酸奶发酵过程中抗生素对酸度的影响

建立7种抗生素对发酵产酸奶的酸度影响。用保加利亚乳杆菌和嗜热链球菌按1∶1菌浓度比来发酵牛奶,NaOH滴定其酸度。结果表明:头孢噻呋钠、青霉素G钾盐、硫酸链霉素、盐酸土霉素、硫氰酸红霉素对发酵生产酸奶的临界质量浓度点分别为0.012 5、0.25、30、0.125和2.5 mg/L;硫酸庆大霉素和磺胺嘧啶的临界质量浓度点高于200 mg/L;抗生素的浓度低于临界浓度点,酸奶的酸度在80°T到100°T之间。实验证明:在酸奶发酵过程中加入抗生素对酸奶酸度的变化趋势稳定,利用酸度来判断抗生素的浓度具有可操作性。

Influence of antibiotics on acidophilus milk acidity during the fermentation

The influence of antibiotics on the acidity of acidophilus milk was investigated in fermentation of milk by using L.bulgaricus and S.thermophilus.The result showed that the critical quality concentrations of five antibiotics,i.e.,ceftiofur sodium,benzylpenicillin potassium,streptomycin sulfate,oxytetracycline,and erythromycin thiocyanate,were 0.012 5,0.25,30,0.125 and 2.5 mg/L,respectively.The critical quality concentration of gentamycin sulfate and sulfadiazine was over 200 mg/L.When the concentration of antibiotics was less than the cretical concentration,the acidity was between 80 and 100.During the fermentation,the changing of antibiotics concentration kept stable according to the changing of acidity.