PL
Celem pracy było określenie jakości mikrobiologicznej wybranych herbat czarnych, zielonych oraz czerwonych dostępnych na rynku stołecznym oraz identyfikacja pleśni wyizolowanych z tych herbat. Część doświadczalna pracy obejmowała przygotowanie zawiesiny herbat, pomiar pH oraz przygotowanie odpowiednich rozcieńczeń do analiz mikrobiologicznych. Badania mikrobiologiczne obejmowały oznaczenie ogólnej liczby drobnoustrojów tlenowych mezofilnych, bakterii z rodziny Enterobacteriaceae oraz grzybów (drożdży i pleśni). W przypadku wyizolowanych pleśni podjęto próbę ich identyfikacji na podstawie dostępnej literatury. Stwierdzono, że wszystkie badane próby herbat były zanieczyszczone drobnoustrojami, jednakże rodzaj mikroflory był zróżnicowany w przypadku każdego rodzaju herbaty. Największym zanieczyszczeniem drobnoustrojami tlenowymi mezofilnymi oraz pleśniami charakteryzowały się herbaty czerwone, w których jednocześnie stwierdzono najmniejszą liczbę bakterii z rodziny Enterobacteriaceae. Największą liczbę drożdży oznaczono zaś w herbatach zielonych. Najczęściej występującym rodzajem pleśni w większości prób herbat był Aspergillus.
EN
Tea, which is the infusion of the tea bush leaves, is now the most popular stimulant in the world. It is interesting due to tradition, history of origin, health properties and the fact that it is one of the few plants still grown in the home regions. From year to year, there is an increase in the consumption of green and red teas, but still black tea reigns on the tables. Despite it is a product with a very low water content, it is not free from microbial contamination. The most common microorganisms in tea are moulds and yeasts. The occurrence of mildew in teas is a fear of the possibility of producing mycotoxins that are dangerous to human health and life. The aim of the work was to determine the microbiological quality of selected black, green and red teas available on the capital market and to identify moulds isolated from these teas. The microbiological analysis of selected black, green and red teas included the preparation of a tea suspension using physiological saline, measuring the pH of this suspension and preparation of appropriate dilutions. They were used to determine the total number of aerobic mesophilic bacteria, bacteria from Enterobacteriaceae family and fungi (yeast and mould). In the case of moulds, an attempt was made to identify them on the basis of available literature. Based on the obtained results, it was found that the lowest pH was characterized by suspensions of black teas, and the highest − red teas. The most varied pH values were found in green teas with fruit (pomegranate, raspberry). The results of microbiological tests indicate that all tested tea samples were contaminated with microorganisms, however, the type of microflora depended on the type of tea. The greatest contamination with mesophilic aerobic bacteria and moulds was found in red teas, in which the lowest number of bacteria from the Enterobacteriaceae family was found. The contamination of tea with bacteria from the Enterobacteriaceae family most probably resulted from a high proportion of human factor during manual harvesting of leaves and activities performed in the production process. The presence of yeast was found primarily in green teas. The most common moulds in the tea trials were moulds of the genus Aspergillus. Their presence is most likely the result of contact of the tea bush leaves with water and air bioaerosols. Summarizing the results, it can be concluded that the key factor affecting the microbiological quality of tea drought is the relatively long-lasting process of their production, occurring at elevated temperatures and aerobic conditions.