Aim: Hydrosols are hydrodistillation products used in food and cosmetic industries, perfumery, pharmacy and aromatherapy. The ability of preservatives to control previously reported bacterial proliferation and spoilage was evaluated. All tested preservatives were authorized for food and cosmetic application. Methods and Results: Major pathogens of concern for foods and cosmetics were poorly able to grow in rose and orange blossom hydrosols when inoculated and incubated at 30 degrees C. Commercial antimicrobials, such as isothiazolinone, chlorphenesin and paraben solutions, benzyl alcohol and sodium benzoate at pH = 5.0, controlled the growth of Pseudomonas and Burkholderia sp. strains representative of the natural microbiota of both hydrosols for >90 days at 30 degrees C, only at concentrations close to the authorized limits. Concentrations of some of the tested preservatives that controlled growth at 5 degrees C were lower than at 30 degrees C. Conclusion: Pathogenic micro-organisms likely represent a low risk in rose flower and orange blossom hydrosol. However, the oligotrophic character of hydrosols and the antimicrobial properties of their essential oils do not prevent microbiological spoilage by the naturally present microbiota. Significance and Impact of the Study: In the absence of aseptic conditions and microbial inactivation process, only preservatives can stabilize hydrosols for a several-month storage. Several effective preservatives have been identified.