The Relationship of Histamine Content in European Pilchard (Sardina pilchardus) with Freshness, Temperature, and Storage Duration

Abstract

Histamine food poisoning, stemming from the consumption of certain histamine-rich fish species, such as tuna, mackerel, European pilchards, and herring, is one of the major public health issues worldwide. The present study aimed to evaluate the histamine content in fresh European pilchard (Sardina pilchardus Walbaum, 1792) of Mehdia, a coastal city in the north of Morocco. Three randomly selected batches of fresh European pilchards, each weighing 20kg, were obtained from different boats upon landing. The evolution of histamine production was monitored every 8 hours for 6 days, with one batch stored at 0°C and the other at 10°C. The organoleptic characteristics were examined considering sensory evaluation according to the rating system of European Council Regulation No. 2406/96 as common marketing standards for certain fishery products and the quality index method (QIM). The histamine content in European pilchard flesh was determined using the fluorometric method. The results indicated that the average histamine content did not exceed 5 ppm during storage at 0°C. The freshness ratings were highest during the first 3 days, corresponding to QIM values of 0 to 10 at 0°C. On days 4 and 5, the freshness ratings were on quality A, corresponding to QIM values of 11 and 12, and on the last day, they were on quality B, corresponding to a QIM value of 15 with preservation of the organoleptic quality. Statistically, a significant correlation was found between the European pilchard’s freshness and the storage duration. In contrast, this correlation between the histamine content and the storage duration was insignificant. At 10°C, the average histamine content exceeded the regulatory limit in force (100 ppm) after 32 hours of storage, and spoilage occurred on day 3. Statistical analysis revealed a strong correlation between the histamine content, storage temperature, the degree of freshness, and the duration of storage. The extra freshness quality index of European pilchard guarantees a very large margin of safety regarding histamine and can be consumed without risk. Keywords: Degree freshness, European pilchard, Histamine, Sardine, Storage, Temperature