Mikrobiological properties of tofu during the production and storage

S širjenjem znanja o zdravem prehranjevanju in uživanju manjših količin mesa, se soja kot prehranska popestritev jedilnikov vse bolj pogosto pojavlja v svetu in pri nas. V magistrski nalogi smo se osredotočili na sojin sir – tofu. V ta namen so se v obratu za proizvodnjo tofuja mikrobiološko testirale higienske razmere na površinah, v zraku, vodi in tofuju tekom proizvodnje. Ker je tofu zaradi sestave hitro kvarljiv produkt, se je ugotavljal tudi pojav kvarljivcev pri shranjevanju tofuja pri sobni temperaturi. Pri spremljanju rasti bakterij se je opazilo, da se prvih nekaj dni viša število domnevnih enterobakterij, nato pa le-to začne upadati in se viša rast mlečno-kislinskih bakterij iz rodu Lactobacillus spp. Pri mikrobiološkem testiranju tofuja tekom proizvodnje je bilo pri določenih vzorcih opaziti previsoko število domnevnih enterobakterij in aerobnih mezofilnih bakterij, vendar bi za dokončno mnenje morali biti opravljeni še drugi potrditveni testi. Higienske razmere na površinah, v zraku in v vodi pa so načeloma bile, razen nekaj izjem, ustrezne.Increasing awareness about healthy eating and a tendency for a smaller consumption of meat, make soy products to more often appear in our diet. In the present master thesis we have focused mainly on soy cheese – tofu. Therefore, tofu has been microbiologically tested in samples taken from the industrial production line. In addition, hygiene of industrial premices, air and water was also tested. Due to tofu’s nutritional composition, it is a fast spoilage product. To simulate temperature-related inappropriate storage of tofu, spoilage microbiota during storage at room temperature has been determined. While monitoring bacterial growth, it was noticed that in the first days of storage, presumptive Enterobacteriaceae count was rising, followed by its drop and a concomitant increase of lactic acid bacteria, most probably belonging to the genus Lactobacillus spp. During the microbiological examination of tofu sampled from the industrial production line, few samples had a too high count of presumptive Enterobacteriaceae and aerobic mesophylic bacteria, but more tests should have been performed to provide a conclusive opinion. Apart from few exceptions, the production facilities have met hygiene standards on the surfaces, in the air and in the water applied during the production