Application of cold- and heat-adapted Lactobacillus acidophilus in the manufacture of ice cream

Manufacture of ice cream using cold- and heat-adapted Lactobacillus acidophilus was studied. Temperature–time combinations at 4 °C for 18 h and at 45 °C for 15 min were set as the adaptation conditions for below and above the optimum growth temperature (37 °C), respectively. Ice cream was produced by two different methods: method 1, ice cream mix was fermented with cold- and heat-adapted L. acidophilus prior to freezing; method 2, cold- and heat-adapted L. acidophilus was added to ice cream mix but the mix was not fermented with L. acidophilus prior to freezing. The lowest reduction ratio was found in the samples produced by using method 1 and cold-adapted L. acidophilus, adapted at 4 °C for 18 h. L. acidophilus survived at the required levels (>106 cfu g−1), with or without an adaptation. The adaptation conditions improved stability of L. acidophilus in the samples, but the magnitude of improvement was small.