Investigation on Bacterial Growth and pH in Milk after the Expiration Date

Figure 4

Growth curve of bacteria cultured from 2% skim milk samples opened on the day of and up to 10 days after expiration and 0.3 ml milk cultured in 3 ml of 2% agarose gel with 10% FBS in a 60 mm-diameter Petri dish. Colony numbers were counted at 0, 24, 48, 72, and 96 hours after inoculation and presented as the average of 4 plates. Asterisks indicate significant difference compared to cultures collected on the day of expiration (t-test,  < 0.05).