PROBLEM TO BE SOLVED: To inhibit growth of a strain of the genus Alicyclobacillus which is one of main causatives of deterioration caused by microorganisms in soft drinks, especially highly acidic drinks containing fruit juice and acidic drinks. SOLUTION: Growth of the strain of the genus Alicyclobacillus is controlled or inhibited by adding heat-treated 1,5-D-anhydrofructose to the soft drinks.