10/18/2017 Learning Objectives Food 1.Use basic biochemical characteristics to identify Microbiology Listeria monocytogenes 2.Understand what conditions in foods favor the Chapter 13 AN INTRODUCTION growth of L.monocytogenes 3.Recognize,from symptoms and time of onset,a case of foodborne illness caused by L.monocytogenes Listeria 4.Choose appropriate interventions to prevent L. monocytogenes monocytogenes growth 5.Identify environmental sources of L.monocytogenes 6.Understand the role of L.monocytogenes toxin(s) and virulence factor(s)in causing foodborne illness Outbreak Outbreak 1998-1999 Sporadic outbreaks 1998-1999 ·Spring summer1998 ·November1998 hot dog plant had unusually high numbers -a 31-yr-old camp counselor died in Ohio of Listeria genetic fingerprints of the strains were identical ·July1998 so they must have eaten a similar food -air conditioning unit thought to be the ·Early December1998 source of Listeria was removed -hot dogs were statistically implicated as the cause ·October1998 ·Mid December1998 -CDC investigated 4 listeriosis cases from hot dogs from Sara Lee's Bil Mar Foods Plant were implicated Tennessee -4 people dead -a 74-yr old woman who loved hot dogs died plant stopped shipping the hot dogs additional cases came in from other states10/18/2017 1 Chapter 13 Listeria monocytogenes Learning Objectives 1. Use basic biochemical characteristics to identify Listeria monocytogenes 2. Understand what conditions in foods favor the growth of L. monocytogenes 3. Recognize, from symptoms and time of onset, a case of foodborne illness caused by L. monocytogenes 4. Choose appropriate interventions to prevent L. monocytogenes growth 5. Identify environmental sources of L. monocytogenes 6. Understand the role of L. monocytogenes toxin(s) and virulence factor(s) in causing foodborne illness Outbreak 1998-1999 Sporadic outbreaks • Spring summer 1998 – hot dog plant had unusually high numbers of Listeria • July 1998 – air conditioning unit thought to be the source of Listeria was removed • October 1998 – CDC investigated 4 listeriosis cases from Tennessee - a 74-yr old woman who loved hot dogs died - additional cases came in from other states Outbreak 1998-1999 • November 1998 - a 31-yr-old camp counselor died in Ohio - genetic fingerprints of the strains were identical so they must have eaten a similar food • Early December 1998 - hot dogs were statistically implicated as the cause • Mid December 1998 - hot dogs from Sara Lee’s Bil Mar Foods Plant were implicated - 4 people dead - plant stopped shipping the hot dogs