Resident microbial load, toxigenic potential and possible quality control measures of six imported seasoning powders on the Ghanaian market

Abstract

Assessment of resident microbiological contamination of six imported seasoning powders on the Ghanaian market were studied using three media DRBC, OGYE and PCA. The presence of moulds and yeasts was compared on two media (DRBC and OGYE) at 30ᵒC for 7days and bacteria on PCA at 35ᵒC for 48hr. Determination of elemental compositions and mycotoxin analyses (aflatoxins and ochratoxins) were also analysed using AAS spectrometry and HPLC technique respectively. As a means of eliminating resident microbial load in the seasonings, gamma irradiation doses of 0, 2, 5, and 10KGy were applied at an absorbed dose rate of 1.683KGy/hr. seven genera of fungi (Aspergillus, Cladosporium, Penicillium, Absidia, Eurotium, Rhizopus and Paecilomyces) were isolated from the samples. Aspergillus species (A. candidus, A. flavus, A. niger, A. oryzae, A. sulphureus) predominated over the other species followed by Penicillium (P. corylophilum, P. aurantiogriseum); Cladosporium (C. herbarum, C. macrocarpum) and Rhizopus (R. oryzae, R. stolonifer). The percentage occurrence profile of resident fungi changed after 6months storage. Species of bacteria encountered varied from one seasoning to the other but included Acinetobacter pittii, Bacillus funiculatus, B. subtilis, Filifactor villosus, Lactobacillus equi, L. malferment, L. quasseri and Pseudomonas orientalis. Lactobacillus species predominated over the other bacteria genera encountered. All the seasonings contained variable high to low contents of Fe, Na, K, Ca and Mg. The heavy metals occurred in low or trace amounts namely Cu, Zn, Pb, Cr, Ni, Co, Ar and Hg. Benny shrimp powder contained high concentration of K (4240mg/l) and Na (424.20mg/l), while Onga chicken seasoning contained high Na (13,700mg/l); Remie chicken seasoning powder contained 104.82mg/l of Fe. Aflatoxins (B1, B2, G1 and G2) and ochratoxin A were not detected in all the test samples but there was the presence of Monosodium Glutamate. Gamma irradiation dose of 5-10KGy decontaminated the samples