Comparison between laser light-scattering method and traditional methods in identifying some Campylobacter and Staphylococcus isolates from foods

Species of the genus Campylobacterare recognized as the main cause of foodborne disease in both developing and developed countries. They are main causative of diarrhea and gastroenteritis worldwide. Staphylococcus bacteria especially S. aureus are responsible of food poisoning due to their ability to produce enterotoxins. Traditional methods which are used to identify bacteria are time-consuming and labor intensive and very expensive. Thirteen isolates of Campylobacter and twenty-two isolates of Staphylococcus were isolated from a variety of foods. Traditional methods based on biochemical tests were used for identification in addition to laser light-scattering technique to discriminate isolates. Laser light-scattering technique showed the ability to distinguish all isolate in high accuracy, rapid and low costs manner, thus it may represent a potential alternative to traditional methods to identify these bacteria. So it is a very important issue to find new alternative methods characterized by high accuracy, low costs and rapidity in results achievement, to replace traditional methods, thus laser light-scattering may be a possible alternative

Comparison between FTIR-ATR technique and traditional methods in discrimination of Bacillus isolates from some foods

Forty-five Bacillus isolates were obtained from different foods (spices, grains, dried milk), the isolates were identified using traditional method from Bergey's manual based on morphological tests (gram staining, spores staining), physiological tests (optimum growth temperature, pH, NaCl concentration) and biochemical tests (Voges-Proskauer, gelatin hydrolysis, esculin hydrolysis, β- Galactosidase test, Lysine decarboxylase and Ornithine decarboxylase, production of acid from different sugars). Bacterial suspensions were prepared from the isolates and FTIR spectrums were obtained using ATR unit, which consists of ZnSe prism, by scanning at the range of 4000-400 cm-1. Results revealed that the isolates represented 5 species of Bacillus (B. pumilus, B. subtilis, B. lentus, B. megaterium, B. cereus) and the potential of Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) method as a reliable method for discrimination among Bacillus isolates, which is accurate, rapid, easy to apply and cheap.