66
Microorganisms Associated with Pearl Millet Cultivars
at Various Malting Stages
M. H. Badau
*
Department of Food Science & Technology, University of Maiduguri, P. M. B. 1069,
Maiduguri, Nigeria
Microbiological analysis of samples taken at various stages of malting pearl millet cultivars was
investigated. The results indicated that total bacterial count, mould count, staphylococcal count, coliform
count and yeast count ranged from 4.08 to 5.28 log
10
CFU/g, 2.50 to 3.71, 1.78 to 4.20, 2.65 to 3.65, and 2.54
to 3.70, respectively. The predominant microorganism in unmalted grain was Bacillus subtilis, while green
malt had Rhizopus arrhizus and Proteus vulgaris as the predominant microorganisms. Rhizopus arrhizus
occurred at a higher frequency (75.0%) in dried and polished malts. Most of the microorganisms were widely
distributed, particularly Torulopsis glabrata, Lactobacillus plantarum and Streptococcus lactis. The
population of microorganisms isolated from malting stages was not high enough to produce effective dose.
However, there is the need to adopt strict hygiene practices to prevent malt from being sources of
contamination to malt based foods.
Pearl millet is an important food for millions of people
inhabiting the semi-arid tropics and is a major source of
calories and vital component of food security in the semi-
arid areas in the developing world (FAO and ICRISAT,
1996). The grain is processed in so many ways for
preparation of various food products. Some of the products
include cooked whole grain, thin and thick porridges, steam
cooked grits (couscous, burabosko), kunun zaki, tuwo and
fura(Nkama and Ikwelle, 1997; Jideani et al., 1999, 2001,
2002). Pearl millet can also be malted to produce alcoholic
beverages and weaning food (Desikachar, 1980; Mosha and
Svanberg, 1983; AHRTAG, 1990). There are a lot of
investigations carried out on physicochemical and malting
properties of pearl millet in recent times. The
physicochemical and water absorption characteristics of
pearl millet cultivars have been published by Badau et al.
(2002, 2005a). Steep-out moisture, malting loss, diastatic
power (Badau et al., 2006a), sugars (Badau et al., 2005b),
amylase activity (Badau et al., 2006b), phytic acid content
and hydrochloric extractability of minerals in pearl millet as
affected by germination time and cultivar have also been
published (Badau et al., 2005c). Information with regard to
microbial load of weaning foods or other food products
from malted cereals produced by traditional technologies
(such as malting) are not very adequate in this region. The
incidence of diarrheal disease is high in children during the
weaning stage which could be due to microbial
contamination of food and water (Mathar and Reddy, 1983).
*Corresponding author, mailing address: Department of Food
Science & Technology, University of Maiduguri, P. M. B. 1069,
Maiduguri, Nigeria. Phone: 234-76-977382, Fax: 076-233-039. E-
mail: mamudu_badau@yahoo.com
Badau et al. (2006c) have documented the effect of addition
of malt flour from pearl millet cultivars and sorghum on
production, acceptability and microbial evaluation of
weaning food formulations. However, information on the
microorganisms associated with the various malting stages
of these pearl millet cultivars is still inadequate in this area.
Therefore, the objectives of this study were to determine the
microbial load, isolate and identify microorganisms at
various malting stages of pearl millet cultivars.
MATERIALS AND METHODS
Three pearl millet cultivars; SOSAT C-88, ZANGO and
EX-BORNO were obtained from Lake Chad Research
Institute, Maiduguri and International Crops Research
Institute for the Semi-Arid Tropics Experimental station at
Bagauda, Kano, Nigeria. These pearl millet cultivars were
used because they have negligible tannin content (Badau et
al., 2002), high hydrochloric acid extractability of minerals
(Badau et al., 2005c), high sugars content (Badau et al.,
2005 b) and high amylase activities (Badau et al., 2006b)
and generally they have good malting properties(Badau et
al., 2006a). Culture media used were nutrient agar
(International Diagnostics group, PLC, Plancashire BC9
6AU, U.K.) for total bacterial aerobic plate count, mannitol
salt agar (International Diagnostics group, PLC, Plancashire
BC9 6AU, U.K.) for staphylococcal count, sabouraud
dextrose agar (Biotech Laboratories Ltd, 38 Anson Road
Marthesham Heat Ipswich, Suffolk IP5 3RG, U.K.) for
yeast count, MacConkey (International Diagnostics group,
PLC, Plancashire BC9 6AU, U.K.) for coliform count.
Others were Salmonella/Shigella (International Diagnostics
group, PLC, Plancashire BC9 6AU, U.K.) for
Internet Journal of Food Safety, Vol.8, 2006, p. 66-72
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