Survival and Growth of Selected Microorganisms in Khoa During Preparation and Storage

Abstract

The survival of Escherichia coli and Staphylococcus aureus during the production of khoa, a heat concentrated Indian milk‐based product, was investigated. Heat processing of milk containing from 3.6 to 6.5% fat at either 63 or 73C eliminated all E. coli. Under similar processing conditions, S. aureus was recovered, but only when heated in milk at 63C containing 6.5% fat. Potassium sorbate (3000 ppm) appeared more effective in inhibiting the growth of selected yeast and molds in khoa at 7C, compared to ascorbic acid (3000 ppm). Reducing the water activity (aw) of khoa from 0.97 to 0.93 did not appear to enhance the preservative effect. The reduction of E. coli or S. aureus in khoa during prolonged storage at 6–7C, was less than one log cycle, regardless of awor preservative type. Survival of S. aureus in khoa appeared to be enhanced with a decrease in aw. The potential for pathogens to survive in khoa during processing should be taken into consideration when formulating heating protocols.

Foodborne Disease outbreak associated with eating Gaajar Halwa at a Wedding – Palghar District, Maharashtra, India, 2018

“…[ 6 ] S. aureus can grow in khoa under a wide range of conditions. [ 6 , 7 ] In addition, higher microbial loads have been detected in milk products from local vendors compared to registered dairies in India. [ 8 ] Many unauthorized small-scale vendors sell milk products that do not meet food safety regulations for the treatment and storage of milk.…”