Before you clear out the fridge door, pick up the open ranch dressing and the mustard. Each bottle has a printed date, but the two may have different instructions once you break the seal. Start with when you opened the bottle and how you stored it.
Read the line about storage after opening
Look near the ingredients or the cap for instructions such as “refrigerate after opening” or “use within” a set period. The FoodKeeper guide lists storage advice by product if the label gives no window. Search for the kind of sauce you have. A shelf-stable jar and a tub sold chilled can have different directions.
A “best if used by” date describes peak quality, according to the FDA’s explanation of food date labels. Use the printed date with the storage directions and the time since opening. If a perishable dressing needs refrigeration and you can’t account for how long it sat warm, skip the taste test and discard it.
Give creamy dressings their own check
During a power outage, check the FoodSafety.gov refrigerator chart. Under the conditions listed there, mustard and ketchup can be kept while opened creamy dressing should be discarded. Opened mayonnaise has its own time and temperature cutoff in the chart. Use the row for the product you have.
Check the neck and lid of jam jars. If you see mold on the jam, discard the jar. The USDA’s mold guide advises against scooping off the surface and using what’s underneath.
Write the opening date on the next bottle
Keep a marker near the fridge and date the cap when you open a jar. Before buying another bottle, check what you already have and plan a meal that uses it. If you use a sauce once a month, a smaller bottle may save more than a bulk deal.
Use the same label check when sorting foods that may need a spot outside the pantry.