Modern food production is in constant flux in ways that effect Kashrus – some for the better and some for the worse. A number of developments which have raised Kashrus concerns follow:
Most natural sweetener used in juices and other products is white grape juice (with all of the attendant kashrus concerns). The Kashrus agencies make sure that only Kosher grape juice is used in products which they certify.
When companies produce powdered milk, they recycle the chemically pure hot water which is produced. Not only is the water a valued commodity but the fact that it is hot makes it more valuable. Even though this water is chemically 100% pure and not a concern regarding allergies, it is clearly a component of milk. Even for people who do use standard milk it is a meat/milk concern.
The same issue of a hot water byproduct applies when manufacturing starch. The obvious issue here is “Chometz” on Pesach.
Many canning companies are using their canning equipment for non-kosher (meat/fish) products. For this reason, the Kashrus agencies recommend using only kosher certified canned goods. This is not a concern in regard to frozen vegetables that contain only kosher ingredients.