{HEAD ~ The presence} of various different microorganisms in {TAIL ~ a single culture} is generally referred to as a mixed culture 
{ HEAD ~ The presence } of various different microorganisms in { TAIL ~ a single culture } is generally referred to as a mixed culture
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH