Hello sir
I think they add certain preservatives or follow procedure like heating milk to 90°C for 10 min, cooling to 35°C and adding 0.5% agar agar, incubating with 3% Streptococcus lactis for 16 h at 30°C, heating to 75°C for 10 min, cooling to 30°C, adding 0.1% sodium benzoate, 0.2% potassium sorbate and 6.5% sugar, then filling into sterile glass bottles.
kirti