I cooked turkey breakfast sausages in a 350 F convection oven and one exploded. The stuff that came out looked a little foamy and the juices before it was cooked looked a tiny bit foamy. This may be completely normal but just want to be sure if it sounds safe to eat. The sausages were packaged five days ago and expire in two days. They didn't smell bad or anything. Thanks!
That foam is perfectly natural.
The foam is the result of meats natural protein composition. If you've ever poached eggs, or boiled lobster, or cooked a stock, you'll know that the water can become a little scummy. If you leave the pot on, that scum makes a white-ish or grey-ish foam that forms lovely looking rafts. That foam is made of water soluble protein.
In your case, you have wet sausage meat in a case. A small amount of that meat's proteins, mostly sarcoplasm and myoglobin, are going to escape from their cells and into the meat juice.
When the sausage case breaks, that juice, a mix of water and protein, is escaping into a hot oven, and the proteins are going to spontaneously denature, forming a foam much like scrambled eggs.
If anything, you should be happy- water soluble albumin foam is a sign that the sausage is full of proteins, and is definitely made of meat, and not, say, recycled chipboard.
Enjoy the sausages!
I suspect the foam is because turkey breakfast sausages have listed as their main ingredients 'turkey, water and then potato extract - the amount of protein per 2 sausage serving appears to be only 13g, along with 7 g of fat. Calcium and salt are added, along with other nameless 'flavourings' and probably preservatives. If a sausage bursts, it's likely to look foamy when heated because of the potato starch and water combination but certain preservatives will contribute to a white or whitish foam when the product is heated (commonly seen with bacon); indicates a wet cure, or a product with a high proportion of water and some salt - it's likely the same with the sausages. Figures taken from Shady Brook Farms Turkey Breakfast Sausages - the packet also carries instructions about being careful regarding not piercing the skins, presumably because of what happens when you do - foamy stuff.