Validation and verification of LAMP, ISO, and VIDAS UP methods for detection of Escherichia coli O157:H7 in different food matrices

Escherichia coli O157:H7 is one of the most important food-borne pathogens to threaten public health. Cultural methods are used as a gold standard while they are laborious and time-consuming. Loop-mediated isothermal amplification (LAMP) method is an alternative method that became widely used for the detection of food-borne pathogens. The aim of this study was to evaluate the specificity and sensitivity of LAMP method for detection of E. coli O157:H7, also to compare detection performances with VIDAS UP and ISO (International Organization for Standardization) methods in different food matrices (beef meat, minced lamb meat, milk, cheese, apple puree, and soybean sprouts). E. coli O157:H7 were spiked in three different levels (high 4.58; medium 2.32; low 0.30 log10 CFU/g-ml) to food matrices. Although there were no significant differences in terms of the specificity and sensitivity values among the three methods (p ≥.05), it was determined that the highest specificity and sensitivity values obtained from the LAMP method. Sensitivity and specificity values of LAMP method were found as 0.997 and 0.988, for the ISO method were 0.989 and 0.971, and for the VIDAS UP method were 0.980 and 0.963, respectively. In milk samples, sensitivity and specificity values of the VIDAS UP method were significantly lower than LAMP and ISO methods (p <.05). However, there were no significant differences found for the other food matrices among the three methods (p >.05). It can be summarized from this study that specificity and sensitivity values of the LAMP method are equal or higher and less time-consuming than ISO and VIDAS UP methods. In conclusion, using a simple, fast, and inexpensive detection method, such as LAMP, especially in endemic regions or in an outbreak to control spreading of pathogens, is very important for public health. © 201

Characterization of Salmonella isolated from organically reared poultry located in the same longitude with three distinct seasonal characteristics

This study is designed to determine Salmonella prevalence in organic poultry farms and slaughterhouse in three different regions with distinct seasonal characteristics. Salmonella strains were isolated from organic reared poultry farm environment (water, feed, and feces) and poultry meat samples (neck skin and breast meat). Antibiotic resistance and 16S rRNA profiles were demonstrated with alignment scores. Salmonella spp. prevalences according to regions were, 51 of 200 (25.50%) samples taken from Region A, 77 of 200 (38.50%) samples taken from Region B, 105 of 200 (52.50%) samples taken from Region C. Serotyping of the strains revealed that S. Typhimurium and S. Enteritidis are the most dormant strains among all strains. Antibiotic susceptibility of the strains revealed that major resistance against ampicillin. This study is held for an awareness rising about the possible impact of seasonality related with food borne pathogens prevalence. Practical applications: Poultry meat and meat products account for approximately one-third of all Salmonella infections in humans. The relation between environmental temperature and foodborne pathogens is a complex matter, which has not been investigated widely and is hard to predict. The data obtained in this study indicate a significant high prevalence in warm region, which may be evaluated as a possible key for environmental temperature effect on foodborne pathogens distribution in organically reared poultry. In addition, this study provides important information to show the sources of contamination steps ranging from farm to fork in organically reared poultry. © 2018 Wiley Periodicals, Inc