Effect of Pre-Processing Steps, Nitrite and Irradiation Combination Preservation of a Ready-to-Eat Spinach Relish and Sorghum Porridge Meal
- 1 Central Veterinary Laboratory, Ministry of Agriculture Water and Forestry, Windhoek, Namibia
Abstract
The effects of pre-processing steps (washing, blanching and cooking) and combination preservation of irradiation (10 kGy) and nitrite (0, 50, 100, 150 and 200 mg·kg –1 ) on the survival of Clostridium sporogenes spores in a ready-to-eat (RTE) spinach relish and sorghum porridge meal were investigated. Chlorine wash (250 mg –1 ) reduced the C. sporogenes counts in spinach by 1.6 log cycles. Blanching following the chlorine wash caused no significant decrease in the spore counts in spinach. On the other hand, cooking significantly reduced the counts in the porridge by about 1.7 log cycles. In both components of the meal, there was a significant decrease in the Clostridia counts with increased sodium nitrite levels. However, the counts increased in the sorghum porridge component after 12 d of storage at 10℃. Cooking alone significantly reduced the final nitrite levels in both components of the meal. In both components of the meal, nitrite in combination with irradiation reduced the C. sporogenes counts to less than 10 cfu/g. A safe RTE spinach relish and sorghum porridge meal could be expected when a pre-processing, followed by a combination treatment of at least 50 mg·kg –1 sodium nitrite and a target dose of 10 kGy is applied.
- A. O. Obilana, “Modified Atmosphere Packaging and Irradiation Preservation of Sorghum Porridge and Spinach Relish Meal,” M.Sc. Dissertation, University of Pretoria, Pretoria, 1998.
- D. J. Olson, “Irradiation of Food: A Publication of the Institute of Food Techologist’s Expert Panel on Food Safety and Nutrition,” Food Technology, Vol. 52 No. 1, 1998, pp. 56-62.
- J. E. Prejean, “Food Irradiation: Why Aren’t We Using It?” J.D. Dessertation,. Havard Law School, Harvard, 2001.
- J. S. Smith and S. Pillai, “Irradiation and Food Safety,” Food Safety, Vol. 58 No. 11, 2004, pp. 48-55.
- L. N. Christiansen, “Factors Influencing Botulinal Inhibition by Nitrite,” Food Technology, Vol. 10, 1980, pp. 237-239.
- K. G. Duodu, A. Minnaar and J. R. N. Taylor, “Effect of Cooking and Irradiation on the Labile Vitamins and Antinutrient Content of a Traditional African Sorghum Porridge and Spinach Relish,” Food Chemistry, Vol. 66, No. 1, 1999, pp. 21-27. doi:10.1016/S0308-8146(98)00070-3
- Association of Official Analytical Chemists, “Official Methods of Analysis of the Association of Official Analytical Chemists,” Method 39.1.21., Washington DC, 1995.
- A. Anellis, E. Shattuck, D. B. Rowley, E. W. Ross, D. N. Whaley and V. R. Dowell, “Low-Temperature Irradiation of Beef and Methods for Evaluation of a Radappertization Process,” Applied Microbiology, Vol. 30, No. 5, 1975, pp. 811-820.
- “General Standard for Irradiated Foods Codex Standards 106-1983,” 2003. http://www.codexalimentarius.net/download/standards/16/CXS_106e.pdf
- W. B. Hugo and A. D. Russell, “Type of Antimicrobial Agents,” In: A. D. Russell, W. B. Hugo and G. A. J. Ayliffe, Eds., Principles and Practice of Disinfection, Preservation and Sterilization, Blackwell Scientific Publication, Oxford, 1982, p. 8.
- A. Anderson, U. Ronner and P. Granum, “What Problems Does the Food Industry Have with Spore-Forming Pathogens, Bacillus cereus and Clostridium perfrigens?” International Journal of Food Microbiology, Vol. 28, No. 2, 1995, pp. 145-155.
- F. M. Driessen, “Importance of Bacillus cereus in Fermeted Milks and Processed Non-Fermented Dairy Foods,” Bulletin of the International Dairy Federation, Vol. 287, 1992, pp. 11-15.
- M. W. Peck, B. M. Lund, D. A. Fairbairn, A. S. Kaspersson and P. C. Underland, “Effect of Heat Treatment on Survival of and Growth from Spores of No-Proteolytic Clostridium botulinum at Refrigeration Temperatures,” Applied and Environmental Microbiology, Vol. 61, No. 5, 1995, pp. 1780-1785.