Effect of Water Activity, pH, and Lactic Acid Bacteria to Inhibit Escherichia coli during Chihuahua Cheese Manufacture.

This study aimed to evaluate the effectiveness of pH control, water activity (Aw), and the addition of lactic acid bacteria (LAB) on the proliferation of Escherichia coli in the curd during the manufacturing of Chihuahua cheese. Milk proved to be an excellent culture medium for E. coli, allowing it to develop at concentrations up to 109 cfu/g. However, the presence of LAB, the pH control, Aw, and especially the use of the Cheddarization process during the Chihuahua cheese production proved to be important obstacles that inhibited the proliferation of E. coli under the conditions studied. Moreover, reducing the water activity of the curd as quickly as possible is presented as the most powerful tool to inhibit the development of E. coli during the Chihuahua cheese-making process.

Comparison of Efficiency and Image Quality of Photostimulable Phosphor Plate and Charge-Coupled Device Receptors in Dental Radiography.

The photostimulable phosphor (PSP) plate and charge-coupled device (CCD) are receptors commonly used for intraoral radiography in U.S. dental schools. However, it is unclear which receptor is more beneficial for radiology education and patient care in an academic setting. The aim of this study was to compare the time efficiency, image quality, and operator performance for student-operated PSP plate and CCD receptors. At one U.S. dental school in 2018, 20 dental hygiene and dental students (n=10 each) were recruited as operators. They each exposed anterior and posterior periapical and bitewing radiographs on dental radiograph teaching and training replica using the PSP plate and CCD as receptors. The time taken to expose the radiographs was recorded. Image sharpness/definition, brightness/contrast, and technical errors, including placement, angulation, and cone cut errors, were evaluated on a three-point scale with 0=non-diagnostic, 1=diagnostic acceptable with minor errors, and 2=perfect diagnostic quality. The results showed that it was generally faster for the students to expose intraoral radiographs with CCDs than with PSP plates, although the difference was not significant (p>0.05). Image quality and technical accuracy, especially angulation, were significantly superior for PSP relative to CCD (p<0.05). This study found that PSP imaging was of higher quality and accuracy than CCD, whereas CCD was more efficient. Dental and dental hygiene students would benefit from being trained on both receptors to be able to adapt to a diversified workplace.