Once opened, Hellman's Mayo typically maintains its best quality for about two months when stored in the refrigerator. It is important to ensure that the container is tightly sealed after each use to prevent contamination and prolong freshness. In general, mayonnaise can last beyond this time frame if stored properly, but its flavor and texture might begin to change. To be certain of its quality, it is advisable to check for any signs of spoilage, such as off smells, changes in color, or any separation that could develop over time. Additionally, it is wise to consult the expiration date on the jar, which can provide further guidance on freshness. Hellman's Mayo packaging may also contain specific storage recommendations. For more details, one could refer to the current web page for accurate and comprehensive information regarding storage and shelf life.