CONTRACT RESEARCH PROJECT REPORT QUARTERMASTER FOOD AND CONTAINER INSTITUTE FOR THE ARMED FORCES, CHICAGO Hq, vQ Research and Development Command, QM Research and Development Center, Natick, Mass. Univers:ity of Michigan Engineering Research Institute Ann Arbor, Michigan Official Investigator: Lloyd. L. o Impe,Collaborators: J. T Graikoskl Nancy J. Wil.liams: Prdiect No. 7-84-01-002 Contra.crt:4 A-19-129-qm-388 Pi]:;.. No...Sk 510 e-brt...No.' l^(Progress) Pegri6d.': 7 June 1955-.7'August 1955 ITi.ti.ato.nL ate: 7 June 1955 Title of Contract: Combined Use of:PHeat::nd Radiation Treatment foi' S'terilization of Foods SUMMARY Studies have been initiated to determine the combined effects of irradiation and heat on canned meat. For this purpose a steam autoclave has been modified to accommodate the 0. F. Ecklund thermocouple apparatus and to permit close control of time-temperature relationships within No. 1 picnic cans of meat during autoclaving. At present, runs are being made that are designed to determine the FO, or effective heating time at 250~F, required to sterilize No. 1 picnic cans of ground beef after irradiation at various levels with gamma rays from cobalt-60. The cans are first packed with autoclaved ground beef and are then sterilized by further heating with 17 psig steam for 1 hour. Following this, Clostridium botulinum 2.13-B spores are injected into the meat. The cans are then immediately sealed with a commercialtype closing machine, plunged into water at 20'C for 10 minutes, marked, THIS IS NOT A FINAL REPORT. CONCLUSIONS STATED ARE SUBJECT TO CHANGE ON THE BASIS OF ADDITIONAL EVIDENCE. THIS INFORMATION IS NOT TO BE REPRINTED OR PUBLISHED WITHOUT WRITTEN PERMISSION FROM HQ, QM RESEARCH AND DEVELOPMENT COMMAND, NATICK, MASSACHUSETTS.

and further chilled in ice water to about 4~C. They are next irradiated at various levels, autoclaved to develop the desired Fo values, cooled quickly to 37~C and then incubated at this temperature. Development of gas in the cans is observed, and representative cans are checked for the presence of botulinus toxin by animal inoculation tests. Although four runs have been made, the incubation of cans has not progressed sufficiently for reporting at this time. Studies on the effect of chemicals in the medium on effect of gamma rays for C. botulinum spores are continuing. the simultaneous application of heat and irradiation are also Detailed data will be presented in Progress Report No. 2. the lethal Studies of in progress.