Effects of Sodium Bicarbonate on milk preservation

Abstract

The present investigation was carried out to assess the effect of sodium bicarbonate (NaHCO₃) on the keeping quality of raw cow milk. Milk samples were collected from Bangladesh Agricultural University (BAU) Dairy Farm and initial quality were evaluated using physical and chemical tests at Dairy Technology Laboratory of the Department of Dairy Science, BAU. Then, collected samples were preserved at room temperature (28- 30^°C) with 0.0 (control), 0.3, 0.4 and 0.5 per cent NaCHO₃. The quality of milk samples were measured at every two hours interval up to 6 hours, one hour interval upto 16 hours and thereafter every half an hour interval until spoilage. Initially, colour, flavour and texture of all milk samples were normal (100%), but with progressive storage time colour, flavour and texture of all samples deteriorated gradually, which was more rapid for control samples than that of the NaHCO3 treated samples. Acidity per cent of all samples increased gradually during storage period and the differences in acidity of milk samples in different treatments were significant (p<0.01). Control samples spoiled after 11¼th hours but that of 0.3, 0.4 and 0.5 percent NaHCO₃ treated samples spoiled after 16¾^th, 17¾^th and 18¾^th hours,, respectively. It may be concluded that NaHCO₃ is the effective chemical neutralizing the acids produced by acid producing bacteria and can be used as a short term preservation of milk under rural condition of Bangladesh where scientific cooling or pasteurization facilities are not available.

Res. Agric., Livest. Fish.5(1): 75-85, April 2018