Proper use of campden tablets in a recipe that calls for the staggered addition of a sugar source

[B. Halophilus]

I'm very new to all this, but is my intent to brew an oaked apple maple acerglyn by slightly altering this recipe
http://meadist.com/making-mead/mead-recipes/sparkling-oaked-acerglyn-maple-mead-recipe/
My plan is to brew about five gallons--as per the recipe--but utilize an appropriate amount of campden tablets to preemptively sterilize the must 24 hours before pitching the yeast. However, this recipe calls for adding a quarter gallon of maple syrup before and ten days after pitching. What steps can I take to make sure that the second dose of maple syrup is properly sterile?

I plan on using EC-1118 yeast and after primary fermentation, the ABV should be hovering somewhere around 17-19%. This is when I intend to add about 750mL of apple cider. Should I use a campden tablet to sterilize the cider (which will likely be unpasteurized) or will the alcohol content prevent any bacteria from spreading?

 

[Yooper]

Yes, use campden in the proper dosage (not a whole tablet) to sanitize any fresh cider you add to avoid microbial contamination.

 

[madscientist451]

The OP has two separate questions:

#1 When adding a quart of MAPLE SYRUP, can that be sterilized?

#2 He wants to add 750 ML of APPLE CIDER when the ABV is 17-19%.

My 2 cents: Don't worry about it the 17-19% alcohol should take care of any wild yeast in the cider you are adding. However, you can add sulfites to it if you want to.