Affiliation:
1. Laboratory of Microbiology, Department of Biochemistry, Physiology and Microbiology, Ghent University, Ghent, Belgium
Abstract
ABSTRACT
Bacterial
contamination of gelatin is of great concern. Indeed, this animal
colloid has many industrial applications, mainly in food and
pharmaceutical products. In a previous study (E. De Clerck and P. De
Vos, Syst. Appl. Microbiol.
25:
611-618), contamination of a
gelatin production process with a variety of gram-positive and
gram-negative bacteria was demonstrated. In this study, bacterial
contamination of semifinal gelatin extracts from several production
plants was examined. Since these extracts are subjected to harsh
conditions during production and a final
ultrahigh-temperature treatment, the bacterial load at this
stage is expected to be greatly reduced. In total, 1,129 isolates were
obtained from a total of 73 gelatin batches originating from six
different production plants. Each of these batches was suspected of
having bacterial contamination based on quality control testing at the
production plant from which it originated. For characterization and
identification of the 1,129 bacterial isolates, repetitive-element
PCR was used to obtain manageable groups. Representative
strains were identified by means of 16S rRNA genesequencing, species-specific
gyrB
PCR, and
gyrA
and
rpoB
sequencing and were tested for gelatinase activity. The
majority of isolates belonged to members of
Bacillus
or
related endospore-forming genera. Representative strains were
identified as
Bacillus cereus
,
Bacillus coagulans
,
Bacillus fumarioli
,
Bacillus amyloliquefaciens
,
Bacillus licheniformis
,
Bacillus pumilus
,
Bacillus sonorensis
,
Bacillus subtilis
,
Bacillus
gelatini
,
Bacillus thermoamylovorans
,
Anoxybacillus
contaminans
,
Anoxybacillus flavithermus
,
Brevibacillus agri
,
Brevibacillus borstelensis
, and
Geobacillus stearothermophilus
. The majority of these species
include strains exhibiting gelatinase activity. Moreover, some of these
species have known pathogenic properties. These findings are of great
concern with regard to the safety and quality of gelatin and its
applications.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology