sample research under hood

Total coliforms and E. coli

Total coliforms and Escherichia coli (E. coli) are two fecal indicator bacteria (FIB) commonly used to monitor microbial water quality. Isolating all pathogens from a waterbody is difficult, so FIBs are used as a proxy measurement. FIB measures the potential of water to contain gastrointestinal pathogens and provides indication of drinking and recreational water safety.

The New Jersey Department of Environmental Protection has established Water Quality Criteria for both drinking and recreational waters. Testing involves taking a water sample to the laboratory, filtering it, and incubating the filtrate to let the bacteria develop colonies. The number of colonies counted at the end of the incubation period allows us to assess water safety. Bottles for bacterial water quality testing must be sterilized prior to collecting the water sample. Sample must be analyzed within a short time after collection; if a sample sits too long, bacteria can begin to grow, which will artificially inflate the number of colonies in the final count. For this reason, it is necessary to work with the laboratory staff to schedule the sampling.

At NJCWST, we are certified by New Jersey Department of Environmental Protection to offer m-coliblue analysis to accurately estimate the E. coli colony forming units (CFU) in surface waters (Total coliforms and Escherichia coli in Water by Membrane Filtration followed by incubation on mColiblue-24 broth).