Microbiological quality of fresh vegetables and fruits sold in Singapore

The aim of this study was to characterise the microbiological quality of selected common fresh vegetables and fruits commercially sold in Singapore in order to provide insight into any potential health hazards associated with consumption of these commodities. A total of 125 samples, collected from major supermarkets and local markets, were tested for aerobic mesophilic and psychrotrophic bacterial counts. One hundred samples were analysed for enumeration of yeasts and moulds, enumeration of coliforms and detection of Escherichia coli O157:H7 and Salmonella spp. Aerobic mesophilic counts ranged from 1.6 to 9.1 log cfu/g, with the lowest and the highest counts recorded for orange and bean sprouts, respectively. The highest level of coliforms was found in bean sprouts and fresh-cut salad, with 50% of samples containing more than 5 log cfu/g. Like coliform counts, the highest counts of yeasts and moulds were obtained in bean sprouts and fresh-cut salads. Fresh-cut salads also had the highest mean psychrotrophic plate count of 4.9 log cfu/g. Although no E. coli O157:H7 or Salmonella spp. was detected in the fruits and vegetables analysed in this study, high bacterial counts, especially in bean sprouts and fresh-cut salad, imply that effective control measures should be implemented to improve the microbiological quality of fresh produce sold in Singapore.     

Lysophosphatidylcholine acyltransferases activity during experimental cholelithiasis

The accumulation of (1-palmitoyl)lysophosphatidylcholine, lysolecithin, in gallbladder bile was observed during the first week of cholesterol-induced experimentals cholelithiasis using the prairie dog model for cholesterol gallstone formation. Gallbladder fluid transport function decreased as bile lysolecithin concentration increased. These observations suggest that lysolecithin play an important, early role in the etiology of gallstone disease. Furthermore, the relative activities of hepatic and gallbladder mucosa lysophosphatidylcholine acyltransferase and acylcoenzyme A hydrolases may be responsible for the turnover of gallbladder bile lysolecithin.