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Microbiological studies on hamburgers

Published online by Cambridge University Press:  25 March 2010

S. K. Tamminga
Affiliation:
Laboratory for Food Microbiology and Hygiene, Agricultural University, Wageningen, The Netherlands
R. R. Beumer
Affiliation:
Laboratory for Food Microbiology and Hygiene, Agricultural University, Wageningen, The Netherlands
E. H. Kampelmacher
Affiliation:
Laboratory for Food Microbiology and Hygiene, Agricultural University, Wageningen, The Netherlands
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Summary

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One hundred and eighty-two raw, 112 pre-cooked and 750 cooked hamburgers composed mainly of beef or beef and pork were subjected to microbiological examination.

Raw hamburgers gave total bacterial counts from 105 to 108 per g, counts of Enterobacteriaceae from 104 to 108 per g, of Escherichia coli from 103 to 105, of group D streptococci from 102 to 104, of Staphylococcus aureus from 3 to 102 and of Clostridium perfringens less than 10 bacteria per g. Of the samples, 32 % contained salmonellas; the highest most probable number was 102 per g but most estimates were below 1 per g. Corresponding figures for the pre-cooked samples were 2–3 log cycles lower, and only one sample contained salmonella. Yersinia enterocolitica was not isolated from any raw or pre-cooked sample.

Three hundred and ninety-five of the cooked hamburgers were prepared by grilling raw hamburgers for between 2 and 5·5 min. These gave total bacterial counts from 105 to 107 per g, and counts of Enterobacteriaceae from 102 to 105 per g. Of the samples, 9·4 % contained salmonellas, always in numbers below 1 per g. The remaining 355 cooked hamburgers were prepared from samples pre-cooked for 10 min at 80 °C. Some were grilled and some fat fried. The total bacterial counts were from 103 to 105 per g, and counts of Enterobacteriaceae below 102 perg. Salmonellae, again in small numbers only, were recovered from 3·5 % of samples.

When hamburgers were artificially contaminated with Salmonella typhimurium it took 5·5 min on a commercial grill, 2·25 min frying in a frying pan and 1·75 min on a household grill to reliably reduce the salmonella count one hundredfold. This means that at many vending places hamburgers are often cooked for too short a time.

D-values were determined for S. typhimurium in hamburger meat at 50, 55, 60, 65 and 70 °C, these values were 7·1, 5·1, 1·2, 0·9 and 0·6 min respectively. It can be concluded that the heating action in the centre of the hamburgers will take place more slowly than in the hamburger as a whole, and that the time between cooking and consumption is very important in reducing the microbial load to acceptable levels.

Pre-cooking (10 min at 80 °C in a water bath) gives a reduction in the numbers of salmonella of about 4 × 103, after which cooking gives a further reduction as mentioned above.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1982

References

Baird-Parker, A. C. (1962). An improved diagnostic and selective medium for isolating coagulese positive staphylococci. Journal of Applied Bacteriology 25, 1219.CrossRefGoogle Scholar
Baird-Parker, A. C., Boothroyd, M. & Jones, E. (1970). The effect of water activity on the heat resistance of heat sensitive and heat resistant strains of Salmonella. Journal of Applied Bacteriology 33, 515522.CrossRefGoogle Scholar
Chambers, J. V., Breckbill, D. O. & Hill, D. A. (1976). A microbiological survey of ground beef in Ohio. Journal of Milk and Food Technology 39, 530535.CrossRefGoogle Scholar
Corry, J. E. L. (1974). The effect of sugars and polyols on the heat resistance of salmonella. Journal of Applied Bacteriology 37, 3143.CrossRefGoogle Scholar
Dempster, J. F. & Cody, O. H. (1978). Bacteriological and chemical status of minced beef. Irish Journal of Food Technology 2, 111.Google Scholar
Digiacinto, J. V. & Frazer, W. C. (1966). Effect of coliform and Proteus bacteria on growth of Staphylococcus aureus. Applied Microbiology 14, 124129.CrossRefGoogle ScholarPubMed
Duitschaever, C. L., Arnott, D. R. & Bullock, D. H. (1973). Bacteriological quality of raw, refrigerated ground beef. Journal of Milk and Food Technology 36, 375377.CrossRefGoogle Scholar
Duitschaever, C. L., Bullock, D. H. & Arnott, D. R. (1977). Bacteriological evaluation of retail ground beef, frozen beef patties and cooked hamburger. Journal of Food Protection 40, 378381.CrossRefGoogle ScholarPubMed
Edel, W., Leusden, F. M. van & Kampelmacher, E. H. (1978). Salmonella in gehakt afkomstig van 10 vleeskeuringsdiensten in Nederland. Tijdschrift voor Diergeneeskunde 103, 220228.Google Scholar
Emswiler, B. S., Pierson, C. J., Kotula, A. W. & Cross, H. R. (1979). Microbiological evaluation of pre-cooked beef patties containing soya protein. Journal of Food Science 44, 154157.CrossRefGoogle Scholar
Fontaine, R. E., Arnon, S., Martin, W. T., Vernon, T. M. Jr, Gangarosa, E. J., Farmer, J. J. III, Moran, A. B., Silliker, J. H. & Decker, D. L. (1978). Raw hamburger: An interstate common source of human salmonellosis. American Journal of Epidemiology 107, 3645.CrossRefGoogle ScholarPubMed
Foster, J. F., Fowler, J. L. & Ladiges, W. C. (1977). A bacteriological survey of raw ground beef. Journal of Food Protection 40, 790794.CrossRefGoogle ScholarPubMed
Gibson, B. (1973). The effect of high sugar concentration on the heat resistance of vegetative micro-organisms. Journal of Applied Bacteriology 36, 365376.CrossRefGoogle ScholarPubMed
Giolitti, G. & Cantoni, C. (1966). A medium for the isolation of staphylococci from foodstuffs. Journal of Applied Bacteriology 29, 395398.CrossRefGoogle ScholarPubMed
Goepfert, J. M. (1976). The aerobic plate count, coliform and Escherichia coli content of raw ground beef at the retail level. Journal of Milk and Food Technology 39, 175178.CrossRefGoogle Scholar
Goepfert, J. M. (1977). Aerobic plate count and Escherichia coli determination on frozen ground-beef patties. Applied and Environmental Microbiology 34, 458460.CrossRefGoogle ScholarPubMed
Goepfert, J. M., Iskander, I. K. & Amundson, C. H. (1970). Relation of the heat-resistance of salmonellae to the water activity of the environment. Applied Microbiology 19, 429433.CrossRefGoogle Scholar
Harmon, S. M. & Kautter, D. A. (1978). Media for confirming Clostridium perfringens from food and feces. Journal of Food Protection 41, 626630.CrossRefGoogle ScholarPubMed
Hauschild, A. H. & Hilsheimer, R. (1974). Evaluation and modifications of media for enumeration of Clostridium perfringens. Applied Microbiology 27, 7882.CrossRefGoogle ScholarPubMed
I.S.O. 3565 (1975). International Standard ISO 3565. Meat and Meat Products – Detection of Salmonella (Reference Method), 1st ed. 1975–09–01. Geneva: International Organization for Standardization.Google Scholar
I.S.O. 2293 (1976). International Standard ISO 2293. Meat and Meat Products – Aerobic count at 30 C (Reference Method), 1st ed.Geneva: International Organization for Standardization.Google Scholar
I.S.O. 4833 (1978 a). International Standard ISO 4833. Microbiology – General Guidance for Enumeration of Micro-organisms – Colony Count Technique at 30 C, 1st ed. 1978–02–01, Geneva: International Organization for Standardization.Google Scholar
I.S.O. 4832 (1978 b). International Standard ISO 4832. Microbiology – General Guidance for Enumeration of Coliforms – Colony Count Technique at 30 C, 1st ed. 1978–02–01. Geneva: International Organization for Standardization.Google Scholar
I.S.O. 4831 (1978 c). International Standard ISO 4831. Microbiology – General Guidance for the Enumeration of Coliforms – Most probable Number Technique at 30 C, 1st ed. 1978–08–15. Geneva: International Organization for Standardization.Google Scholar
I.S.O 5552 (1979). International Standard ISO 5552. Meat and Meat Products – Detection and Enumeration of Enterobacteriaceae (Reference Methods), 1st ed. 1979–04–01. Geneva: International Organization for Standardization.Google Scholar
Juhlin, I. & Ericson, C. (1961). A new medium for the bacteriologic examination of stools (LSU-agar). Acta Pathologica et Microbiologica Scandinavica 52, 185200.CrossRefGoogle ScholarPubMed
McCoy, D. W. & Faber, J. E. (1966). Influence of food micro-organisms on staphylococcal growth and enterotoxin production in meat. Applied Microbiology 14, 372377.CrossRefGoogle Scholar
McKenzie, E. F. W., Taylor, E. W. & Gilbert, W. E. (1948). Recent experiences in the rapid identification of Bacterium coli type I. Journal of General Microbiology 2, 197204.CrossRefGoogle Scholar
Miskimin, D. K., Berkowitz, K. A., Solberg, M., Riha, W. E. Jr, Franke, W. C., Buchanan, R. L. & O'leary, V. (1976). Relationship between indicator organism and specific pathogen in potentially hazardous foods. Journal of Food Science 41, 10011006.CrossRefGoogle Scholar
Mossel, D. A. A., Eeldekrink, I., Vor, H. de & Keizer, E. D. (1976). Use of agar immersion, plating and contact (AIPC) slides for the bacteriological monitoring of food. meals and the food environment. Laboratory Practice 25, 393395.Google ScholarPubMed
Mueller, D. C. (1975). Microbiological safety and palatability of selected vended burgers. Journal of Milk and Food Technology 38, 135137.CrossRefGoogle Scholar
Newton, K. G. (1979). Value of coliform tests for assessing meat quality. Journal of Applied Bacteriology 47, 313–307.CrossRefGoogle ScholarPubMed
Oosterom, J. (1979). Isolation and epidemiological significance of Yersinia enterocolotica Antonie van Leeuuenhoek. Journal of Microbiology 45, 630633.Google Scholar
Pivnick, H., Erdman, I. E., Collins-Thompson, D., Roberts, G., Johnston, M. A., Conley, D. R., Lachapelle, G., Purvis, U. T., Foster, R. & Milling, M. (1976). Proposed microbiological standards for ground beef based on a Canadian survey. Journal of Milk and Food Technology 39, 408412.CrossRefGoogle Scholar
Schothorst, M. van (1971). Hygiënische aspecten van de vleeswarenbereiding. Vordingsmid delentechnologie 2 (4). 68.Google Scholar
Surkiewicz, B. K., Harris, M. E., Elliott, R. P., Macaluso, J. F., Strand, M. M. (1975). Bacteriological survey of raw beef patties produced at establishments under federal inspection. Applied Microbiology 29, 331334.CrossRefGoogle ScholarPubMed
Wauters, G. (1973). Contributions to Microbiology and Immunology, vol. 2 (ed. Grümbach, A.). pp. 6870. Basel: Karger.Google Scholar
Westhoff, D. & Feldstein, F. (1976). Bacteriological analysis of ground beef. Journal of Milk and Food Technology 39, 401404.CrossRefGoogle Scholar
Willis, A. T. & Hobbs, G. (1959). Some new media for the isolation and identification of Clostridia. Journal of l'athology and Bacteriology 77, 511.CrossRefGoogle ScholarPubMed