Biogenic amines in Spanish beers: differences among breweries

Ten biogenic amines in Spanish beers were studied using HPLC. Agmatine, tyramine and putrescine were the prevailing amines, while histamine,-phenylethylamine, tryptamine, cadaverine, spermine and spermidine were detected at relatively low levels (in general <2 mg/l). On the basis of the wide range of levels observed for tyramine (from 1.90 to 31.55 mg/l), the consumption of beer requires restriction in patients receiving monoamine oxidase inhibitor drugs. Biogenic amine levels in beers of the same type from the same company and from different companies were monitored every month over 1 year. Agmatine and putrescine levels showed minimal fluctuations in beers from the same company as well as from different breweries. Raw materials and brewing conditions would not affect the levels of those amines. However, tyramine levels were subject to wide fluctuations in beers produced by particular breweries irrespective of whether they were produced by the same company. Relatively high levels of tyramine were specific to some breweries.     

Methodological approaches for histamine quantification using derivatization by chloroethylnitrosourea and ELISA measurement. Part II: Optimisation of the derivatization step

In a previous paper (part I), new strategy was used for raising antibodies against hapten (< 300 Da) and the quantification of these hapten by ELISA using derivatization by chloroethyl nitrosourea (CENU). After raising antibodies against histamine, they were characterized and used for ELISA measurements. Optimal detection conditions were determined for the histamine quantification by ELISA method. The present study investigates the derivatization step of the histamine by chloroethylnitrosourea (CENU). Five factors (2 qualitative: nature of the solvent and nature of the antibodies and 3 quantitative: pH, % of solvent and time of derivatization) have been considered. Optimal reaction conditions were established by calculation of a validated model.     

Histamine content and histamine-forming bacteria in mahi-mahi (Coryphaena hippurus) fillets and dried products

Forty-two mahi-mahi fillets and 17 dried products sold in retail markets in Taiwan were tested for histamine and histamine-forming bacteria. The levels of pH, salt content, water content, Aw, TVBN, APC, TC and Escherichia coli in mahi-mahi fillet samples ranged from 5.6 to 6.5, 0.05 to 2.44%, 70.9 to 82.8%, 0.95 to 0.99, 5.9 to 23.5 mg/100 g, 3.1 to 7.0 log CFU/g, <3 to 1650 MPN/g and <3 to 45 MPN/g, respectively. The levels of pH, salt content, water content, Aw, TVBN, APC, TC and E. coli in dried mahi-mahi samples ranged from 5.7 to 6.4, 0.63 to 20.13%, 7.1 to 42.9%, 0.51 to 0.85, 21.4 to 133.9 mg/100 g, 3.6 to 8.7 log CFU/g, <3 to 5900 MPN/g and <3 to 2500 MPN/g, respectively. The average content of various biogenic amines in fillets samples was less than 0.3 mg/100 g. Four of the 17 dried samples (23.4%) had histamine levels greater than the FDA guideline of 5 mg/100 g for scombroid fish and/or product with one of them containing 68.15 mg/100 g of histamine, which is greater than the 50 mg/100 g hazard action level. Eight histamine-producing bacterial isolates, capable of producing 12.6 ppm–562 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH), were identified as Raoultella ornithinolytica (three isolates), Pantoea agglomerans (two isolates), Proteus vulgaris (two isolates) and Enterobacter amnigenus (one isolate), by 16S rDNA sequencing with PCR amplification.     

Histamine production by Raoultella ornithinolytica in canned tuna meat at various storage temperatures

Canned tuna meat was inoculated with Raoultella ornithinolytica at a level of 2.0 log CFU/g (low) or 5.0 log CFU/g (high) and stored at 4, 15, 25, or 37 °C to investigate bacterial growth and formation of total volatile base nitrogen (TVBN) and histamine in canned tuna meat. R. ornithinolytica grew rapidly in all samples stored at temperature above 15 °C regardless of the inoculation levels. The histamine contents quickly increased to higher than 50 mg/100 g within 12 h in the low inoculated samples and stored at 37 °C as well as in those inoculated with the high level and stored at 25 °C or higher. However, growth of R. ornithinolytica and its histamine production were inhibited when samples were stored at 4 °C. The TVBN contents in all samples were all below 30 mg/100 g during storage even when the levels of histamine in some samples increased to greater than 50 mg/100 g. Therefore, canned tuna meat was a good substrate for histamine formation by bacterial histidine decarboxylation at elevated temperatures (> 15 °C) when it is contaminated with R. ornithinolytica.     

A PCR-DGGE method for the identification of histamine-producing bacteria in cheese

Histamine is the biogenic amine (BA) most frequently involved in food poisoning. Cheese is among the foods in which it is most commonly found, and in some of the highest concentrations. Its accumulation in cheese is mainly due to the presence of lactic acid bacteria (LAB) that produce histidine decarboxylase, an enzyme coded by the gene hdcA. This gene has been sequenced in several histamine-producing LAB. This paper reports a new culture-independent method based on PCR-DGGE for detecting and identifying, at the species level, the histaminogenic bacteria present in cheese. Primers were designed based on the hdcA gene sequences available for Gram positive bacteria, and PCR and DGGE optimized in order to differentiate between amplicons corresponding to different histamine-producing species. The proposed method provides a rapid and simple means of detecting and identifying histamine-producing Gram positive bacteria in foods with complex microbial communities, such as cheese.     

Three-dimensional models of histamine H3 receptor antagonist complexes and their pharmacophore

Molecular modeling was used to analyze the binding mode and activities of histamine H₃ receptor antagonists. A model of the H₃ receptor was constructed through homology modeling methods based on the crystal structure of bovine rhodopsin. Known H₃ antagonists were interactively docked into the putative antagonist binding pocket and the resultant model was subjected to molecular mechanics energy minimization and molecular dynamics simulations which included a continuum model of the lipid bilayer and intra- and extracellular aqueous environments surrounding the transmembrane helices. The transmemebrane helices stayed well embedded in the dielectric slab representing the lipid bilayer and the intra- and extracellular loops remain situated in the aqueous solvent region of the model during molecular dynamics simulations of up to 200 ps in duration. A pharmacophore model was calculated by mapping the features common to three active compounds three-dimensionally in space. The 3D pharmacophore model complements our atomistic receptor/ligand modeling. The H₃ antagonist pharmacophore consists of two protonation sites (i.e. basic centers) connected by a central aromatic ring or hydrophobic region. These two basic sites can simultaneously interact with Asp 114 (3.32) in helix III and a Glu 206 (5.46) in helix V which are believed to be the key residues that histamine interacts with to stabilize the receptor in the active state. The interaction with Glu 206 is consistent with the enhanced activity resulting from the additional basic site. In addition to these two salt bridging interactions, the central region of these antagonists contains a lipophilic group, usually an aromatic ring, that is found to interact with several nearby hydrophobic side chains. The picture of antagonist binding provided by these models is consistent with earlier pharmacophore models for H₃ antagonists with some exceptions.     

A survey of biogenic amines in chinese red wines

Eight biogenic amines were analyzed in 38 samples of red wine from five wine-making regions of China. The analysis was carried out by reverse phase high performance liquid chromatography with fluorescence detector and dansyl chloride precolumn derivation. Tryptamine was not found in any of the samples. Putrescine was detected in all samples (100%), followed by phenylethylamine (84.2%), spermidine (60.5%), histamine (57.8%), tyramine (57.8%), cadaverine (47.4%), and spermine (36.8%). In all the samples, the levels of aromatic and heterocyclic amines with toxicological effects were: 0–4.58 mg/l for phenylethylamine, 0–10.51 mg/l for histamine, and 0–9.13 mg/l for tyramine. The amount of histamine and tyramine in most of the samples (94.7%) was less than 8 mg/l. The amines associated with sanitary conditions were also found to be present in a very low range, between 0 and 12.98 mg/l for putrescine, 0 and 19.01 mg/l for cadaverine, respectively. In the case of other amines such as spermine and spermidine, they yielded very low levels varying between 0 and 2.64 mg/l for spermine, 0 and 3.82 mg/l for spermidine, respectively.     

组织电极测定神经递质组胺的研究

研制了一种用猪肾修饰的碳糊电极，线性范围为１×１０－５～４．５×１０－３ｍｏｌ·Ｌ－１，检出下限为２．５×１０－６ｍｏｌ·Ｌ－１，并能较好地抵抗组氨酸的干扰。文章对组胺在电极表面的反应机理作了探讨。     

Biogenic amines in traditional fermented sausages produced in selected European countries

Aminogenesis in traditional fermented sausages produced in Europe was studied during manufacturing process taking into account technological, physico-chemical and microbial factors. Tyramine was the major amine, followed by putrescine and cadaverine, although the occurrence of di-amines was much more variable. By principal component analysis, relationships between aminogenesis and the country of origin, physico-chemical parameters, processing conditions and microbial counts, were not found, probably due to the high dispersion observed in those variables. Therefore, biogenic amines occurred irrespectively of physico-chemical changes and technological conditions applied for sausage manufacture. By cluster analysis, five groups of fermented sausages were identified on the basis of their quantitative and qualitative profile of total biogenic amine content. Group A included products from very low to low total amine content (from not detected to 150 mg/kg); group B, products with moderate levels (from 150 to 350 mg/kg) tyramine being the major amine; group C, also with moderate amine contents but cadaverine being the major amine; and groups D and E, comprising products with high (from 350 to 550 mg/kg) and very high (higher than 550 mg/kg) amine content, respectively. Samples with moderate, high or very high levels of biogenic amines could be considered as products of less quality, and their consumption could be unhealthy for sensitive individuals or for those under classical monoamine oxidase inhibitor drug therapy.