I'm relieved that I do know a little about food safety, especially when it comes to home preserves. I was looking on line to find out about the best state of ripeness to can your pears. Found some great tips about when to pick or buy pears, how to encourage ripening and what they should feel like in your hand when ripe. I found some great tips on the canning process too, complete with suggestions for syrups and spices, I also found; much to my horror; some really great advice on how to risk food poisoning! I am not an expert on this subject, nor am I a bio-chemist or anything of the sort...but PLEASE, please, please people....source out your home preserving information from a trusted publication or government website. To be truly safe, all acid foods (fruit, jams, jellies and pickles) must be processed in a boiling water canner and all non-acid foods (vegetables and meats) need to be processed in a pressure canner...carefully timed according to ingredients, acidity and altitude. Period. If you do wish to preserve food, the best way to start is by getting a booklet, published by a canning company or your local government website that lists recipes, intended jar sizes and the times and methods needed to ensure safe food preservation according to those ingredients.
Here are some great links to websites I trust:
Bernardin, Home Canning Products
Ball Home Canning Products
Food In Jars, A Really Great Blog