Content and distribution of biogenic amines in Dutch-type hard cheese

Content of biogenic amines (BA; histamine, tyramine, tryptamine, putrescine, 2-phenylethylamine, cadaverine, spermidine, spermine) and counts of microorganisms (total aerobic and facultative anaerobic mesophilic microorganisms, TAC; lactic acid bacteria, LAB; coliforms; total anaerobic microorganisms, TAN; yeasts + moulds), were evaluated within the ripening interval of 1-6 months in Dutch-type hard cheese, produced by two different producers (the cheeses designated as R30 and R45) using pasteurized milk and different starter cultures (designated as R30-FD and R30-CH in the case of the R30 cheeses). The cheeses from the two producers differed in their fat content (30% and 45% of fat in dry matter, respectively). Substantially higher (P < 0.01) contents of tyramine and the sum of biogenic amines were found in the outer-part samples in comparison with the core ones in the R30 cheeses, which corresponded with higher (P < 0.01) TAN counts in this part of the cheese with presumably more favourable growth conditions. Tyramine content increased linearly (P < 0.01) with increasing time of ripening both in R30-FD and R30-CH and R45 cheese, and concentration of this BA in the R45 cheese after 18 weeks of ripening (309.5 mg kg-1) exceeded a toxicological limit. Also putrescine content and sum of all BA increased significantly (P < 0.001) in all cheeses within the ripening interval. Tyramine, putrescine and phenylethylamine contents, and sum of all biogenic amines and sum of polyamines in R45 cheese (299.8, 60.8, 54.3, 419.0 and 63.2 mg kg-1 of the fresh matter, respectively) were significantly higher (P < 0.01) after 22nd week of ripening in comparison with both R30 cheeses (15.7-41.2, 6.0-6.7, 1.0-2.0, 36.4-68.3 and 7.1-7.5 mg kg-1, respectively). However, TAC, TAN and LAB counts tended to be higher (P > 0.05) in R30-FD and R30-CH samples than in R45 cheeses in this time interval. The microbiological analysis based only on basic groups of microorganisms was inconclusive regarding differences in BA content in the cheeses.