Fermented tofu testing

Fermented bean curd testing covers several key aspects:

Microbiological indicators: Testing of total bacteria, Escherichia coli, Staphylococcus aureus, Salmonella, etc., to ensure food safety and prevent foodborne diseases caused by excessive microorganisms. The culture and counting methods specified in national standards are usually used.

Physical and chemical indicators: Determination of protein content, which is related to nutritional value, using the Kjeldahl method; fat content also needs to be known, often tested by Soxhlet extraction; salt content affects taste and preservation, which can be measured by silver nitrate titration; and pH value, measured by an acidometer, reflects the degree of fermentation and quality stability.

Sensory indicators: From the appearance and color, it should have the inherent color of the variety, such as red fermented bean curd is red, white fermented bean curd is white, and the color is uniform; the texture should be delicate and soft, without lumps or impurities; in terms of smell and taste, it should exude a unique fermented aroma, without peculiar smell, and be moderately salty and fresh in the mouth, with a long aftertaste.

Additive detection: Check whether preservatives, pigments, etc. are added in violation of regulations to ensure compliance with food safety regulations, and use instrumental analysis methods such as high-performance liquid chromatography to accurately identify.