<Tr> <Td> Cholesterol </Td> <Td> 24 mg </Td> <Td> 32 mg </Td> </Tr> <Tr> <Td> Protein </Td> <Td> 7.9 g </Td> <Td> 9 g </Td> </Tr> <Tr> <Td> Calcium </Td> <Td> 276 mg </Td> <Td> 296 mg </Td> </Tr> <Tr> <Td> Phosphorus </Td> <Td> 222 mg </Td> <Td> 233 mg </Td> </Tr>

Where does the sour taste come from in foods such as cheese and yogurt