Guacamole recipes contain raw produce, such as avocados, tomatoes and hot peppers, as the base. Left unrefrigerated, these ingredients are susceptible to dangerous bacteria growth. An overgrowth of this bacteria is responsible for foodborne illness breakouts associated with guacamole. Norovirus, Salmonella and E. coli are the most common illnesses linked to bacteria-laced guacamole, each of which have the potential of causing serious health complications. Refrigerating the guacamole after serving reduces these risks.

Ideal refrigeration temperatures for guacamole are 40 degrees Fahrenheit and below. Outside of these temperatures, guacamole should only remain unrefrigerated for up to two hours. Refrigeration slows this growth. After two hours, bacteria levels multiply rapidly rendering the guacamole unsafe to eat. Guacamole sitting out in temperatures of 90 degrees F and above is only safe to eat for one hour. Guacamole that sits out longer than recommended should be thrown away and not placed back in the refrigerator.

Stored inside the refrigerator, guacamole keeps for approximately three to four days before going bad. Refrigeration does not kill bacteria, it only slows its growth. After a four-day storage period, enough bacteria has developed to render the guacamole unsafe to eat. Once the guacamole reaches this stage it will need to be discarded. The ingredients contained in guacamole do not freeze well, so freezing is not a recommended option for long-term storage.

Oxidation causes guacamole to turn brown after being exposed to air. Although it may look unappetizing, the browning is not harmful and only affects the top layer. Remove the brown areas with a spoon before serving. To prevent browning, store the guacamole in an airtight container, covering the guacamole with a layer of clear plastic wrap before attaching the lid and popping it in the refrigerator. Adding lemon juice to your guacamole recipes also staves off browning.