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Bacteria standards of merluccius capensis / paradoxus (Cape Hake) and other deepsea whitefish products
Author(s)
Vennemann, Ingo Heinrich
Date Issued
1996
Type
Thesis
Publisher
University of Pretoria
Abstract
This study analysed the bacteria numbers of Hake products
manufactured at 6 different levels of processing complexity,
analyses were conducted at 20°C on Salt Water Agar (SWA) for a
48h incubation period. This enumeration method was suitable
for indicating time and temperature related abuse in the
processing system. This method was sensitive in indicating the
level of processing complexity. The aerobic bacteria
enumerations at 20°C (SWA) were compared to the current EU/FDA
(European Union/Federal Drug Administration USA) standard
procedure testing samples on Plate Count Agar, (PCA) incubated
at 30 - 35°C. The method using SWA incubated at 20°C provided
better and more accurate bacterial counts under "good" and
"poor" manufacturing practice. The hurdle concept was applied, using gamma irradiation,
temperature (Time), chemical preservatives and Vacuum
packaging in an attempt to prolong the shelf life of fresh,
uncooked Cape hake and Kingklip products. Radurization was
effective only when the treated product was kept at
refrigerated temperatures. Temperature was the most important
control measure in extending the shelf life of the products.
No shelf life extension was achieved with the use of chemical
preservatives. Vacuum packaging was not effective in
prolonging shelf life of the products and did not show any
benefit when compared to oxygen permeable vacuum
(microaerophilic) packaging.
Determination of the total aerobic viable bacteria numbers at
20°C SWA, were suitable for estimating the shelflife of deepsea
whitefish products.
manufactured at 6 different levels of processing complexity,
analyses were conducted at 20°C on Salt Water Agar (SWA) for a
48h incubation period. This enumeration method was suitable
for indicating time and temperature related abuse in the
processing system. This method was sensitive in indicating the
level of processing complexity. The aerobic bacteria
enumerations at 20°C (SWA) were compared to the current EU/FDA
(European Union/Federal Drug Administration USA) standard
procedure testing samples on Plate Count Agar, (PCA) incubated
at 30 - 35°C. The method using SWA incubated at 20°C provided
better and more accurate bacterial counts under "good" and
"poor" manufacturing practice. The hurdle concept was applied, using gamma irradiation,
temperature (Time), chemical preservatives and Vacuum
packaging in an attempt to prolong the shelf life of fresh,
uncooked Cape hake and Kingklip products. Radurization was
effective only when the treated product was kept at
refrigerated temperatures. Temperature was the most important
control measure in extending the shelf life of the products.
No shelf life extension was achieved with the use of chemical
preservatives. Vacuum packaging was not effective in
prolonging shelf life of the products and did not show any
benefit when compared to oxygen permeable vacuum
(microaerophilic) packaging.
Determination of the total aerobic viable bacteria numbers at
20°C SWA, were suitable for estimating the shelflife of deepsea
whitefish products.
Additional information
Thesis (PhD (Microbiology))--University of Pretoria, 1996.
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50003784_Vennemann_IH_Dtech_Microbiology_Appsc_1996_50003784.pdf
Description
Thesis
Size
44.87 MB
Format
Adobe PDF
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