The immunomodulatory properties of probiotic microorganisms beyond their viability (ghost probiotics: proposal of paraprobiotic concept)

In the light of the FAO/WHO definition of probiotics, indicating that the word ‘probiotic’ should be restricted to products that contain live microorganisms, and considering the scientific evidence indicating that inactivated microbes can positively affect human health, the new term ‘paraprobiotic' is proposed to indicate the use of inactivated microbial cells or cell fractions to confer a health benefit to the consumer.