Possible means of blood component bacterial contamination involve the blood donor, the collection process, the collection pack, and blood processing. Most bacteremic individuals are symptomatic and would not be accepted as donors. In the United States, a person cannot donate if his or her temperature is above 37°C. Sometimes a donor may be in an incubation period or in the recovery phase of bacterial infection and this may lead to contamination of their blood products. Most of the organisms isolated from platelet concentrates are normal skin flora which entered the bag during venipuncture when skin is not disinfected properly. Some organisms may even remain viable on the skin after disinfection. The donor's skin may also contain unusual pathogens. Clostridium perfringens was linked to a donor who had recently changed a child's diaper. Blood bags can be contaminated on the outer surfaces. The bacteria can enter the unit at the time of blood donation either through suction into the needle or contamination of the phlebotomist's hands and then on the donor's skin. Contamination during blood processing can occur from thawing frozen products in a contaminated water bath. Bacteria can enter the unit through microcracks in the bags or through pooling.