Study of Yili Lactoferrin ShuHua Milk in the Improvement of Human Immunization

Inclusion Criteria: * Age 6 to 12 years, catch cold for 4 to 6 times in last year; * Age 35 to 45 years, catch cold for 4 to 6 times in recent 3 month; * Age 60 to 75 years, catch cold for 4 to 6 times in last year; * BMI 18.5to 29.9kg/m2; * Able to understand the nature and purpose of the study including potential risks and side effects Exclusion Criteria: * Recent (within 6 months of screening) been vaccinated influenza vaccine, or recent (within 15 days of screening) been vaccinated ther vaccines; * Suffering from rhinitis chronic, laryngitis, labored breathing that similar to flu symptoms. Such as chronic allergic rhinitis, asthma, COPD; * Long-term use of any prescription or OTC medication that inhibit or prevent flu symptoms, including but not limited to, antihistamine, pectoral, high doses of vitamin C; * Recent use (within 3 months of screening) of any prescription or OTC medication that significantly affects immune response, such as antibiotic; * Known allergies to dairy and any substance in the study product; * History of alcohol, drug, or medication abuse * Pregnant or breastfeeding women * Recent daily use (within 3 months of screening) of any probiotics, clabber or yogurt; * Any comorbidity that could, in the opinion of the investigator, preclude the subject's ability to successfully and safely complete the study or that may confound study outcomes