Recovery of Staphylococcus aureus in Gray Mugil cephalus Roe (Bottarga): Investigation by an Integrated Cultural/Molecular Approach.

In the Mediterranean area, salted and dried roe from the gray Mugil cephalus bottarga represent a speciality food with great commercial value. Bottarga is currently produced by a traditional handmade process and, the risk of human bacterial contamination during its manufacturing is still unknown; in this perspective the foodborne pathogen Staphylococcus aureus could potentially contaminate this product due to poor sanitation or bad handling during processing. The aim of this work is: to evaluate the contamination level of foodborne pathogens at different product manufacturing stages and, in addition, to describe a fast and realizable method for the rapid detection of S. aureus in bottarga samples in the field. A cultural procedure was initially used to investigate the occurrence of S. aureus and the other main foodborne pathogens in bottarga samples at the different manufacturing stages (from roe to final product). In addition, a molecular approach was used to rapidly determine the presence of total bacteria, S. aureus, and its potential toxigenicity. Of the 194 specimens analyzed, we identified: Clostridium perfringens, Enterococcus spp. and Enterobacteriaceae. However, some samples resulted as being contaminated with S. aureus (4% in roe and 8.7% in the final product). During the bottarga manufacturing process, we observed an increase in pathogen levels (from 10(2) to 10(5) CFU/g) in contaminated samples, and entA and entB genotypes were identified. Reconstruction experiments suggest that the fresh roe and the bottarga (not completely dried) could represent a risk for the contamination and growth of pathogen bacteria. Pratical Application Salted and dried roe from Mugil cephalus can be contaminated with different bacteria species, especially on the farm during the manufacturing process. Among the possible contaminants, S. aureus could be a main cause of foodborne illness in this product. A molecular procedure by real-time PCR could be suitable for a rapid and complete analysis of S. aureus in bottarga or other fish roe products.