Irradiation of edible food animal offal

Edible offal is economically and nutritionally of considerable significance to traditional consumers. Most offal is sold as rough washed offal (RWO) and is highly perishable and since consumers and retailers of offal rarely possess regrigerators, shelf life is limited. This food harbours potentially pathogenic or toxigenic micro-organisms. Methods are therefore required to improve its microbiological state without adding to the cost or significantly altering the natural appearance of the product. Counts of total aerobic and anearobic mesophilic bacteria decreased by more than 90% after gamma-irradiation treatment at 1 to 2 kGy but species of certain genera notably Bacillus, Micrococcus, Streptococcus, Staphylococcus and Clostridium survived up to 6 kGy. S. aureus, S. dublin and C. perfringens could not be recovered from inoculated minced RWO after 6 kGy irradiation. It appears that the keeping quality of RWO could be extended by a factor of 2 to 3 by radurisation. The advantange of irradiation was generally more marked in material stored at room temperature at 4 degrees Celsius. Heating of RWO to 80 degrees Celsius prior to irradiation at 4 kGy gave better results than irradiation at 6 kGy. A limited organoleptic evaluation failed to yield conclusive results. Although irradiation of offal holds certain promise, further work is required. The economics of the process have not yet been investigated