Thanks to you all for your responses. Much of my issue was brought onto myself by my own self-doubt. My use of mayonnaise is only occasionally. Fairly recently, when I re-opened a jar of Hellmann's, I thought it was a bit thin and it had a faint vinegary odor that I had not noticed before. Thinking that I had been careless with it, I discarded that jar and opened a new jar. The new jar had that same thin consistency and faint vinegary odor. It was only after a couple batches of potato salad that tasted a bit off to me that I dared to challenge the integrity of the iconic mayonnaise.