PA BROTH

Acidic media are not completely suitable for counting yeasts and moulds in foods since yeast cells, stressed by heat do Availability of clean water for bathing, drinking and cooking is critical for modern civilization. Different pathogens can be transmitted through water contaminated by faeces and other sources leading to diseases such as diarrhea, typhoid, cholera etc. Different strategies have been developed for bacteriological examination of water. Weiss and Hunter proposed a simplified procedure for the bacteriological examination of treated water. Later on the PA (Presence Absence) test was developed as a simplified version of the test based on the principle that coliforms and other bacterial indicators of pollution should not be found in 100 ml samples of treated water. Other aspects of PA test were studied by Clark et al. PA Broth has been included as a tentative standard in the Standard Methods for the Examination of Water and Wastewater justified on the theory that a 100 ml sample of drinking water should not contain any coliform. The Presence Absence (PA) test for the coliform group is a simple modification of the multiple-tube procedures and provides a qualitative estimate of coliforms

for detection of presence and absence of coliform bacteria in water