Microbial and chemical contamination and salt content of smoked fishes produced in Guilan (north of Iran)

Several species of fish are commonly harvested and consumed in north of Iran and distributed elsewhere. Unfortunately, smoked fish is produced traditionally in north of Iran and may become contaminated by carcinogenic metabolites and microorganisms during the smoking process. Additionally, high amount of salt is added to the product to extend its shelf life. Therefore, we aimed to determine both microbial and chemical contaminations and salt content of the smoked fishes produced in Guilan province (north of Iran).

Smoked fish samples (n=20) were collected from five processing units in Guilan. They were transferred to the laboratory under aseptic condition. Microbial tests were included to determination of mold/yeast (by plating method) and Listeria monocytogenes (by polymerase chain reactions). Polycyclic aromatic hydrocarbons (by high liquid chromatography), cadmium and lead (by atomic absorption spectroscopy) were detected as chemical contaminants. Amount of salt was detected by titration method.

None of the samples were contaminated by Listeria monocytogenes, while more than 100 CFU mold/yeast per gram were enumerated in 15% of the smoked fishes. Salt content was calculated as 8.66%. Average concentration of lead, cadmium, and polycyclic aromatic hydrocarbons was 0.082, 0.026, and 0.0036 mg/kg, respectively. Compared to national and international regulations, concentration of the chemical contaminants was within the acceptable range. Although, heavy metals are accumulated in the body and their concentration should be minimized in foods as low as possible. Moreover, more restriction is required with respect to salt because of its role as a risk factor in cardiovascular diseases. To adopt the consumers’ taste, slight reduction in salt content of the products is recommended. In conclusion, there was no serious risk of microbial/chemical contamination in the smoked fishes produced in Guilan. However, their consumption should be controlled in hypertensive patients.