Ultra high temperature (UHT) treated milk products and formula milk are known to be
frequently contaminated with Bacillus cereus. Presence of B. cereus in these milk products is
of particular concern considering the majority of consumers are infants and children. Possible
sources of contamination are contaminated raw milk, cross-contamination during processing,
under-processing and mishandling of milk products. This study was conducted to detect the
presence of B. cereus in both formula milk (n=12) and UHT milk (n=20) sold in selected retail
markets. The approach consisted of enumerating by MPN/g followed by PCR assay aimed
at detecting gyrB gene in B. cereus, that encode for the subunit B protein of DNA gyrase
(topoisomerase type II). Contamination level of B. cereus in both types of samples examined
ranged from < 3 to > 1100 MPN/g. The contamination level of B. cereus was found to be
highest in full cream UHT milk (> 1100 MPN/g) and formula milk (> 1100 MPN/g). The PCR
analysis showed that 41.7% (5/12) formula milk and 30% (6/20) UHT milk samples were
detected with B. cereus, respectively. This is the first report of such study demonstrating the
presence of B. cereus in formula milk from Malaysia. Therefore, constant surveillance of these
milk products would reduce the potential risk of B. cereus-linked outbreaks.
The revolution of agriculture through biotechnology have produced large-scale of genetically
modified crops which brought up a controversy on the safety usage of genetically modified
organisms (GMOs). It has been implemented globally that all GMO products and its derived
ingredients should have regulations on the usage and labelling. Thus, it is necessary to develop
methods that allow rapid screening of GMO products to comply with the regulations. This
study employed a reliable and flexible multiplex polymerase chain reaction (PCR) method for
the rapid detection of transgenic elements in genetically modified soy and maize along with
the soybean LECTIN gene and maize ZEIN gene respectively. The selected four common
transgenic elements were 35S promoter (35S); Agrobacterium tumefaciens nopaline synthase
terminator (NOS); 5-enolypyruvylshikimate-3-phosphate synthase (epsps) gene; and Cry1Ab
delta-endotoxin (cry1Ab) gene. Optimization of the multiplex PCR methods were carried out
by using 1% Roundup ReadyTM Soybean (RRS) as the certified reference material for soybean
that produced fourplex PCR method detecting 35S promoter, NOS terminator, epsps gene and
soybean LECTIN gene and by using 1% MON810 as the certified reference material for maize
that produced triplex PCR method detecting 35S promoter, cry1Ab gene and maize ZEIN gene
prior to screening of the GMO traits in various food products and animal feeds. 1/9 (11.1%) of
the animal feed contained maize and 1/15 (6.7%) of the soybean food products showed positive
results for the detection of GMO transgenic gene. None of the maize food products showed
positive results for GMO transgenic gene. In total, approximately 4% of the food products
and animal feed were positive as GMO. This indicated GMOs have not widely entered the
food chain. However, it is necessary to have an appropriate screening method due to GMOs’
unknown potential risk to humans and to animals. This rapid screening method will provide
leverage in terms of being economically wise, time saving and reliable.
Vibrio cholerae still represents a significant threat to human health worldwide despite the advances in hygiene, consumer knowledge, food treatment and food processing. In Malaysia, statistics in year 2009 have shown that among the food and water borne diseases, food poisoning has the highest incidence rate of 36.17 per 100,000 populations and with a mortality rate of 0.01 per 100,000 populations. In this study, 22 seafood samples comprising of fish, squid, crustacean and mollusks purchased from wet market and supermarket were analyzed. The Most Probable Number (MPN) and real time PCR was used to enumerate the Vibrio cholerae in seafood sample. The results showed that MPN-real time PCR of the samples from wet market had a maximum of >1100 MPN/g compare to 93 MPN/g enumerated from the MPN plate. The MPN-real time PCR in the samples from supermarket indicated 290 MPN/g as compared to 240 MPN/g enumerated from the MPN plate. The standard curves showed that there was a good linear correlation between the Ct values. The minimum level of detection of Vibrio cholerae standard DNA at targeted gene was 3 x 10-5 ng/μl.
Salmonella has caused foodborne illnesses globally and it has been a rising threat on fresh produce. The objective of this study was to determine the prevalence and concentration of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in freshly prepared fruit juice sold at hawker stalls. Analysis was conducted by employing most probable number-polymerase chain reaction (MPN-PCR). A total of 50 freshly prepared fruit juices were examined and the prevalence of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in the fruit juices were 34%, 20% and 10%, respectively, with an estimated microbial load varying from 0 to 42 MPN/g. Of the five different fruits, carrot juice had the highest prevalence of Salmonella spp. (60%) and Salmonella Typhi (40%). However, Salmonella Typhimurium was detected in apple (30%), orange (10%) and starfruit juice (10%). Factors contributing to the presence of Salmonella were cross-contamination and poor sanitation practice. Besides, negligence on temperature and storage time also led to the growth of Salmonella. Proper monitoring and risk assessment are needed in order to establish control measures to ensure the quality and safety of fruit juices in Malaysia.
Nowadays, the incidence rate of foodborne disease has increased and become one of the global burdens affecting all individual ages in South East Asia region. Foodborne disease is responsible for mortality and morbidity worldwide thus affecting socio-economic and quality of life. Major causes of foodborne hazards diseases include diarrheal and invasive infectious disease agent, helminthes and chemicals. However, in developing countries, data and record is insufficient with poor surveillance systems leading to incomplete information on the real burden of foodborne disease. The introduction of Actor Network Theory (ANT) as tools for assessing and analyzing the food safety issues has drawn attention from various researcher as it is proven to be able to point out and identify the human and non human actors which is directly and contingently involved. The interaction between the actors such as a worker in an organization, student in school, and peoples in public provide information that can be used to minimize the risk of foodborne disease. The ultimate use of ANT is it helps the researcher to draw a framework of the source of contamination, agent responsible, factors involved, and idea to control the spread.
Salmonella remains to be a major foodborne pathogen for animals and humans and is the
leading cause of foodborne infections and outbreaks in various countries. Salmonella Enteritidis
is one of the most frequently isolated serotypes in poultry and poultry products from human
food poisoning cases. It can cause mild to acute gastroenterititis as well as other common
food poisoning symptoms when infection takes place in human. Nucleic acid amplification
technologies such as Polymerase Chain Reaction (PCR) is a tool that is rapid and sensitive
for detection of bacterial pathogen. We report the successful detection of S. Enteritidis by
PCR in raw chicken meat artificially-contaminated with serial concentration of S. Enteritidis
using crude DNA extracts as DNA template. PCR primers, ENT-F and ENT-R targeted on sdfI
gene were used to amplify DNA region unique to S. Enteritidis with crude DNA extract of the
samples, yielded product with the size of 303 bp. These primers were specific to S. Enteritidis
when tested by in-silico simulation against genome database of targeted bacterial species and
confirmed in PCR as amplification bands were observed with S. Typhimurium, S. Polarum and
S. Gallinarum. The established PCR can detect as few as 9.4 X 101
CFU/ml of inoculated S.
Enteritidis concentration and proved that pre-enrichment effect have significant effect on PCR
detection by increasing 1000-fold of the sensitivity limit compared to the non pre-enriched
samples. The PCR technique indicated that it can be successfully coupled with pre-enrichment
step to offer advantage in routine screening and surveillance of bacterial contamination in food
samples.
Application of surface plasmon resonance (SPR) biosensor in detection of genetically modified organism (GMO) is demonstrated. A total of four biotinylated probes namely Tnosb, P35Sb, LECb and TSQb were successfully immobilized onto the SA chip. Results analysis indicated that the SPR system with the sensor chip immobilized with the Tnosb, P35Sb, LECb and TSQb biotinylated probes potentially detect complementary standard fragments as low as 1 nM. Biospecific interaction analysis (BIA), employing surface plasmon resonance (SPR) and biosensor technologies provide easy, rapid and automatable approach in detection of GMOs. Short assay times, label free DNA hybridization reaction and no toxic compounds are required, i.e. ethidium bromide, and the reusability of the sensor surface are some of the factors that contribute to the general advantages of the surface plasmon resonance (SPR) biosensor system in detection of GMOs.
Since the introduction of the molecularly imprinting technology (MIT) in 1970s, it becomes an emerging technology with the potential for wide-ranging applications in food manufacturing, processing, analysis and quality control. It has been successfully applied in food microbiology, removal of undesirable components
from food matrices, detection of hazardous residues or pollutants and sensors. Molecularly imprinted solid-phase extraction (MISPE) is the most common application so far. The review describes the methods of making the molecularly imprinted polymer systems, the application of the technology in food safety issues and the remaining challenges.