9/18/2016 Characteristics of C.botulinum Characteristics of C.botulinum pH Salt and water activity ·Minimum pH Sodium chloride acts by decreasing Group I-pH4.6 the water activity Group II-pH5 Concentration of salt in the water Most fruits and vegetables are acidic phase called brine concentration is enough to inhibit C.botulinum critical Other growth conditions affect the NaCl,KCl,glucose and sucrose give pH growth response similar effects Molds and yeasts may raise the pH so Acidity and preservatives may also that C.botulinum growth is allowed affect the water activity Characteristics of C.botulinum UltraZapXtendaPak Carbon dioxide is used in Active pad contains modified-atmosphere Oxygen and redox potential additives that pro ce Amount of oxygen is not the critical variable carbon dioxide,which has packaging Oxygen-reduction potential is the critical variable bacteriostatic properties Strict anaerobes are generally active at negative Moisture from the packaged protein is redox values absorbed by the Most foods are low enough to permit growth UltraZapXtendaPak Little data-difficult to measure cellulose pad When foods are heated. A steady stream of CO2 gas is produced inside the -dissolved oxygen is driven out package oxygen diffuses slowly back in Pressurized CO2stimulates food remains anaerobic for hours C.botulinum arowth 9/18/2016 8 Characteristics of C. botulinum pH • Minimum pH - Group I – pH 4.6 - Group II – pH 5 • Most fruits and vegetables are acidic enough to inhibit C. botulinum • Oth th diti ff t th Other growth conditions affect th e pH growth response • Molds and yeasts may raise the pH so that C. botulinum growth is allowed Characteristics of C. botulinum Salt and water activity • Sodium chloride acts by decreasing th i i h e water activity • Concentration of salt in the water phase called brine concentration is critical • NaCl , KCl, glucose and sucrose give glucose and sucrose give similar effects • Acidity and preservatives may also affect the water activity Characteristics of C. botulinum Oxygen and redox potential • Amount of oxygen is not the critical variable • Oxygen-reduction potential is the critical variable • Strict anaerobes are generally active at negative redox values • Most foods are low enough to permit growth • Little data – difficult to measure • When foods are heated, - dissolved oxygen is driven out - oxygen diffuses slowly back in - food remains anaerobic for hours UltraZapXtendaPak • Active pad contains additives that produce carbon dioxide, which has bacteriostatic properties Carbon dioxide is used in modified-atmosphere packaging p p • Moisture from the packaged protein is absorbed by the UltraZapXtendaPak cellulose pad • A steady stream of CO gas 2 is produced inside the package • Pressurized CO2 stimulates C. botulinum growth