This invention relates to compositions comprising cationic preservatives and anionic hydrocolloids, to methods of preparing them and their application in food microbiological protection. Due to their composition, food products are susceptible to act as a culture medium for microorganisms, and this constitutes a possible risk to human health. Thus, food products require good protection against microbiological contamination. The present invention relates to the interaction between cationic preservatives derived from the condensation of fatty acids and esterified dibasic amino acids and anionic hydrocolloids, such as pectins, xanthan gums, carrageenans, acacia gums or agars. The most preferred cationic preservative is the ethyl ester of the lauramide of arginine monohydrochloride (LAE). As a result of this interaction, some anionic hydrocolloids are able to absorb LAE and precipitate together by the enhancement of their lipophilic properties. These new solid compounds can be isolated by filtration and, surprisingly, retain the microbiological inhibitory activity of LAE. The solid compounds contain approximately stoechiometric amounts of LAE and the anionic hydrocolloid. The preferred solid compound is LAE/xanthan gum. The solid compounds are stable and can be stored under normal conditions of temperature and humidity for long periods of time. The invention relates to the method of preserving food products using the new solid compounds and the food products obtained as a result of the application of the method.