· Most bacteria prefer pH around 7 (neutral)
· When foods have a lower pH the yeasts and moulds are problematic
· The limit of growth for Clostridium botulinum type E is 4.5,this is relevant in canning
· Some strains of salmonella and Staphylococcus aureus may be capable of growth at pH as low as 3.8
(Salmonella has been involved in food poisoning outbreak with apple juice)
· E. coli is acid tolerant and consequently has been the cause of foodborne outbreaks due to consuming acidic foods such as apple juice and cider
· Note the alkaline end of the pH scale is used for cleaning and disinfection e.g. caustic soda
· Alkalis are unpalatable