Effects of acid adaptation and modified marinades on survival of postdrying salmonella contamination on beef jerky during storage

• Published in: Journal of food protection 2003-03, Vol.66 (3), p.396-402
• Main Authors: Calicioglu, M, Sofos, J.N, Kendall, P.A, Smith, G.C
• Format: Article
• Language: English
• Subjects: acetic acid; acid tolerance; Adaptation, Physiological; ambient temperature; Animals; bacterial contamination; beef; Biological and medical sciences; Cattle; Colony Count, Microbial; cured meats; dried meat; food contamination; Food Handling - methods; Food industries; Food Microbiology; food pathogens; food preservatives; food processing quality; food storage; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; lactates; marinating; Meat and meat product industries; Meat Products - microbiology; pathogen survival; Salmonella; Salmonella - growth & development; Salmonella - physiology; storage temperature; stress tolerance; Temperature; Time Factors; viability; water activity
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-66.3.396

This study was undertaken to evaluate the survival of acid-adapted and nonadapted Salmonella cultures inoculated after drying on beef jerky that had been treated with marinades before drying at 60 degrees C for 10 h. Beef slices were (i) not treated prior to refrigeration at 4 degrees C for 24 h (control [C]); (ii) marinated with traditional marinade (TM), (iii) marinated with TM modified with 1.2% sodium lactate, 9% acetic acid, and 68% soy sauce containing 5% ethanol (MM) at twice the amount used in the TM treatment; (iv) dipped into 5% acetic acid and then marinated with TM (AATM); and (v) dipped into 1% Tween 20, then dipped into 5% acetic acid, and then marinated with TM (TWTM); after each treatment, meat slices were refrigerated at 4 degrees C for 24 h prior to drying. Dried slices were inoculated with acid-adapted or nonadapted Salmonella (ca. 5.7 log CFU/cm2) prior to aerobic storage at 25 degrees C for 60 days. Tryptic soy agar with 0.1% pyruvate, as well as xylose-lysine-tergitol 4 (XLT4) agar, was used to determine survivor counts. Bacterial decreases achieved with the different treatments were found to be in the following order: TWTM (5.4 to 6.3 log units) > or = AATM > or = MM > C > or = TM (2.9 to 5.1 log units). Acid-adapted Salmonella decreased faster than nonadapted Salmonella for all treatments. Bacterial populations decreased to below the detection limit (-0.4 log CFU/cm2) in as few as 14 days or remained detectable by direct plating after 60 days of storage, depending on acid adaptation, treatment, and agar media. The results of this study indicate that the modified marinades used in jerky processing and the low water activity of the dried product provide antimicrobial effects against possible postprocessing contamination with Salmonella, while the preparation of cultures under acid-adaptation conditions did not increase Salmonella survival during storage and may have reduced it.