In total 13 outbreaks of histamine fish poisoning (HFP) have been investigated in the project. Studies have allowed the itemisation of Photobacterium phosphoreum, Morganella morganii-like bacteria and mesophilic Morganella morganii. In addition Rahnella aquattis was identified as the probable cause of histamine formation in one of the outbreaks investigated.
A major finding from the BIOCOM project is the identification a psychrotolerant Morganella morganii-like bacteria and Photobacterium phosphoreum, growing at temperatures as low as 2°C, as being responsible for histamine formation in cold-smoked tuna that caused HFP. This is significant as previously it was assumed that cold storage was effective at preventing histamine formation. During this reporting period the further characterisation of the Morganella morganii-like bacteria through sequence analysis using Multi-locus sequence typing (MLST) indicates that this is in fact a new species and the name of Morganella psychrotolerans has been proposed. Significant work has been undertaken within the project to establish the conditions under which Morganella psychrotolerans will produce levels of histamine capable of causing HFP. Results from this work indicate that histamine formation by these bacteria can be controlled in cold-smoked tuna by modifying the salt content and restricting the temperature and shelf-life.