An outbreak of illnesses in Northern Germany caused by a new strain of E. coli has made 1800 people sick with 18 deaths. The New York Times stated that “the outbreak has been particularly virulent because it has led to a potentially lethal complication, known as hemolytic uremic syndrome, or H.U.S., which causes kidney failure and neurological damage.” The Times also reported that, by using an epidemiological study of the pattern of infection, German authorities have concluded that contaminated sprouts from an organic farm were the most likely cause. It is still unknown, however, how the pathogens came in contact with the sprouts.
It’s possible that the public may now become suspicious that biosolids contain harmful E coli. However, testing for fecal coliform has shown that, through proper treatment, pathogenic bacteria in biosolids are reduced to safe levels.
There are many types of E. coli, most of which are harmless. Since a small number do come under scrutiny as dangerous pathogens, biosolids are rigorously monitored for indicator organisms, such as fecal coliform, as a means of determining the potential presence or absence of these disease-causing organisms. The term fecal coliform represents a large group of bacteria, most of which are strains of E. coli.
A WERF project, undertaken by Bucknell University regarding regrowth, odors and sudden increases (ROSI) in indicator organisms in biosolids, is working to quantify fecal coliform levels in biosolids. Various test methods are being trialed, including E. coli test methods, to determine which method results in the most accurate numbers of organisms counted. Testing biosolids directly for pathogens, whether before or after treatment, is not feasible because the pathogens are present in such low numbers that it is impossible to measure them. The indicator organisms that are measured are very robust, much more so than the actual disease-causing organisms. This finding strengthens the EPA’s belief that, if we can destroy fecal coliform, we are certainly destroying pathogens of concern.