Method of obtaining acceptable configuration of a plastic container after thermal food sterilization process

A plastic container for packaging food, which container is thermally sterilizable to render shelf stable food packed and sealed in the container which comprises:

• a sidewall and a bottom wall, the bottom wall being adapted, when the container is filled with food and sealed to deform and accommodate increases in internal pressure and increases in volume of the container without bursting during thermal sterilization,
• said bottom wall having portions of less stress resistance relative to other portions of the bottom wall and relative to the sidewall,
• and having approximately the same surface area as would a spherical cap whose volume is the sum of the undeformed volume of the bottom wall plus the desired volume increase, the volume "V" of said cap being determinable by the following equation:
• V=1/6.pi.h(3a.sup.2 +h.sup.2)
• where "h" is the height of the dome of the spherical cap, and "a" is the radius of the container at the intersection of the side wall and the bottom wall, wherein the surface area "S.sub.2 " of the cap may be calculated by the following equation:
• S.sub.2 =.pi.(a.sup.2 +h.sup.2)4/3
• wherein the ratio of the "h" dimension to the "a" dimension is expressed as:
• k=h.sub.a or h=ka, where k=about 0.47.

A plastic container for packaging food, which container is thermally sterilizable to render shelf stable food packed and sealed in the container which comprises:

• a sidewall and a bottom wall, the bottom wall being adapted, when the container is filled with food and sealed to deform and accommodate increases in internal pressure and increases in volume of the container without bursting during thermal sterilization,
• said bottom wall having approximately the same surface area as would a spherical cap whose volume is the sum of the undeformed volume of the bottom wall plus the desired volume increase, the volume "V" of said cap being determinable by the following equation:
• V=1/6.pi.h(3a.sup.2 +h.sup.2)
• where "h" is the height of the dome of the spherical cap, and "a" is the radius of the container at the intersection of the side wall and the bottom wall, wherein the surface area "S.sub.2" of the cap may be calculated by the following equation:
• S.sub.2 =.pi.(a.sup.2 +h.sup.2)4/3
• wherein the ratio of the "h" dimension to the "a" dimension is expressed as:
• k=h/.sub.a or h=ka, where k=about 0.47.

A plastic container for packaging food, which container is thermally sterilizable to render shelf stable food packed and sealed in the container which comprises:

• a sidewall and a bottom wall, the bottom wall being adapted, when the container is filled with food and sealed to deform and accommodate increases in internal pressure and increases in volume of the container without bursting during thermal sterilization,
• said bottom wall having portions of less stress resistance relative to other portions of the bottom wall and relative to the sidewall,
• and having approximately the same surface area as would a spherical cap whose volume is the sum of the undeformed volume of the bottom wall plus the desired volume increase, the volume "V" of said cap being determinable by the following equation:
• V=1/6.pi.h(3a.sup.2 +h.sup.2)
• where "h" is the height of the dome of the spherical cap, and "a" is the radius of the container at the intersection of the side wall and the bottom wall, wherein the surface area "S.sub.2 " of the cap may be calculated by the following equation:
• S.sub.2 =.pi.(a.sup.2 +h.sup.2)4/3
• wherein the desired volume increase is about 5% of total volume of the container.