural plant waste, the authors found many fungal species not previously known to occur in composts. These include 15 species of opportunistic pathogens that can cause a variety of diseases, especially in people whose immune system has been weakened.
Intensive DNA-sequencing can therefore serve as a "sentinel" technology to identify a potential health risk, conclude the authors.