An evaluation of milk enriched with royal jelly

In an attempt to extend the range of "novelty dairy foods", a study of enrichment of milk with royal jelly was initiated. It was found that royal jelly inhibits the development of mesophilic and thermophilic dairy starters in milk, as well as several single-strain Gram-positive and Gram-negative bacteria, in growth media. Simulated heat pasteurization or treatment with calf rennet, before testing, did not abolish the antibacterial activity of royal jelly. In principle, an additive such as royal jelly with a wide range of antimicrobial effects would preclude the conversion of milk to fermented products. However, a sensory evaluation of milk samples enriched with increasing concentrations of royal jelly indicated that below 0.5% the additive's presence was not detected and the delay in culture growth can be technologically accomodated, but it should be taken in account in further research and development work.