29 CFR § 784.147 - Employees “employed in” canning.

All employees whose activities are directly and necessarily a part of the canning of the specified aquatic forms of life are within the exemption provided by section 13(b)(4). Thus, employees engaged in handling the fish or seafood, placing it into the cans, providing steam for cooking it or operating the machinery that seals the cans or the equipment that sterilizes the canned product are engaged in exempt activities. In addition, can loft workers, those engaged in removing and carrying supplies from the stock room for current use in canning operations, and employees whose duty it is to re-form cans, when canning operations are going on, for current use, are engaged in exempt activities. Similarly, the repairing, oiling, or greasing during the active season of canning machinery or equipment currently used in the actual canning operations are exempt activities. The making of repairs in the production room such as to the floor around the canning machinery or equipment would also be deemed exempt activities where the repairs are essential to the continued canning operations or to prevent interruptions in the canning operations. These examples are illustrative but not exhaustive. Employees engaged in other activities which are similarly integrated with and necessary to the actual conduct of the canning operations will also come within the exemption. Employees whose work is not directly and necessarily a part of the canning operations are not exempt. See §§ 784.106, 784.140, and 784.141.