Guidelines and Precautions. The jury is still out on melatoninâs effects on blood pressure. If you have high or low blood pressure, or take medications to control your blood pressure, it is best to avoid the supplement unless advised otherwise by your doctor.uidelines and Precautions. The jury is still out on melatoninâs effects on blood pressure. If you have high or low blood pressure, or take medications to control your blood pressure, it is best to avoid the supplement unless advised otherwise by your doctor.
1 This can cause the can to bulge or rust.  Use canned tuna by the expiration date on the can. If the can doesn't have a best by date, mark it with the date of purchase and use the tuna within 12 to 24 months of purchase.
Canned foods have a long shelf life, but that shouldnât mean that you keep them for several years before using them. High-acid canned foods such as juices, tomatoes, fruits and pickles will store well for 12 to 18 months. Whereas low-acid canned foods such as meat products and vegetables will store well for 2-4 years.However, there may be some changes in quality, such as a change in colour and texture.