Packets of mayonnaise are generally designed to be kept at room temperature, unless the label reads "keep refrigerated". The shelf life of the packets is only a couple months. Refrigeration may help extend the shelf life.
For sure! You can get food poisoning from eating mayonnaise that has been left out of the fridge too long, and it spoils quicker with increased temperature.
It can, but not for long.
A turkey sandwich with mayonnaise should be eaten within three hours if not kept cool. Mayonnaise has a tendency to spoil rather quickly at room temperature.
Sealed cream cheese can be left out at room temperature for up to 2 hours before it spoils. After that, it should be refrigerated to maintain freshness and prevent bacteria growth.
not too long
A fondant-covered cake filled with cream cheese filling should generally not be left at room temperature for more than 2 to 4 hours. Cream cheese is perishable and can spoil if left out too long, especially in warm conditions. To ensure safety and maintain quality, it's best to refrigerate the cake if it will be out for an extended period. Always check for any signs of spoilage before serving.
Mayonnaise Spoilage Myths - Mayonnaise Safety http://homecooking.about.com/od/howtocookwithcondiments/a/mayospoilage.htm
For up to 30 minutes.
That depends on the freshness of the cream and the temperature at which it is stored. It will smell (and taste) sour when it spoils.
They don't make cheese with mayonnaise
Ice cream at room temperature melts.
Yes. It should be fine as long as it has not been left out in extreme temperatures, uncovered.