612 Modern Food Microbiology
The view in Germany is that zero tolerance is not only unrealistic but unnecessary, and foods are
placed in four risk levels somewhat along the lines of Canada. Products that contain >10
4 /g are subject
to an automatic recall.
Australia requires the absence of L. monocytogenes in 5 × 25-g samples for many cheeses. France requires no L. monocytogenes in 25-g samples of foods for at-risk individuals. The French position seems
to be that it is unrealistic to expect no L. monocytogenes in raw foods. It has been noted that the presence
of this organism in food processing environments is inevitable, especially those for finished products;
and that while the risks of final product contamination can be reduced, they cannot be eliminated.
125
The International Commission on Microbiological Specification for Foods (ICMSF) has concluded
that if this organism does not exceed 100/g of food at point of consumption, the food is considered
acceptable for individuals who are not at risk (see FSO in Chapter 20). The ICMSF endorses the use
of HACCP (see Chapter 21), and places L. monocytogenes in plan stringency cases nos. 10, 11, and
12 (see Table 21–4). The two-class sampling plan for case 10 is n = 5, c = 0; for cases 11, n = 10,
c = 0; and for case 12, n = 20, c = 0. For the years 1994–1998, L . monocytogenes was responsible
for 61% of the 1,328 food product recalls in the United States followed by 11% for salmonellae.
132
However, it is not correct to assume that all recalled foods would have caused listeriosis cases had
they been sold. As noted above, not all strains of this organisms cause human illness; and RTE meat
and poultry products are not handled the same way by different consumers.
REFERENCES
1. Ade, N., S. Steinmeyer, M.J. Loessner, H. Hof, and J. Kreft (Technical University of Munich, Weihenstephan, Freising,
Germany). 1991. Personal communication.
2. Anton, W. 1934. Kritisch-experimenteller Beitrag zur Biologie des Bacterium monocytogenes. Mit basonderer Beruecksichtigung seiner Beziehung zur infektiosen Mononucleose des Menschen. Zbl. Bakteriol. Abt. I. Orig. 131:89–103.
3. Audurier, A., and C. Martin. 1989. Phage typing of Listeria monocytogenes. Int. J. Food Microbiol. 8:251–257.
4. Baldridge, J.R., R.A. Barry, and D.J. Hinrichs. 1990. Expression of systemic protection and delayed-type hypersensitivity
to Listeria monocytogenes is mediated by different T-cell subsets. Infect. Immun. 58:654–658.
5. Bartlett, F.M., and A.E. Hawke. 1995. Heat resistance of Listeria monocytogenes Scott A and HAL 957E1 in various
liquid egg products. J. Food Protect. 58:1211–1214.
6. Beuchat, L.R., and R.E. Brackett. 1989. Observations on survival and thermal inactivation of Listeria monocytogenes in
ravioli. Lett. Appl. Microbiol. 8:173–175.
7. Beuchat, L.R., R.E. Brackett, D.Y.-Y. Hao, and D.L. Conner. 1986. Growth and thermal inactivation of Listeria monocytogenes in cabbage and cabbage juice. Can. J. Microbiol. 32:791–795.
8. Boyle, D.L., J.N. Sofos, and G.R. Schmidt. 1990. Thermal destruction of Listeria monocytogenes in a meat slurry and in
ground beef. J. Food Sci. 55:327–329.
9. Bradshaw, J.G., J.T. Peeler, J.J. Corwin, J.M. Hunt, and R.M. Twedt. 1987. Thermal resistance of Listeria monocytogenes
in dairy products. J. Food Protect. 50:543–544.
10. Boerlin, P., J. Rocourt, F. Grimont, C. Jacquet, and J.-C. Piffaretti. 1992. Listeria ivanovii subsp. londoniensis subsp. nov.
Int. J. Syst. Bacteriol. 42:69–73.
11. Bradshaw, J.G., J.T. Peeler, J.J. Corwin, J.M. Hunt, J.T. Tierney, E.P. Larkin, and R.M. Twedt. 1985. Thermal resistance
of Listeria monocytogenes in milk. J. Food Protect. 48:743–755.
12. Buchanan, R.L., and L.A. Klawitter. 1990. Effects of temperature and oxygen on the growth of Listeria monocytogenes
at pH 4.5. J. Food Sci. 55:1754–1756.
13. Bunning, V.K., R.G. Crawford, J.T. Tierney, and J.T. Peeler. 1990. Thermotolerance of Listeria monocytogenes and
Salmonella Typhimurium after sublethal heat shock. Appl. Environ. Microbiol. 56:3216–3219.
14. Bunning, V.K., C.W. Donnelly, J.T. Peeler, E.H. Briggs, J.G. Bradshaw, R.G. Crawford, C.M. Beliveau, and J.T.
Tierney. 1988. Thermal inactivation of Listeria monocytogenes within bovine milk phagocytes. Appl. Environ. Microbiol.
54:364–370.
The view in Germany is that zero tolerance is not only unrealistic but unnecessary, and foods are
placed in four risk levels somewhat along the lines of Canada. Products that contain >10
4 /g are subject
to an automatic recall.
Australia requires the absence of L. monocytogenes in 5 × 25-g samples for many cheeses. France requires no L. monocytogenes in 25-g samples of foods for at-risk individuals. The French position seems
to be that it is unrealistic to expect no L. monocytogenes in raw foods. It has been noted that the presence
of this organism in food processing environments is inevitable, especially those for finished products;
and that while the risks of final product contamination can be reduced, they cannot be eliminated.
125
The International Commission on Microbiological Specification for Foods (ICMSF) has concluded
that if this organism does not exceed 100/g of food at point of consumption, the food is considered
acceptable for individuals who are not at risk (see FSO in Chapter 20). The ICMSF endorses the use
of HACCP (see Chapter 21), and places L. monocytogenes in plan stringency cases nos. 10, 11, and
12 (see Table 21–4). The two-class sampling plan for case 10 is n = 5, c = 0; for cases 11, n = 10,
c = 0; and for case 12, n = 20, c = 0. For the years 1994–1998, L . monocytogenes was responsible
for 61% of the 1,328 food product recalls in the United States followed by 11% for salmonellae.
132
However, it is not correct to assume that all recalled foods would have caused listeriosis cases had
they been sold. As noted above, not all strains of this organisms cause human illness; and RTE meat
and poultry products are not handled the same way by different consumers.
REFERENCES
1. Ade, N., S. Steinmeyer, M.J. Loessner, H. Hof, and J. Kreft (Technical University of Munich, Weihenstephan, Freising,
Germany). 1991. Personal communication.
2. Anton, W. 1934. Kritisch-experimenteller Beitrag zur Biologie des Bacterium monocytogenes. Mit basonderer Beruecksichtigung seiner Beziehung zur infektiosen Mononucleose des Menschen. Zbl. Bakteriol. Abt. I. Orig. 131:89–103.
3. Audurier, A., and C. Martin. 1989. Phage typing of Listeria monocytogenes. Int. J. Food Microbiol. 8:251–257.
4. Baldridge, J.R., R.A. Barry, and D.J. Hinrichs. 1990. Expression of systemic protection and delayed-type hypersensitivity
to Listeria monocytogenes is mediated by different T-cell subsets. Infect. Immun. 58:654–658.
5. Bartlett, F.M., and A.E. Hawke. 1995. Heat resistance of Listeria monocytogenes Scott A and HAL 957E1 in various
liquid egg products. J. Food Protect. 58:1211–1214.
6. Beuchat, L.R., and R.E. Brackett. 1989. Observations on survival and thermal inactivation of Listeria monocytogenes in
ravioli. Lett. Appl. Microbiol. 8:173–175.
7. Beuchat, L.R., R.E. Brackett, D.Y.-Y. Hao, and D.L. Conner. 1986. Growth and thermal inactivation of Listeria monocytogenes in cabbage and cabbage juice. Can. J. Microbiol. 32:791–795.
8. Boyle, D.L., J.N. Sofos, and G.R. Schmidt. 1990. Thermal destruction of Listeria monocytogenes in a meat slurry and in
ground beef. J. Food Sci. 55:327–329.
9. Bradshaw, J.G., J.T. Peeler, J.J. Corwin, J.M. Hunt, and R.M. Twedt. 1987. Thermal resistance of Listeria monocytogenes
in dairy products. J. Food Protect. 50:543–544.
10. Boerlin, P., J. Rocourt, F. Grimont, C. Jacquet, and J.-C. Piffaretti. 1992. Listeria ivanovii subsp. londoniensis subsp. nov.
Int. J. Syst. Bacteriol. 42:69–73.
11. Bradshaw, J.G., J.T. Peeler, J.J. Corwin, J.M. Hunt, J.T. Tierney, E.P. Larkin, and R.M. Twedt. 1985. Thermal resistance
of Listeria monocytogenes in milk. J. Food Protect. 48:743–755.
12. Buchanan, R.L., and L.A. Klawitter. 1990. Effects of temperature and oxygen on the growth of Listeria monocytogenes
at pH 4.5. J. Food Sci. 55:1754–1756.
13. Bunning, V.K., R.G. Crawford, J.T. Tierney, and J.T. Peeler. 1990. Thermotolerance of Listeria monocytogenes and
Salmonella Typhimurium after sublethal heat shock. Appl. Environ. Microbiol. 56:3216–3219.
14. Bunning, V.K., C.W. Donnelly, J.T. Peeler, E.H. Briggs, J.G. Bradshaw, R.G. Crawford, C.M. Beliveau, and J.T.
Tierney. 1988. Thermal inactivation of Listeria monocytogenes within bovine milk phagocytes. Appl. Environ. Microbiol.
54:364–370.