Suchergebnisse

The aim of the study was the monitoring of six biogenic amines (histamine, tyramine, phenylethylamine, tryptamine, putrescine, and cadaverine) and two polyamines (spermidine and spermine) in 30 samples of dairy products purchased in the Czech Republic, namely in 15 samples of mould-ripened cheeses and in 15 samples of smear-ripened cheeses. A further goal was the microbiological analysis of the individual samples of cheeses (total count of microorganisms, number of enterobacteria, enterococci, lactic acid bacteria, yeasts and moulds). The monitored biogenic amines were analyzed by a high performance liquid chromatography equipped with a UV/VIS DAD detector. The amount of enterobacteria in fresh cheese exceeded 105 CFU.g-1. In smear-ripened cheese flavourless (Romadur type), the amount was >103 CFU.g-1 and 104-105 CFU.g-1 in smear-ripened cheese with flavour. Biogenic amines were observed in two groups of blue cheeses (white veined cheese and blue veined cheese) and smear-ripened cheeses. In both groups, there is a possibility of the presence of biogenic amines because the number of microorganisms and concentration of free amino acids increase during ripening. In ten samples of soft smear-ripening acid cheese and in smear-ripened cheese, the total content of biogenic amines were 22-1000 mg.kg-1 and in 5 samples of these cheeses, it was in range 1000-6000 mg.kg-1. The total amount of biogenic amines in the blue cheeses were in range 40-600 mg.kg-1. The presense of the tyramine was observed in the all analysed cheeses. The tyramine producing strains generated more than 900 mg.kg-1 of this biogenic amine. The production of tryptamine in the analysed cheeses was not proved by this study. The results of this study show that biogenic amines and polyamines are common in cheese. However, in some cases, they can pose a significant health danger for consumers. Any legislative control authority does not monitor them, as they are secondary metabolites even though they are potential health risks. © 2014 Potravinarstvo.

The aim of this study was to describe quality changes of eight long-life foods (instant potato purée with milk, instant goulash soup, canned white-type cheese, pre-baked baguette, szeged goulash meal-ready-to-eat, canned chicken meat, pork pate and canned tuna fish) during three-month storage at 4 different temperatures (-18 °C, 5 °C, 23 °C and 40 °C). These temperatures were chosen to simulate various climatic conditions in which these foods could be used to ensure the boarding during crisis situations and military operations to provide high level of sustainability. Foods were assessed in terms of microbiological (total number of aerobic and/or facultative anaerobic mesophilic microorganisms, number of aerobic and anaerobic spore-forming microorganisms, number of enterobacteria, number of yeasts and/or moulds), chemical (pH-values, dry matter, fat, crude protein, ammonia and thiobarbituric acid reactive substances contents), texture profile (hardness) and sensory (appearance, consistency, firmness, flavour and off-flavour) analyses. Microbiological analyses showed expected results with the exception of szeged goulash, pork pate and tuna fish, which, although being sterilised products, contained some counts of bacteria. The decrease of pH-values and increase of dry matter, ammonia and thiobarbituric acid reactive substances contents were observed during the storage of all foods due to prolonged storage time and/or elevated storage temperature. Furthermore, according to texture profile analysis, hardness of cheese and baguette rose as a result of both storage temperature and time. Finally, the highest storage temperature (40 °C) resulted in a deterioration of sensory quality (especially flavour) of most foods; the exceptions were pate and tuna fish which retained good sensory quality throughout 3-month storage at all temperatures. © 2017 Potravinarstvo Slovak Journal of Food Sciences.