An increased AST level is usually a sign of liver disease. Liver disease is even more likely when the levels of substances checked by other liver blood tests have also increased. An increased AST level may be due to any of the following:
In order to keep itself fresh, the lettuce gives off carbon dioxide, causing a slight odour. This carbon dioxide is not harmful and the odour should disappear quickly once the salad package is opened.
There are many different types of preservatives that it can be quite confusing. If you are preserving a jar product (with a largish headspace), including phenoxyethanol in your preservative mix is a very good idea to have in there as it will keep the headspace clean.