Rationale: Infections are an important worldwide cause of death, both in elderly and young children. Therefore, support of immunity could help to reduce the incidence of infections. To screen the potential of specific foods or food ingredients to support immunity, oral vaccination can serve as a model. In this study, oral cholera vaccination will be applied in human adult volunteers, and used as a model to study the support of the immune response by raw milk.

Objective: To investigate whether raw milk is able to enhance the immune response as induced by oral cholera vaccination.

Study design: The study is designed as a single-blind randomized controlled trial of 4 weeks.

Study population: Healthy subjects of 18-50 years of age.

Intervention: Raw milk, obtained from farms that comply to the high quality requirements for production of raw milk, and that has been screened according to the safety criteria for raw milk.

Inclusion Criteria:

• Age 18-50 yr
• Signed informed consent
• Availability of internet connection
• Male or female
• Willing to stop blood donation at the blood bank during the study period

Exclusion Criteria:

• Currently participating in another clinical trial
• Previous Cholera, Salmonella, or E. coli vaccination
• Tonsillectomy
• Acute gastroenteritis in the past 2 months
• Use of antibiotics in the past 2 months
• Hypersensitivity to the vaccine, to formaldehyde or to any of the excipients (sodium salts)
• Pregnancy or lactating (pregnancy test will be performed on the vaccination days)
• Not willing to drink raw milk
• Allergic to milk or lactose-intolerant
• Disease of GI tract, liver, gall bladder, kidneys, thyroid gland
• Immune-compromised
• Use of immunosuppressive drugs
• Drug abuse, and not willing/able to stop this during the study
• Excessive alcohol usage (men: >4 consumptions/day or >20 consumptions/week; women: >3 consumptions/day or >15 consumptions/week)