October 6,  2020

Nearly half of seafood samples from Istanbul, Turkey, found contaminated with coliform bacteria

Close to half of seafood products collected in Turkey were found to be contaminated with coliform bacteria, according to a study published in the journal, Foodborne Pathogens and Disease.

The samples were gathered from fish wholesale markets, fish markets, fish hawkers and bazaars in Istanbul.

The study examined levels of coliform bacteria, E. coli, Listeria monocytogenes, Vibrio vulnificus and Vibrio cholerae in 700 samples of raw sea fish, raw mussels, raw shrimp and raw squid. These included 400 samples of raw fish such as gilt-head sea bream, sea bass, bluefish and horse mackerel, and 100 from the other types.

The study found that nearly one in five, or 131 of 700 samples, were contaminated with E. coli, 60 with Listeria monocytogenes and 24 with Vibrio vulnificus. Vibrio cholerae was not found.

The number of positive samples for coliform bacteria for raw fish, raw mussels, raw shrimp, and raw squid were 210, 47, 41, and 39 respectively.

E. coli was detected in 67 raw fish samples, 21 raw mussels, 24 raw shrimp and 19 raw squid samples. Listeria monocytogenes was found in 29 samples of raw fish, 16 of raw mussels, 11 of raw shrimp, and four of raw squid.

The number of positive samples for Vibrio vulnificus for raw fish, raw mussels, raw shrimp, and raw squid were 11, nine, four, and zero, respectively.

"When the pathogenicity of Vibrio vulnificus and possible infection results are taken into account, raw mussels sold uncontrolled by fish hawkers are very serious risk factors for public health. Another important danger related to Vibrio vulnificus is that it does not cause appearance, odor and taste disturbances in seafood, such as fish, oysters and mussels from which the agent is isolated," said the study's researchers.

Microbiological quality of seafood can vary depending on environmental conditions, quality of water, water temperature, salinity, distance to residential areas and pollution, natural bacterial flora in water, food consumed by fish, fishing methods and cooling conditions.

Since seafood and fish are susceptible to secondary contamination, the purchasing stage, treatments during the preparation process and consumers' compliance with hygiene rules are important for food safety.

- Food Safety News