Place the sweetened condensed milk and the pineapple chunks in a blender and puree until very smooth. Pass the mixture through a fine mesh strainer, pressing firmly. Discard the remaining pulp. Stir the milk and lemon juice into the pineapple puree and chill for 30 minutes.
Using your ice cream maker, freeze the sherbet following the manufacturer’s directions. Place it in an airtight container and cover. Freeze at least one hour before serving.
Yield: 1 quart