Injury, Inhibition and Inactivation ofEscherichia coli O157:H7 by Potassium Sorbate and Sodium Nitrite as Affected by pH and Temperature

✍ Scribed by Tsai, Shaur-huei; Chou, Cheng-chun

• Book ID: 101223638
• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 235 KB
• Volume: 71
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199605)71:1<10::aid-jsfa531>3.0.co;2-7

✦ Synopsis

The effect of potassium sorbate (0-2 g litre-') and sodium nitrite (0-1 g litre-') on the growth of four strains of Escherichia coli 0157 : H7 in tryptic soya broth at various pH levels (pH 4.0-7.0 for sorbate, pH 5.0-8.0 for nitrite) were determined at 37°C and 4°C. Among the pH levels tested, sorbate and nitrite exhibited the highest antimicrobial activity at pH 4.0 and 5.0, respectively. At pH 5.0 and 3 7 T , the presence of 500 mg litre-' sorbate or 200 mg litre-' nitrite completely inhibited the growth of E coli 0157: H7. While at higher pH levels, 2 g litre-' sorbate or I g litre-', nitrite, the highest concentration tested, did not show significant antimicrobial action against the test organisms. At 4°C and pH 5.0, the inoculated test organisms did not showed any significant growth in preservative-free control media. Different degree of inactivation and injury was observed when E coli 0157 : H7 strain 933 was stored in TSB (pH 5.0) containing 1 g litre-' sorbate or nitrite at 37°C. At 4"C, inactivation and injury of E coli 0157 : H7 cells was not observed in the medium containing sorbate or nitrite throughout the 24 h experimental period.