Department of Veterinary disease biology
What determines the risk of growth of
Salmonella after recontamination
of ready to eat heat-treated egg products
Džiuginta Jakočiūn÷
Department of Veterinary disease biology
Introduction
•
Salmonella cause most of food-borne outbreaks in Europe
(EFSA)
•
Eggs and egg products cause most of them.
How??
•
Raw eggs used in ice cream, mayonaise, eaten
undercooked.
•
Solution – pasteurization!!
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Department of Veterinary disease biology
Pasteurized egg products
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Department of Veterinary disease biology
However…
It is very dangerous to assume something is safe.
Prevalence:
•
0.3 % pasteurized egg products were positive for
Salmonella in 2011 in USA (FSIS). No outbreaks though.
•
1.7 % in Japan (Hara-Kudo & Takatory, 2009)
Outbreaks in Europe :
•
2007, from pasteurized egg white and yolk used for
chocolate mousse, pasteurized egg white for desert and
salmon mousse.
•
2012m from pasteurized egg white (ready to drink)
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Department of Veterinary disease biology
How Salmonella appears in heat-treated products
•
Products can be re-contaminated
•
Salmonella can survive pasteurization (resistance or failure)
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Department of Veterinary disease biology
Factors to be considered
•
Product type (natural composition)
•
Temperature (before pasteurization and after)
•
Salt
•
Preservatives
•
Inoculum level
•
Serovars
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Department of Veterinary disease biology
Product type (natural composition) I
20°C
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Department of Veterinary disease biology
Product type (natural composition) II
Survival of Salmonella in egg white
Lg, CFU/ml
5,00
4,50
S. Enteritidis
4,00
S. Tennessee
3,50
S. Typhimurium
20°C
3,00
pasteurization
2,50
2,00
0
100
200
Time, h
300
30°C
400
20°C
Adapted from McQuestin et.al.,
2010, Food Microbiology
Adapted from Baron et.al., 1999, J. of Food Protection
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Department of Veterinary disease biology
Product type (natural composition) III
pasteurization
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Department of Veterinary disease biology
Temperature (before)
LG CFU/ml
Whole egg
10
9
8
7
6
5
4
3
2
1
0
Whole egg
0
20
40
60
80
time, h
Adapted from Singh 2011. J. of Food Science.
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Adapted from Sakha & Fujikawa, 2013.
Biocontrol Science.
Department of Veterinary disease biology
Temperature (after)
Adapted from McQuestin et.al.,
2010, Food Microbiology
Adapted from Sakha & Fujikawa, 2013.
Biocontrol Science.
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Department of Veterinary disease biology
Salt
S.Typhimurium
Pasteurized salted (10%)
yolks, 30°C
Adapted from Musgrove et. al. 2009, J. of Food Protection
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Department of Veterinary disease biology
Preservatives
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Department of Veterinary disease biology
Inoculum size
S. Enteritidis
Pasteurized
liquid egg. 24°C
Addapted from Sakha & Fujikawa, 2012. Biocontrol Science.
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Department of Veterinary disease biology
LG CFU/ml
Serovar
Department of Veterinary disease biology
Conclusions / Recommendations
•
Avoid abused temperatures before pasteurization
•
Control pasteurization temperatures
•
Avoid cross contamination from raw material and equipment
•
Cool products immediately after pasteurization
•
Salt or other preservatives can be used to prolong shelf life
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Department of Veterinary disease biology
Thanks for your attention
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