Role of traditional cooking methods in controlling S. aureus and L. monocytogenes in shrimp

Nosier, Shireen M.; Shabana, EL-Syed S.E.; Abdelmonem, Mohamed A.

doi:10.21608/bvmj.2015.32739

Role of traditional cooking methods in controlling S. aureus and L. monocytogenes in shrimp

Document Type : Original Article

Authors

¹ Animal health research institute

² Central Laboratory of residual analysis pesticides and heavy metals in food

10.21608/bvmj.2015.32739

Abstract

This study was planned out to evaluate the effectiveness of different traditional cooking methods on the
viability of L. monocytogenes and S. aureus by contaminating unpeeled whole shrimp samples with 2.4x
10⁶ cfu/g for L. monocytogenes and 4x10⁶ cfu/g for S.aureus. Also the effect of refrigeration at 4c°on
the viable count of S. aureus and L. monocytogenes, was studied, S. aureus and L. monocytogene counts
were 1x10⁶and 3x10⁶ cfu/g after one day and 2.7x10⁷ and 2x10⁵ cfu/g after two days of refrigeration,
respectively. This indicated that the refrigeration temperature decreased S. aureus count but increased
L. monocytogenes count. While, the traditional cooking by boiling for inoculated shrimp revealed that,
the boiling in different stages at zero day, first and second day of refrigeration decreased the count to
<10 cfu/g for both. Microwave oven treatment of the samples resulted in destruction of both S. aureus
and L. monocytogenes cells decreasing the count from about 106cfu/g to <10cfu/g. With the exposure of
inoculated shrimp to different traditional cooking temperatures within one min for each temperature of
60°c decreased L. monocytogenes count to be 1.7x10² cfu/g, and S. aureus count to 2x104 cfu/g. At 80°c
temperature effect on L. monocytogenes count decreased to be <10 cfu/g and S. aureus count to be 3x10
cfu/g.

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