Identification of histamine in fish and fish products in Poland during 2014–2018

Histamine is a heterocyclic biogenic amine formed during decarboxylation of amino acids or amination and transamination of aldehydes and ketones (14, 27). This biogenic amine naturally occurs in many species of fish with dark meat, especially of the following families: Scombridae, Clupeidae, Engraulidae, Coryphaenidae, Pomatomidae, and Scomberesocidae (7, 15, 16). Histamine is produced in fish by bacteria secreting the enzyme histidine decarboxylase, especially Morganella morganii and Photobacterium phosphoreum (8, 12, 17). Exposure of fresh fish to elevated temperatures enhances the growth of histidine decarboxylase-producing bacteria, and thus increases the histamine level (19). The purity of ice used to refrigerate fish is also important because it can be a source of histamine-producing bacteria (7).

Histamine is one of the most important biogenic amines in food hygiene because it causes a toxic effect in humans and has been shown to be a potential precursor of carcinogenic N-nitroso compounds (14). Research has demonstrated that fish and fish products containing high concentrations of histamine may pose a health risk to humans if consumed (19). Histamine fish poisoning, also known as scombrotoxic poisoning, is associated with the consumption of contaminated fish of the Scombridae family such as tuna, mackerel, and herring. Food poisoning of this specific type is frequently observed among people at high risk of allergic reaction (11) and intoxicated persons should receive treatment similar to that for seafood allergies (10). The symptoms of scombrotoxic poisoning usually resolve within 24 h, mainly because of a detoxification system in the intestinal tract, which is able to metabolise low amounts of histamine by monoamine and diamine oxidase enzymes (1, 13, 18, 28). However, when there has been intake of a high amount of histamine, this system is unable to eliminate the amine sufficiently (4, 14).

The aim of the present study was to investigate the presence and level of histamine in fish and fish products available in Poland during 2014–2018.

A total of 421 samples of fish and fish products were tested for the presence of histamine. Samples were purchased directly from manufacturers and from various local retail markets in the Puławy region of Poland. The

investigation covered raw fish (248 samples), smoked fish (107), canned fish (50), and marinated fish (16) of the species shown in Tables 1 and 2. After purchasing, the samples were immediately delivered to the laboratory chilled.

Histamine content was determined using high performance liquid chromatography with a diode detector (Varian ProStar 330, the Netherlands) according to the authors’ validated and accredited procedure described previously (21). Briefly, histamine was extracted from samples with trichloroacetic acid and purified using Strata-X-AW ion-exchange SPE cartridges (Phenomenex, Torrance, CA, USA). Chromatographic separation was performed on a C18 column (Agela Technologies, Torrance, CA, USA), with a detection wavelength of λ = 215 nm. The limit of detection was 2.1 mg/kg, limit of quantification was 3.3 mg/kg, and the range of the method was 3.3–420 mg/kg (21).

The results of the histamine analysis in raw fish samples are shown in Table 1. Among the total of 248 such samples, histamine was detected in 35 (14.1%). The concentration of the amine ranged from 3.4 to 156.4 mg/kg, with the highest being found in Atlantic salmon (156.4 mg/kg) and Atlantic herring (42.5 mg/kg). No detectable level of this amine was identified in the remaining 213 raw fish samples tested (Table 1).

Table 2 shows the results of histamine investigation in smoked, canned, and marinated fish. A total of 107 smoked fish samples were examined and in 76 (71%) of them histamine was not detected. In the remaining 31 (29%) samples the content of histamine ranged from 3.5 mg/kg (rainbow trout) to 125.8 mg/kg (European sprat).

Of the 50 samples of canned fish, histamine was identified in 11 (22%) in concentrations from 3.4 mg/kg (Atlantic mackerel) to 17 mg/kg (European sprat and bonito) (Table 2). In marinated fish products (Atlantic herring), histamine was detected in 15 of the total of 16 (93.8%) samples, with the concentration ranging from 4.2 to 122 mg/kg (Table 2).

Among a total of 421 fish and fish product samples tested, histamine was identified in 92 (21.9%). Content of the amine above 100 mg/kg was found in four (1%) samples: raw Atlantic salmon, smoked European sprat and two samples of marinated Atlantic herring (Tables 1 and 2).

Worldwide, histamine fish poisoning is the most frequently involved factor in ichythyotoxicosis and follows the consumption of meat of Scombridae and Scomberesocidae species that contains high levels of histamine (10). The study by Bartholomew et al. (3) showed that histamine content <50 mg/kg did not cause any toxic effect, whereas levels of 50–200 mg/kg are possibly toxic, 200–1000 mg/kg are probably toxic, and >1000 mg/kg are definitely toxic and unsafe for consumers. According to other data, ingestion of food containing a small amount of histamine from 8 to 40 mg can cause slight poisoning symptoms, an amount of over 40 mg results in moderate manifestations, and a dose of 100 mg poisons a person severely (28, 30). Regulation No. 2073/2005 of the European Union Commission of November 15, 2005 on the microbiological criteria for foodstuffs limits the content of histamine in fish and fish products to 100-200 mg/kg (6).

Determination of histamine is important not only due to its toxicity to humans, but also as an indicator of the freshness of fish and fish products (14). Therefore, studies on the content of histamine in food are conducted in many countries around the world. Scombroid poisoning was first described in 1799 in Great Britain and re-emerged in the 1950s when histamine was reported in Japan as a major cause of foodborne disease outbreaks at that time (3, 10). Data available in the Rapid Alert System for Food and Feed (RASFF) reports from 2014–2018 from EU countries show 79 notifications of excessive levels of histamine in fish and fish products. The concentration of histamine ranged from 111 to 6860 mg/kg, and this contamination was mainly in tuna fillets from Spain (22, 23, 24, 25, 26). According to the RASFF annual report for 2014, the majority of histamine notifications were related to fresh or frozen fish stored at insufficiently low temperatures (22). Refrigeration aboard fishing vessels is critical for the control of bacterial histamine formation. Ideally, fish should be kept at 0°C or below to prevent bacteria growth at this temperature histidine decarboxylase is not activated. It has been shown that toxic levels of histamine can be formed during 2-3 h of fish storage at 20°C or higher temperatures (10, 11).

Studies on histamine content in fish and fish products similar to those investigated in the present experiments were carried out in Korea, and this amine was detected in 48.7% of the samples (20). The highest level of histamine was found in anchovies (70.1 mg/kg) and in mackerel (39.3 mg/kg). In a survey conducted in Togo, West Africa, Bouka et al. (5) reported, that 100% of smoked fish samples collected from wholesalers in three different markets contained high amounts of histamine, with mean concentrations of 746.54 mg/kg, 472.37 mg/kg, and 295.06 mg/kg, respectively. This means that none of them met the requirements of the European Commission Regulation No. 2073/2005 (6). In Taiwan, Tsai et al. (29) analysed 61 samples of scombroid fish fillets sold in traditional retail markets, and 6.5% of them contained histamine at concentrations ranging from 128 to 288 mg/kg. In Cape Town, South Africa, histamine levels in fresh fish were low, at 0–9 mg/kg, with the exception of two samples with content above 50 mg/kg (2). Processed fish products also had low histamine concentrations of 0–3 mg/kg, except for 6% of the samples, which contained histamine above 50 mg/kg (2). In a survey conducted in Turkey, Erkan et al. (9) reported, that among 39 canned fish samples from the retail market tested for histamine, 7.7% contained more than 1,000 mg/kg of this amine. In different countries, diverse types of fish contained variable levels of histamine, with higher amounts associated with fish responsible for outbreaks or incidents and lower levels in randomly selected samples (30).

The present study showed that the raw fish and fish products offered on the Polish market generally met the food safety criteria for histamine listed in Commission Regulation (EC) No. 2073/2005 and are safe for consumers. However, our results demonstrate that a few samples contained more of the amine than the legal limit, which made them unsuitable for consumption. The priorities to prevent scombrotoxic poisoning are adequate refrigeration practices, adherence to international standards of food hygiene and appropriate fish processing procedures to prevent bacterial spoilage and the production of histamine (13, 18).