Influence of forced-air precooling time on the changes in quality attributes and consumer acceptance of Musa AAA Berangan

A good temperature management, such as precooling and cold storage, can delay deterioration of fresh produce. In this study, different forced-air precooling times were applied on Musa AAA Berangan to investigate the influence of forced-air precooling time on the changes of quality attributes and consumer acceptance. The banana was subjected to forced-air precooling treatment (5 ± 1°C) for 0, 14, 50, and 120 min and then stored in a cold room (13 ± 1°C) for 2 weeks. Then, all the fruits were transferred to a ripening room (25 ± 2°C) and initiated to ripen with ethylene gas. Quality attributes analyses and sensory evaluations were conducted when the fruits reached maturity index 5. Quality parameters, such as soluble solids concentration, titratable acidity, pulp firmness, and peel colour, showed no significant differences when fruits were precooled at different times. Blackening of peel as a result of chilling injury occurred in fruits treated with forced-air precooling for 50 and 120 min. This blackening significantly influenced consumer acceptance, although it did not affect the pulp colour and taste

Isolation and antibiotic susceptibility profile of Vibrio cholerae isolated from catfish (Pangasius hypothalmus)

To date, cholera has cycle the world seven times through the seven pandemic cycles that has affected tens of millions of people. The objective of this study was to determine the presence and density as well as the antibiotic resistance profile of Vibrio cholerae isolated from catfish (Pangasius hypohthalamus). From the combination of the Most Probable Number-Polymerase Chain Reaction-plating on TCBS agar methods, V. cholerae was detected in 32 samples and V. cholerae O139 was detected in 7 samples, with a density ranging between <3.0 to 75.0 MPN/g and <3.0 to 9.3 MPN/g respectively. The results obtained in this study indicate that V. cholerae will continue to be a major healthcare burden, as the pathogen can be transferred from the aquatic environment to the catfish and the consumption of catfish by humans will present a route of exposure to V. cholerae. Proliferation of antibiotic and multiantibiotic resistant bacteria is a public health threat worldwide. Results of antimicrobial susceptibility investigation of V. cholerae isolates collected from catfish reported in this study will establish an important baseline data. All the V. cholerae isolates were multiantibiotic resistant towards the ten antibiotics tested, including 6 isolates that were resistant to all ten antibiotics and 38 antibiotic resistance patterns. The MAR index values of 0.2 to 1.0 indicate that the isolates were exposed to high risk sources in the environment. Taken together, the information on the prevalence and antibiotic resistance of V. cholerae indicate that catfish consumption presents a potential risk to human health and highlight the need for ongoing epidemiological and antimicrobial resistance surveillance

Antimicrobial resistance of Listeria monocytogenes and Salmonella Enteritidis isolated from vegetable farms and retail markets in Malaysia

Listeriosis and salmonellosis are the major foodborne illnesses worldwide. Over the last decade, increasing reports about the antibiotic resistance of Listeria monocytogenes and Salmonella from diverse sources have prompted public health concerns, especially in developing countries with over reliance or misuse of antibiotic drugs in the treatment of humans and animals. In this study, antibiotic susceptibility profiles of 58 L. monocytogenes and 12 Salmonella Enteritidis strains from vegetable farms and retail markets in Malaysia were tested by the standard disk diffusion method. Listeria monocytogenes isolates were found to exhibit 100% resistance to penicillin G. Also, high resistance patterns were observed for meropenem (70.7%) and rifampicin (41.4%). The multiple antibiotic resistance (MAR) index of L. monocytogenes isolates ranged from 0.11 to 0.56. Besides, the antibiogram results revealed that multidrug-resistant (MDR) S. Enteritidis were detected and all the S. Enteritidis isolates demonstrated resistance to at least four antibiotics. Ampicillin, amoxicillin, and trimethoprim failed to inhibit all the S. Enteritidis strains. Salmonella Enteritidis isolates also displayed high resistance to nalidixic acid (75.0%), trimethoprim-sulfamethoxazole (75.0%), and chloramphenicol (66.7%). Findings in this study indicated that vegetables could be potential sources of multidrug resistance of L. monocytogenes and S. Enteritidis, which can be a serious issue and a major concern for public health. Thus, there is a great need for surveillance programs in Malaysia to continuously monitor the antibiotic resistance profiles of important pathogens

Quantitative detection and characterization of Shiga toxin-producing Escherichia coli O157 and non-O157 in raw vegetables by MPN-PCR in Malaysia

Foodborne diseases are mainly caused by bacterial contamination which can lead to severe diarrhea. This study aimed to detect the presence of Shiga toxin-Producing Escherichia coli O157, Escherichia coli non-O157 and virulence gene in raw vegetables. The samples were purchased from wet market and hypermarket in Selangor. The detections were carried out by using the combination methods of Most Probable Number-Polymerase Chain Reaction (MPN- PCR). A total of 37(18.5%) samples were found to be contaminated by STEC. Out of these 37 isolates, four (10.8%) of the isolates were E. coli O157 while 33(89.2%) were E. coli non- O157. However, there was no E. coli O157:H7 detected in all the samples. The occurrence of Shiga toxin-Producing E. coli in edible raw vegetables samples suggests the importance of this pathogen in vegetables. Therefore, more studies are required to remove this pathogen from vegetables

Risk of Escherichia coli O157:H7 transmission linked to the consumption of raw milk

E. coli O157:H7 is associated with life threatening diseases such as hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Raw milk is considered a high risk food as it is highly nutritious and serves as an ideal medium for bacterial growth. The aim of this study was to investigate the prevalence of E. coli O157:H7 in raw cow, goat and buffalo milk samples. MPN-PCR method targeting the major virulence rfbE gene and fliCH 7 gene of E. coli O157:H7 was used. Total of 177 raw milk samples were collected from local dairy farms in the state of Selangor, Malaysia. The highest prevalence of E. coli O157:H7 was found in raw cow milk (8.75%) followed by raw goat milk (7.32%) and raw buffalo milk (1.79%). The estimated quantity of E. coli O157:H7 in raw cow, goat and buffalo milk ranged from <30 MPN/g to 120 MPN/g. In raw cow and goat milk samples examined contain E. coli O157:H7 microbial load ranged from 30 to 120 MPN/g and 30 to 36 MPN/g, respectively. E. coli O157:H7 microbial load in buffalo milk samples was found to be the lowest, only 30 MPN/g. Results of this research provide useful information on biosafety of E. coli O157:H7 in raw milk marketed in Malaysia

Detection of Klebsiella pneumoniae in raw vegetables using most probable number-polymerase chain reaction (MPN-PCR)

Klebsiella pneumoniae (K. pneumoniae) is one of the most important members of Klebsiella genus in Enterobacteriacae family, which is responsible for pneumonia (the destructive lung inflammation disease). Vegetables are known as source of contamination with K. pneumonia. Raw vegetables are usually consumed in salads and other dishes. The aim of this study was to investigate the occurrence of K. pneumoniae in raw vegetables marketed in Malaysia. Two hundred commonly used salad vegetables (lettuces, parsley, cucumber, tomato and carrot) from hypermarkets and wet markets were investigated for presence of K. pneumoniae using Most Probable Number-Polymerase Chain Reaction (MPN-PCR). K. pneumoniae was found to be significantly more frequent (100%) and (82.5%) in lettuce and cucumbers, respectively. K. pneumoniae contamination was lowest in carrot samples (30%). All samples were contaminated with K. pneumoniae ranging from <3 to 1100 MPN/g. Results showed the high health risk associated with consumption of raw vegetables

Risk assessment of acquiring listeriosis from consumption of chicken offal in Selangor, Malaysia

Listeria monocytogenes (L. monocytogenes) is an important foodborne pathogen which can cause foodborne listeriosis with high mortality rates especially in susceptible population groups such as pregnant women, elderly and immunocompromised individuals. The biosafety level of L. monocytogenes in chicken offal has becomes a great concern as chicken offal is a cheap source of protein and it is often served as side dishes in South East Asian countries. In Malaysia, the consumption of chicken offal has almost doubled from 5 g per capita per day in the early 1980s to 9 g per capita per day in 2009. In this study, risk assessment was conducted to estimate the risk of acquiring listeriosis from consumption of chicken offal in Malaysia. A microbial survey on the prevalence and concentration of L. monocytogenes in chicken offal were carried out in Selangor, Malaysia over a one-year period (November 2010 to October 2011). It was assumed that there were no seasonal changes in the prevalence and consumption pattern all year round. Assuming that 5.6 million people in Selangor, Malaysia consume a single serving (125 g) of chicken offal per week, it is estimated that in a year there could be 0.61 cases and 1.98 × 10-4 cases of listeriosis per 100,000 population of pregnant woman and immunocompromised individual, respectively. However, the potential for getting listeriosis among the healthy population was very low, only 1.39 × 10-8 cases per 100,000 population. This study demonstrated risk assessment model not only used as a tool to estimate the risk of acquiring illness but it can influence public health surveillance and providing data in setting appropriate level of protection

Simulation of decontamination and transmission of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes during handling of raw vegetables in domestic kitchens

Epidemiological data indicates that a large number of foodborne illnesses are attributed to cross-contamination during food preparation in the domestic kitchen. The objectives of this study were to evaluate the efficiency of household washing practices in removing Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis on artificially contaminated lettuce and to determine the transfer rate of these three foodborne pathogens from contaminated lettuce to wash water, tomato, cabbage, and cutting boards during washing and cutting processes. Washing under the running tap water with scrubbing for 60 s was the most effective method in reducing pathogen populations by 1.86 to 2.60 log10 CFU/g. Also, final rinsing and scrubbing practices were found to enhance the efficiency of washing treatment. In this study, the transfer rates of S. Enteritidis, E. coli O157:H7, and L. monocytogenes from cutting board to cabbage and tomato via cutting process (17.5 to 31.7%) were higher (P<0.05) than from wash water to cabbage and tomato (0.8 to 23.0%) during washing treatment. Overall, our findings suggest that wash water and cutting board can be potential vehicles in the dissemination of foodborne pathogens. Therefore, there is a need to promote consumer awareness for proper handling practices in the kitchen to minimise the risk of foodborne infection

Simulation of decontamination and transmission of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes during handling of raw vegetables in domestic kitchens

Epidemiological data indicates that a large number of foodborne illnesses are attributed to cross-contamination during food preparation in the domestic kitchen. The objectives of this study were to evaluate the efficiency of household washing practices in removing Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis on artificially contaminated lettuce and to determine the transfer rate of these three foodborne pathogens from contaminated lettuce to wash water, tomato, cabbage, and cutting boards during washing and cutting processes. Washing under the running tap water with scrubbing for 60 s was the most effective method in reducing pathogen populations by 1.86–2.60 log10 CFU/g. Also, final rinsing and scrubbing practices were found to enhance the efficiency of washing treatment. In this study, the transfer rates of S. Enteritidis, E. coli O157:H7, and L. monocytogenes from cutting board to cabbage and tomato via cutting process (17.5–31.7%) were higher (P < 0.05) than from wash water to cabbage and tomato (0.8–23.0%) during washing treatment. Overall, our findings suggest that wash water and cutting board can be potential vehicles in the dissemination of foodborne pathogens. Therefore, there is a need to promote consumer awareness for proper handling practices in the kitchen to minimise the risk of foodborne infection

Quantification and antibiotic susceptibility of Salmonella spp., Salmonella enteritidis and Salmonella typhimurium in raw vegetables (ulam)

Salmonella has been reported to be presence both in raw and processed foods worldwide. In this study, the prevalence, quantification and antibiotic susceptibility of Salmonella isolated from raw vegetables or locally known as ulam such as asiatic pennywort (Centella asiatica (L) Urb), water dropwort (Oenanthe javanica (Blume) DC), long bean (Vigna sinensis EndL), and winged bean (Psophocarpus tetragonolobus (L) DC) obtained from retail markets in Selangor, Malaysia were carried out. From 96 samples tested, the overall prevalence of Salmonella spp. was 97.9%, Salmonella Enteritidis was 54.2% and Salmonella Typhimurium was 82.3% respectively. Samples were contaminated with Salmonella ranging from <3 to 2400 MPN/g. Salmonella Enteritidis and Salmonella Typhimurium isolates obtained from the raw vegetables (ulam) were found to exhibit high resistance against ampicillin (100%), erythromycin (100%), amoxicillin/clavunic acid (81.3%), cephalothin (75%), streptomycin (50%) and ciprofloxacin (50%). All Salmonella isolates showed multi drug resistant (MDR) profile with each isolate being resistant to 3 or more antibiotics. The multiple antibiotic resistance (MAR) index of Salmonella isolates ranged from 0.27 to 0.55 for Salmonella Enteritidis and 0.27 to 0.82 for Salmonella Typhimurium. The presence of Salmonella on raw vegetables (ulam) and high antibiotic resistance isolates indicated that raw vegetables could be contaminated and thus imposes possible health risk to local consumers