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MICROBIAL FOOD SAFETY RISK: COOKED AND SMOKED SAUSAGES AS A POTENTIAL SOURCE

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Food borne diseases are perhaps the most widespread health problem in the contemporary world and an important cause of reduced economic productivity. Food safety risks associated with meat and meat products has been widely documented. This study investigated the microbial risks associated with cooked and smoked sausages sold in Accra, Ghana. A total of forty (40) samples of sausages were obtained for the study. Twenty (20) samples were purchased from a sausage producing factory in Accra and Twenty (20) from a shopping mall where mainly imported products are sold. Samples were analyzed following conventional techniques. Total viable count, coliform count, Staphylococcus aureus count, Lactic acid bacteria (LAB) count and mould counts were determined. Pathogenic contaminants were also identified. The results indicated that total viable count on locally produced sausages (log108.60-8.88±0.10) and imported sausages (log108.51-8.80±0.10) were not significantly different (p=0.180) and that both were above the accepted standard (log10 6.0). Similarly, Coliform counts on locally produced products (log105.53-5.98±0.19) and imported (log105.53-5.59±0.02) were above the standard (log10 4.0) and their difference was not significant (p=0.317). Mould counts from both sources were however, below the Standard (<log10 4.0). LAB counts were 2.84-3.54±0.14 in locally produced sausages and 5.3-5.66±0.2 for imported sausages (P= 0.02). Pathogens like Staphylococcus aureus, E.coli, Clustridium, Klebsiella and Proteus were isolated from both locally produced and imported sausages and moulds isolated included Aspergillus, Penicillin and Mucor. In conclusion, the current study has demonstrated that cooked and smoked sausages serve as a potential hazard of pathogenic food borne bacteria and should be well cooked before consumption.
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IJBPAS, March, 2012, 1(2): 99-107
ISSN: 2277–4998
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MICROBIAL FOOD SAFETY RISK: COOKED AND SMOKED SAUSAGES AS A
POTENTIAL SOURCE
MAHAMI T1*, AMAFU-DEY H 2 AND ODONKOR ST3
1: Biotechnology and Nuclear Agriculture Research Institute (BNARI), Ghana Atomic Energy
Commission (GAEC), P.O. Box LG 80, Legon, Ghana
2: Animal Research Institute (ARI), Council for Scientific and Industrial Research (CSIR), P.O.
Box 20, Achimota, Ghana
3: Radiological and Medical Sciences Research Institute (RAMSRI), Ghana Atomic Energy
Commission, P.O. Box LG 80, Legon, Ghana
*Corresponding author: E-mail: teem2002gh@yahoo.com, tmahami@yahoo.com; Tel. No;
+233249606418
ABSTRACT
Food borne diseases are perhaps the most widespread health problem in the contemporary world
and an important cause of reduced economic productivity. Food safety risks associated with meat
and meat products has been widely documented. This study investigated the microbial risks
associated with cooked and smoked sausages sold in Accra, Ghana. A total of forty (40) samples
of sausages were obtained for the study. Twenty (20) samples were purchased from a sausage
producing factory in Accra and Twenty (20) from a shopping mall where mainly imported
products are sold. Samples were analyzed following conventional techniques. Total viable count,
coliform count, Staphylococcus aureus count, Lactic acid bacteria (LAB) count and mould
counts were determined. Pathogenic contaminants were also identified. The results indicated
that total viable count on locally produced sausages (log108.60-8.88±0.10) and imported sausages
(log108.51-8.80±0.10) were not significantly different (p=0.180) and that both were above the
accepted standard (log10 6.0). Similarly, Coliform counts on locally produced products
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(log105.53-5.98±0.19) and imported (log105.53-5.59±0.02) were above the standard (log10 4.0)
and their difference was not significant (p=0.317). Mould counts from both sources were
however, below the Standard (<log10 4.0). LAB counts were 2.84-3.54±0.14 in locally produced
sausages and 5.3-5.66±0.2 for imported sausages (P= 0.02). Pathogens like Staphylococcus
aureus, E.coli, Clustridium, Klebsiella and Proteus were isolated from both locally produced and
imported sausages and moulds isolated included Aspergillus, Penicillin and Mucor.
In conclusion, the current study has demonstrated that cooked and smoked sausages serve as a
potential hazard of pathogenic food borne bacteria and should be well cooked before
consumption.
Keywords: Microbiological, Food safety, Sausages, Bacteria, Moulds.
INTRODUCTION
Food borne diseases are perhaps the most
widespread health problem in the
contemporary world and an important cause
of reduced economic productivity. The
number of cases, outbreaks, type of food and
micro-organisms involved and the cost of
food borne diseases to a nations economy as
well as the potential negative impact of lack
of food safety in a nation’s food supply have
been documented [1, 2]. Meat is very
perishable due to the sufficient nutrients it
contains that support the growth of
microorganisms [3] especially minced meat
because it presents an increased surface area
that can easily be contaminated during the
mixing or mincing operation [4].
There is growing consumer interest in ready-
to-eat meat products including cooked and
smoked sausages which account for
approximately 85% of all sausages produced
today [5, 6]. Evidence indicate that cooked
and smoked sausages are very perishable, and
must be sold not later than 1–2 days after
production and/or refrigerated until time of
consumption, or they expire [7, 6].
Furthermore, the type of technology
employed in sausage production is said to
influence the type of microbial contaminants
which gain access into the sausage from meat,
the sausage casing, spices and other
ingredients, from environment, equipment,
and handlers during processing [6]. The
quality and in particular the safety of sausages
is said to intrinsically rest with the
microbiology of the production processes [8].
Unfortunately, traditional techniques are
employed for sausage production in some
developing countries without regard to Good
Manufacturing Practices (GMP) and
principles of Hazard Analysis and Critical
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Control Point (HACCP). Additionally,
inadequate cooling as well as prolonged
keeping of the products beyond their shelf life
are other significant factors that affect their
microbiological safety.
Food borne pathogens like E.coli, Listeria,
Salmonella, Staphylococcus etc have all been
isolated from different types of sausages [6]
in different parts of the world but published
microbiological information on sausages from
Ghanaian markets and food shops is not
readily available. The objective of this study
was to evaluate the microbial risk associated
with sausages sold in Accra, Ghana.
MATERIALS AND METHODS
Sample collection
A total of 40 sausage samples were collected
(20 samples from a retail supermarket where
the products were held refrigerated and 20
from a sausage producing factory). Samples
were transported packed in ice to the
laboratory and analyzed immediately.
Culture, Enumeration, Isolation and
Identification
The standard pour plate technique as
described by the [9] was applied to evaluate
the total aerobic plate counts, coliform counts,
staphylococcus counts, Lactic Acid Bacteria
(LAB) counts and yeast and mould counts of
samples. Plate Count Agar (PCA) (Oxoid)
was used for total count, Violet Red Bile Agar
(VRBA) (Oxoid) for coliform count, Baired
Parker agar (Oxoid) for staphylococcus
aureus count, De Man Rogosa Sharpe (MRS)
agar (Oxoid) for LAB and Sabouraud
dextrose agar (Oxoid) for yeast and moulds.
All media were prepared following the
manufacturer’s instructions and incubation
was done at 370C for 48h for bacteria cultures
and at 280C for 48h for mould cultures.
Samples were also screened for food borne
bacteria pathogens applying conventional
methods of biochemical techniques leading to
identification. Incubation period of mould
cultures was extended to 7 days for
identification based on physical morphology
and microscopy.
For pH measurement, 10 g of test samples
were minced aseptically in 90 ml of distilled
water using a stomacher. After the
homogenization, pH values were determined
with digital pH-meter (WTW, Germany).
Statistical Analysis
A Statistical Package for the Social Sciences
(SPSS) was used to analyze data and p<0.05
was considered to be significant.
RESULTS
Results of 20 samples of locally produced
sausages and 20 samples of imported
sausages are presented in Tables 1, 2 and 3.
Bacteria isolated and identified from locally
and imported sausages are presented in Table
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2 below. Moulds isolated and identified from
locally and imported sausages are presented
in Table 3 below.
Table 1: pH and Microbial Counts on Sausages Sold in Accra
Source
of
samples
pH Bacterial and mould counts (Log10 CFU/g)
Total count Coliform count S. aureus count LAB count Mould count
Importe
d
6.3±0.05 8.51-8.80±0.30 5.53-5.59±0.02 <1.00 EST 5.3-5.66±0.2 <1.00 EST
Local 6.43±.0.09 8.60-8.88±0.27 5.53-5.98±0.19 1.85-2.15±0.13 2.84-
3.54±0.14
<1.00 EST
Values are range ± SD of 20 replicates, EST-estimated count i.e. when counts were less than 30 CFU/g
(minimum resolution of the enumeration method)
Table 2: Occurrence of Bacteria Isolates in Sausages
Isolates (Genera) Occurrence in samples (%)
(Imported) (Local)
Clostridium 0(0) 6(30)
Escherichia 4(20) 8(40)
Klebsiella 2(10) 2(10)
Micrococcus 4(20) 4(20)
Proteus 2(10) 6(30)
Staphylococcus 2(10) 6(30)
Streptococcus 4(20) 4(20)
Table 3: Occurrence of Mould Isolates in Sausages
Isolates (Genera) Occurrence in samples (%)
(Imported) (Local)
Aspergillus 2(10) 10(50)
Penicillium 0(0) 10(50)
Mucor 2(10) 4(20)
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The results in Table 1 show that pH of locally
produced sausages was higher 6.43±.0.09
than that of imported sausages 6.30±0.05 and
the difference was statistically significant
(p=0.042). Generally, microbial counts were
higher in locally produced sausages than in
imported ones. Total cell count realized in
locally produced sausages was 8.60-
8.88±0.102 as compared to a lower total cell
count of 8.51-8.80±0.104 in imported
products (Table 1) but the difference was
statistically insignificant (p=0.180). Similarly,
coliform counts and Staphylococcus aureus
counts were higher in locally produced
sausages than in imported sausages (Table 1).
A coliform count of 5.53-5.59±0.021 was
observed in imported products whereas a
count of 5.53-5.98±0.190 was recorded in
locally produced sausages and there was no
significant difference (p=0.317). In the case
of Staphylococcus aureus, whereas a count of
1.85-2.15±0.13 was realized in local sausages,
counts in imported sausages were <1.00 EST
(Table 1).
LAB counts on samples however, yielded
2.84-3.54±0.14 in locally produced sausages
and 5.3-5.66±0.2 for imported sausages (P=
0.02) indicating counts on imported sausages
were higher (Table 1). Mould counts were
low i.e. below 30 CFU/g of sample.
The results (Table 2) shows that the most
isolated bacteria in imported sausages were
E.coli (20%), Micrococcus (20%) and
Streptococcus (20%). Other bacteria genera
isolated from imported sausages included
Klebsiella (10%), Proteus (10%) and
Staphylococcus (10%). In the case of locally
produced sausages, the most isolated bacteria
were E.coli (40%), followed by Clostridium
(30%), Proteus (30%) and Staphylococcus
(30%). The others were Micrococcus (20%),
Streptococcus (20%) and Klebsiella (10%)
(Table 2).
Moulds isolated from imported and locally
produced sausages similarly differed.
Whereas Aspergillus (50%) and Penicillin
(50%) were the most isolated in locally
produced sausages, Aspergillus (10%) and
Mucor (10%) were mostly isolated from
imported sausages (Table 3). Mucor occurred
in only 20% of locally produced sausages
(Table 3).
DISCUSSIONS
This study revealed that both locally produced
and imported sausages sampled were of
unsatisfactory microbiological quality. For
example, total cell counts of log108.51-
8.80±0.10 and log108.60-8.88±0.10 observed
respectively in imported and locally produced
sausages (Table 1) were above the
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microbiological standards ( 6.0 log10 cfu/g)
set by [10] and [11]. Even though total viable
counts of locally produced sausages were
generally higher than that of imported
sausages, the difference in counts was
statistically insignificant (p=0.180). This
finding here is comparable to earlier work by
[12] on fermented meat products in Ghana
and [13] on microbial contaminants of
sausages sold in two Nigerian cities. The
reasons for the high total counts observed in
this study may be due to post processing
microbial contamination coupled with
irregular cold storage conditions. According
to [7] one easy way to increase sausage shelf
life is to lower the temperature of all rooms
needed in the processing, and storage of
meats and sausages.
High coliform counts; 5.53-5.59±0.02 in
imported sausages and 5.53-5.98±0.19 in
locally produced ones with no significant
difference (p=0.317) observed in this study
(Table 1) were both above the standard of
4.0 log10 cfu/g [10, 11] in agreement with
[13].The coliform count has been widely
accepted as indicator of faecal contamination
and therefore the indicator of the possible
presence of pathogens of enteric origin, e.g.,
Salmonella [4]. High counts observed in this
study therefore suggests that the products
were produced and distributed under poor
sanitary conditions possibly coupled with
temperature abuse during storage that allowed
the microbes to proliferate. According to [8]
storage of sausages below 8°C helps
minimize the risk of bacterial growth as
certain bacteria are either unable to grow
below this temperature or grow at such a slow
rate that they may not pose a risk. The
slaughter of animals under unhygienic
background, use of contaminated water
followed by production of sausages without
adhering to good manufacturing practices
may have been some of the sources of these
coliform organisms. Occurrence of specific
coliforms like E. coli (20%) in imported
products and (40%) in locally produced
products (Table 2) confirms the unhygienic
background of sausages sampled.
Staphylococcus aureus count of 1.85-
2.15±0.13 was realized in local sausages
whiles imported sausages accounted for <1.00
EST counts (Table 1). Staphylococcus aureus
is present in the mucous membranes, nose,
and throat and on skin and hair of many
healthy individuals. Infected wounds, lesions
and boils [4]. The presence of high counts of
staphylococci particularly in locally produced
sausages is therefore suggestive of
contamination from the skin, mouth and nose
of food handlers or inadequately cleaned
equipment. Higher staphylococci counts are
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generally a good indication of poor hygiene
and poor temperature control and may suggest
the presence of enterotoxin producing strains
of S. aureus [14].
This study observed LAB counts of 2.84-
3.54±0.14 in locally produced sausages and
5.3-5.66±0.2 for imported sausages with a
significant difference (P= 0.02) (Table 1) a
suggestion that imported products had lower
pH values due to fermentation of LAB [15].
This trend was confirmed by readings of pH
values of 6.3±0.05 recorded for imported
products and a value of 6.43±.0.09 for local
products (Table 2), a low pH and/or low LAB
count improves the keeping quality of sausage
due to the fact that some spoilage bacteria are
not able to grow in lower pH mediums [7].
Specific LAB identified were Micrococcus
and Streptococcus (Table 2).
Yeast and mould counts observed in this
study were within acceptable microbiological
standards of <4.0 log10 cfu/g (Table 1). This
may probably be due to the high moisture
content of the products and high temperatures
at the time this work was carried out which
together may have favored bacteria growth
than moulds. Evidence indicate that mould
formation on sausage products is generally
the result of keeping them in damp, poorly
ventilated rooms or of improper packaging
which may result in spoilage of the product
[6].
Isolation of pathogens like Staphylococcus
aureus, E. coli, and Klebsiella from sausages
(Table 2) indicates poor handling of the
products after production resulting in
contamination. Contamination with
Clustridium however is said to be as a result
of inappropriate temperature and time during
smoking of the product [6]. All isolates
(Table 2) are capable of causing food borne
disease [16, 17]. The primary function of
Micrococcus and Streptococcus however are
lactose acid production for fermentation of
sausage [4]. Aspergillus, Penicillium and
Mucor species are noted to be responsible for
spoilage on sausages [4]. They are especially
apt to establish themselves on sausages, the
surface of which they cover first with their
white and then grey or grayish-green tufts. It
is clear from this study as with any food
product, that proper worker hygiene, raw
ingredient handling and storage procedures,
and the final product handling and storage
procedures are essential to control product
contamination by organisms that are harmful
to humans
In conclusion, the current study has
demonstrated that cooked and smoked
sausages serve as a potential hazard of
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pathogenic food borne bacteria and they
should be well cooked before consumption.
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... Some other studies assessed CPS loads, even reported as S. aureus counts, in readyto-eat foods in the African continent. Although Mahami et al. [41] found low contamination of cooked and smoked sausages, reporting S. aureus loads ranging from 1.85 to 2.15 Log CFU/g in samples purchased from a factory in Ghana (in Accra city) and less than 1 Log CFU/g in samples from a shopping mall, Oguttu et al. [42], analyzing readyto-eat chicken sold in informal markets in South Africa (in Tshwane Metropolitan City), reported the presence of unsatisfactory quality samples with loads of S. aureus greater than 3 Log CFU/g, and an overall mean of 3.6 Log CFU/g. Similarly, Shiningeni et al. [43] found ready-to-eat beef and chicken meats of unsatisfactory quality, with loads of S. aureus equal or greater than 3 Log CFU/g, that were purchased from street vendors in Namibia (Windhoek city). ...
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... The batter is filled in the casings then smoking and cooking is applied. Even though the cooking process decreases the microbial load, recontamination often takes place and there are studies show that pathogens, such as E.coli, S.aureus and Salmonella, were isolated from ready-to-eat frankfurters [9,0,11]. Moreover, the pH of frankfurters decreases gradually throughout the storage due to the activity of lactic acid bacteria [12], thus sub-lethal pH might aid STEC to form acid tolerance responses if the product is contaminated with STEC after cooking process. ...
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... Outbreaks of E. coli O157 and non-O157 STECs have been reported for various types of sausages (Normanno et al. 2002(Normanno et al. , 2004Ethelberg et al. 2009). Many reports show that frankfurters can be contaminated with various pathogens alongside with E.coli (Mahami et al. 2012;Bolghari 2016;Samaha et al. 2016) during post-heat process handling, ie. casing removal, slicing, packaging (Güngör and Gökoglu 2010). ...
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