Detection of diacetyl and acetaldehyde in culture medium
Detection of aldehydes with Schiff's reagent
Schiff's test is a qualitative test for the presence of aldehyde functional groups wherein, a colorless Schiff reagent turns into a characteristic violet color when aldehyde groups are present in the sample added.14 The reaction was performed by adding 500 μL of Schiff's reagent to the 5 mL of medium fermented for 48 h at 30 °C. The media samples were assigned scores between 0 and 5 based on reaction intensity at 5 s after reagent addition, with 0 denoting no acetaldehyde production; 1–3 denoting low production of acetaldehyde, 4 denoting good production of acetaldehyde, and 5 denoting very good production of acetaldehyde. Only samples with high aldehyde content (score 5) were further tested to determine if acetaldehyde was indeed present in high amounts.