A substantially transparent package or preform made of a polymer composition including an aliphatic polyketone as an oxygen scavenger having the formula ##STR1## where n is the number of repeating units and R is hydrogen, an organic side chain, or a silicon side chain. The aliphatic polyketone may be advantageously combined with other thermoplastic polymers to provide the desired injection molding and stretch blow molding characteristics for making substantially amorphous injection molded preforms and substantially transparent biaxially oriented polyester containers. A multilayer container package may be provided having a core layer of the oxygen scavenging composition, and inner and outer layers of polyethylene terephthalate (PET). The container may further include layers of a high-oxygen barrier polymer such as ethylene vinyl alcohol (EVOH). When filled with a liquid product including water, the water vapor from the product may permeate the inner and core layers to facilitate removal and consumption of entrapped oxygen by the core scavenging layer. The aliphatic polyketone provides a highly reactive oxygen scavenger which is made from low-cost monomers and which remains colorless during processing.