Modelling the effects of modified atmosphere onSalmonella typhimurium in packaged meat during storage in the refrigerator and at 12°C

Abstract

Summary -The effects of storage atmosphere and temperatures on Salmonella typhimurium and aerobic plate count (APC) in meat were studied. Experimental results were analysed by non-linear regression of modified-Gompertz and logistic equations to generate "best fit". In the absence of CO 2 in package (with air and 40% O 2 + 60% N 2 ), in the refrigerator and at 12 o C, S. typhimurium had higher growth rate and reached to higher number, whereas the presence of CO 2 from 40 to 100% reduced the number of S. typhimurium by 0.2 to 1.6 logs unit in the refrigerator. CO 2 dissolves in water to form carbonic acid which reduces pH of meat and bacterial cytoplasm. This would be reduced the bacteria or inhibited their growth. The effects of the modified atmospheres on microorganisms in meat seems to be responsible for the data obtained, together with a probable contribution from pH which in turns is likely to be influenced by the gas atmosphere. It is known that CO 2 has a bacteriostatic effect. Parameters of non-linear modified-Gompertz and logistic models of the S. typhimurium and APC in meat stored at various atmospheres were matched in a satisfactory way. Both the modified-Gompertz and logistic models showed good fit to all curves as assessed using the root mean square error and the correlation coefficient between the experimental and predicted values.

Salmonella Behavior in Meat during Cool Storage: A Systematic Review and Meta-Analysis

“…A total of 155 duplicate articles were found. After initial title, abstract, and full article reading, 83 studies [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ,…”

“…One study, for example, observed a reduction between 1.4 and 1.9 log CFU g −1 in Salmonella concentrations in ground beef packed under a vacuum and in a modified atmosphere at 3 °C for 12 days [ 17 ]. In another study, 0.17 and 0.97 log CFU Salmonella -concentration decreases were detected in modified-atmosphere packed (MAP) beef stored at 7.5 °C for 12 days, although a 1.69 log CFU g −1 pathogen reduction was observed in vacuum-packed beef in the same study [ 42 ].…”

Growth characteristics of Escherichia coli O157:H7 on sliced meat at temperature abuse conditions

“…Two gases, CO 2 and N 2 are commonly used in MAP, the first being mainly responsible for the bacteriostatic or bactericidal effect on microorganisms. For meat and meat products, red color maintenance is important (Erkmen and Barazi, 2008;Erkmen and Bozoglu, 2008a). During storage of E. coli O157:H7 inoculated sliced meat at 4°C in 30% CO 2 atmosphere, the pathogen showed significant (p0.05) reduction compared to similar conditions in air.…”

“…Fax: +90 3423601011. product storage (Erkmen and Bozoglu, 2008a). Pathogen behavior on raw meats, as with many other foods, is controlled by several interrelated factors, such as temperature of storage, atmosphere composition and competitive microflora (ICMSF, 1998;Erkmen and Barazi, 2008;Erkmen and Bozoglu, 2008a). The current assumption is that E. coli O157:H7 does not multiply below 7°C, which is the endpoint generally accepted by the European Union as an appropriate temperature to prevent mesophilic pathogen growth (Anon, 2004).…”