BACTERIAL SAFETY AND PRESERVATTON OF "KUNUN ZAKI": A NON-ALCOHOLIC PRODUCT
BACTERIAL SAFETY AND PRESERVATTON OF "KUNUN ZAKI": A NON-ALCOHOLIC PRODUCT
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Date
1997-05
Authors
SOLOMON, ORAKUSI
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Abstract
Bacteriological safety of "kunun zaki", a non-alcoholic
beverage prepared with three different packaging methods was
carried out. Aliquot, of diluted and concentrated samples were
spread on Nutrient agar for total aerobir. plate count, Baird parker
agar for staphylococcal count., Eos in methylene blue agar for
coliform count, Dextrose tryptone agar for Baci1lus count,
Salmonella - shigella agar for isolation of Salmonella and shiqel1 a
and lactose broth for coliform count. Bulk packaged samples in
bowls had the highest contamination with mean total aerobic plate
count of 2.5 x 10* cfu/ml, mean Baci1lus count of 1.0 x 104 cfu/ml
and mean staphylococcal count of 7.3 x 102 cfu/ml. Bottled samples
were least contaminated with mean total aerobic plate count of 9.7
x 105 cfu/ml, mean Baci1lus count of 1.0 x 103 cfu/ml and mean
staphylococcal count of 6.8 x 101 cfu/ml. However cellophane
packaged samples had the highest mean coliform count of 3.6 x 103
cfu/ml while bottled and bulk packaged samples had mean coliform
counts of l.8 x 10J cfu/ml and 1.5x102 cfu/ml respectively. Only
one Salmonella isolate was recorded and other pathogens of concern
such as B cereus, E. col i and S. aureus were found to be present .
Shigella spp was not isolated. Bulk packaging and cellophane
packaging of "kunun zaki" should be discouraged due to its high
rate of contamination.
Studies on sources of contamination and hazard analysis of
"kunun zaki" preparation was carried out on three producers around
Zaria. It revealed some sanitary deficiencies to include
inadequate sorting and washing of raw materials, possible faecal
contamination from animals in or around food preparation area, use
of unprotected well water and potential sources of spores from raw
materials and sweetening agents and dust at point of display for
sale. Inadequate boiling. Mixing and seiving of product with hare
hand were also observed as possible mean of contamination.Education
of producers on the importance of hygienic environment, is
imperative.
Laboratory products were prepared containing preservatives
such as acetic acid, benzoic acid, sodium benzoate, sodium citrate
and citric acid at concentrations permitted by national and
international regulations. The control products had no
preservative. At 28+2*C. of storage, sensory analysis by a panel of
six judges revealed that, sodium benzoate alone extended the shelf
life for up to 24 weeks, sodium benzoate/sodium citrate and sodium
benzoate/citrie acid/sodium citrate extended the shelf life for 16
weeks, acetic acid, benzoic acid and sodium citrate lost the effect
after 4 weeks. Citric acid had no preservative effect on "kunun
zaki". The control samples deteriorated after two weeks while the
commercial samples had a shelf life of one day. The preservation
of "kunun zaki" for 24 weeks at ambient temperature is a pointer
that this work could be the basis for a pilot production of bottled
"kunun zaki". Tt is therefore recommended that a starter culture
he developed and controlled industrial production of "kunun zaki"
be encouraged.
Ten R^ cereus isolates were tested for enterotoxin production
using the ligated rabbit, ileal loop test.. Five (50%) were
enterotoxigenic! with mild, moderate and severe enterotoxin
reactions. The severe enterotoxigenic strain was from the bulk
packaged samples. Ten S. aureus isolates were tested for
haemolysis on human and sheep blood agar. Six (60%) were alpha
haemolytic while 4 (40%) were heta haemolytio. This raises serious
public health concern since 6-haemolytic strains are likely to be
human biotypes and more enterotoxigenic than animal biotypes which
are often beta haemolytic.
A study of the resistance patterns of the 37 isolates of B.
cereus, R. coli and S aureus to 16 commonly used antimicrobial
agents showed no significant, difference (P>0.05) in resistance of
isolates from various packaging methods. Overall resistance of 15
strains of E. coli to antimicrobial agents tested were Cephalexin
86.6%, Cefuroxime 79.9% Streptomycin 53.3%. The resistance of 10
strains of S. aureus to tested antimicrobial agents were Penicillin
and Streptomycin 70% each, Sulphafurazole 60%, while the resistance
of 11 strains of B. cereus isolates tested were erythromycin 9.7.3%,
penicillin and oloxacillin 18.2% each.
The predominant multiple resistance patterns for E. coli were
streptomyoin-ampioi11 in 40%, streptomyoin-ampicillin-sulphafurazole
40% and amplici11in-sulphafurazole 33.3%. The common patterns for
S.aureus were sulphafurazole-streptomycin 60%, penicillinsulphafurazole
50%, penioi 11in-ampici11 in 30% and ampioillincloxacillin
20%, while the patterns for B. aureus were penicillinX
ampioillin 18.2% and penici11in-amplicil1in-cloxaoillin 18.2%.
These high percentage resistance to antibiotics may be a reflection
of misuse of these antimicrobial agents in medical and veterinary
practices. The indiscriminate use of antibiotics should be
discouraged to reduce the incidence of drug resistance isolates.
Apart from lead (Pb) content, there were no significant
differences in proximate composition of commercial and laboratory
produced "kunun zaki" but there were nutritional losses in sorghum
and millet due to processing into "kunu". There may therefore, be
the need for enriching "kunun zaki" with nutrients from other
sources during processing or before consumption.
Description
A THESIS SUBMITTED TO THE
POSTGRADUATE SCHOOL
AHMADU BELLO UNIVERSITY
ZARIA - NIGERIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF MASTER OF SCIENCE
DEPARTMENT OF MICROBIOLOGY
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY
ZARIA - NIGERIA
Keywords
BACTERIAL,, SAFETY,, PRESERVATTON,, KUNUN ZAKI,, NON-ALCOHOLIC,, PRODUCT