answer:There is no quick fix for this kind of research. Unless you are already working in the field of interest, figuring out what the consensus is on a particular topic will require reading many research articles. If you are not affiliated with an institution (college or university), this probably means going to Google Scholar (
http://scholar.google.com/) and typing in key words to do with your question. However, your question is not really a scientific one… it’s a little more complicated. You want to know what kinds of preservatives are needed for specific meats (so that’s a scientific question), and you want to know what preservatives fast food chains are using for those meats (This is more of a news- or business-related question. Scientific papers might not be able to help you here.). Then you want to know why they wouldn’t follow the guidelines, if they don’t (One might assume for monetary reasons, but is there any source that can accurately answer that question?). Where I would start is to type the keywords preservatives “fast food” into Google Scholar. But note that some of the results will be books, which imply opinion, and some will be editorials, and some from periodicals that are not peer reviewed. So have a look not only at the articles, but also at where they were published. After reading a dozen or so papers, you might start to get an idea of what the consensus is… but it’s also important to see what other articles the ones you found are citing. Have a look through their references, and see if you can spot the same ones appearing over and over again. Those are likely to carry more weight. Regarding access, you might not be able to read all of the articles from home without paying – try requesting articles through your library, or doing your research on the guest computers at a local university.