Microwave heating technology is widely used in food catering and domestic households. Nonuniformity of microwave temperature distribution causes the formation of hot and cold spots in heated product has led to the survival of foodborne pathogens which may later cause food borne diseases. It is the aim of this study to determine the effect of different microwave heating on the microbiological quality of microwavable frozen chicken curries. Nine commercialised frozen chicken curries were thawed overnight in the chiller (< 4°C) and exposed to different microwave power levels and times (270 W at 60 s; 950 W at 150 s and 300 s). 25 g of chicken curry were homogenised, serial diluted and enumerated aseptically. Total Aerobic Count (TAC), Total Coliform Count (TCC), Escherichia coli count and Salmonella count were carried out and no microorganisms were detected. Enterobacteriaceae were found in the food samples after enrichment process. Polymerase Chain Reaction (PCR) amplification and 16S ribosomal ribonucleic acid (rRNA) sequencing were carried out. Results of 16S rRNA sequence analysis indicated that two gram-negative isolates after enrichment were identified as Klebsiella pneumoniae.
Chlorella is one of the common microalgae found in a wide range of habitats, including Antarctica. Chlorella UMACC 234 is an interesting isolate in the collection of Antarctic microalgae in the University of Malaya algae culture collection (UMACC) as it grows well at temperatures much higher than the ambience. The alga was isolated from snow samples collected from Casey, Antarctica. This study investigates the influence of nitrogen source on the growth, biochemical composition and fatty acid profile of Chlorella UMACC 234. The cultures were grown in Bold’s Basal Medium with 3.0 mM NaNO3, NH4Cl or urea. The cultures grown on NaNO3 attained the highest specific growth rate (μ = 0.43 day–1) while the specific growth rates of those grown on NH4Cl and urea were not significantly different (p > 0.05). The urea-grown cells produced the highest amounts of lipids (25.7% dry weight) and proteins (52.5% dry weight) compared to those grown on other nitrogen sources. The cell numbers attained by the cultures grown at NaNO3 levels between 0.3 and 3.0 mM were similar but decreased markedly at 9.0 mM NaNO3. The fatty acids of Chlorella UMACC 234 were dominated by saturated fatty acids, especially 16:0 and 18:0. The percentage of polyunsaturated fatty acids was very low, especially in cells grown on urea (0.9% total fatty acids). Characterisation of the growth and biochemical composition of this Antarctic Chlorella is important to our studies on the relationship of Chorella isolates from tropical, temperate and polar regions, especially in terms of phylogeny and stress adaptation.
Cross contamination is one of the most important contributing factors in foodborne illness
originating in household environments. The objective of this research was to determine the
transfer between naturally contaminated chicken liver and leg to cutting board, hand glove,
knife and cucumber, during slicing. The microorganism tested was Campylobacter jejuni and
the results showed that the pathogen transferred to all utensils, at different transfer rate, despite
the low level of the naturally contaminating pathogen. With unknown concentration bacteria in
the naturally contaminated samples, a proportion of the utensils were still contaminated with C.
jejuni and not surprisingly, when the sample were contaminated with higher concentrations of
the pathogen, a higher proportion of the utensils had detectable C. jejuni cells present, though
in many cases cross contamination seems to be a random event. Transfer of the naturally
contaminating C. jejuni from the chicken liver and leg to the utensils were