Browsing by Author "Nanteza, Hasifa"

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    The Occurrence of Bacillus Cereus in White Pepper from Bogor, Indonesia
    (IOP Publishing, 2022) Nanteza, Hasifa; Dewanti-Hariyadi, Ratih; Nurjanah, Siti
    White pepper (Piper nigrum L.) is a spice with earthy heat and an intense floral aroma widely produced and consumed in Asia. In Indonesia, it is commonly used to flavor dishes that require a spicy taste. However, white pepper can be contaminated by pathogenic microorganisms, such as Bacillus cereus, an endospore-forming bacterium widely grounded in soil and dust. The bacterium causes emetic and diarrheal syndromes and has been implicated in various foodborne disease outbreaks in different parts of the world. Currently, data pertaining to the occurrence of Bacillus cereus in white pepper in Indonesia is not available. This study aimed to isolate and assess the occurrence of Bacillus cereus in white pepper obtained from markets in Bogor, Indonesia. The study consisted of sample collection and preparation, isolation and enumeration of Bacillus cereus using Mannitol egg yolk polymyxin (MYP) agar, and confirmation by biochemical tests and Polymerase Chain Reaction to detect the gene encoding for16S rRNA. Of the 20 samples analyzed, 18 of them (90%) were contaminated with presumptive Bacillus cereus, and the highest concentration was 5.77 log10 cfu/g. The high counts of Bacillus cereus were probably attributed to the postharvest processing operations that the spice encountered. All the 15 tested isolates showed a clear band at the expected length of around 1686bp after being separated from PCR products on ethidium bromide-stained 2% agarose gel. This result confirmed the existence of Bacillus cereus in white pepper samples.
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    Phylogenic identification of toxigenic Bacillus cereus in chili and white pepper from Bogor area, Indonesia
    (Fascicle VI-Food Technology, 2022) Nanteza, Hasifa; Dewanti-Hariyadi, Ratih; Nurjanah, Siti
    This study aimed to compare the occurrence and level of Bacillus cereus sensu stricto (B. cereus) in chili, and in previously isolated white pepper from traditional and supermarkets around Bogor, to determine the phylogenetic relationship between the obtained isolates based on their 16S rDNA gene, and to determine their potential toxicity based on ces and nheA genes using Polymerase Chain Reaction. The highest presumptive B. cereus level in samples from traditional and supermarkets was 5.95×105 and 2.6×105 CFU/g respectively. The difference in B. cereus levels between the two market types was not significant. Ten presumptive isolates from chili and 10 from white pepper from our previous study were sequenced, subjected to BLAST analysis, and 13 were confirmed as B. cereus sensu lato. The sequences were phylogenetically analysed and tested for the possession of nheA and ces toxigenic genes. Based on the phylogenetic tree established, 12 of 13 isolates were related to B. cereus, sharing >98% similarity with reference strains. All 12 (100%) isolates owned the nheA gene; none of them possessed the ces gene. Absence of ces gene lessens the danger for emesis from these spices, nonetheless, the 100% presence of nheA gene presents a potential risk for B. cereus diarrheal syndrome.