Freezing effects on survival ofListeria monocytogenes in artificially contaminated cold fresh-salmon

Miladi, Hanene; Chaieb, Kamel; Bakhrouf, Amina; Elmnasser, Noura; Ammar, Emna

doi:10.1007/bf03175545

Cited by 24 publications

(35 citation statements)

References 26 publications

(28 reference statements)

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“…Other freezing-related changes in microstructure of fish muscles, such as increase in extracellular space and shrunken muscle fibers, leads to an increased surface area, which provides for more physical space and better access to nutrients (44). Several studies have been conducted to determine the effect of freezing stress on growth of L. monocytogenes on various food products including cold-smoked salmon; fresh salmon; chilled, cooked shrimp; and frankfurters (5,27,31,53). However, the information regarding the impact of process ing and postprocessing handling of food products on growth of L. monocytogenes is limited.…”

Section: Figure 1 Cell Density Of Listeria Monocytogenes Strains Ovementioning

confidence: 99%

“…Among the processing procedures, salting, smoking, and freezing are known to influence the survival and growth of L. monocytogenes (49) on cold-smoked salmon. The effect of freezing stress on the growth of L. monocytogenes has been assessed in cold-smoked salmon; in all cases, L. monocy togenes was inoculated onto cold-smoked salmon prior to freezing (5,27,31,53). Aside from the effect of freezing on L. monocytogenes, freezing salmon before or after smoking causes structural and chemical changes (39,44).…”

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confidence: 99%

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Effect of Curing Method and Freeze-Thawing on Subsequent Growth of Listeria monocytogenes on Cold-Smoked Salmon

Kang¹,

Tang²,

Liu³

et al. 2012

Journal of Food Protection

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The presence of the foodborne pathogen Listeria monocytogenes on cold-smoked salmon is a major concern for the seafood industry. Understanding processing and postprocessing handling factors that affect the ability of this pathogen to grow on cold-smoked salmon is critical for developing effective control strategies. In this study, we investigated the effect of curing method and freeze-thawing of cold-smoked salmon on (i) physicochemical properties and (ii) subsequent growth of genetically diverse strains of L. monocytogenes (inoculated after freeze-thawing) and endogenous lactic acid bacteria. The majority of the measured physicochemical properties were unaffected by freezing and thawing. Overall, wet-cured cold-smoked salmon had higher pH, water activity, and moisture, as well as lower fat, water-phase salt, and phenolic content compared with dry-cured cold-smoked salmon. The curing method and freeze-thawing did not affect growth of endogenous lactic acid bacteria. Freeze-thawing cold-smoked salmon prior to inoculation led to pronounced growth of L. monocytogenes at 7°C. The increase in cell density between days 0 and 30 was significantly (P = 0.0078) greater for cold-smoked salmon that was frozen and thawed prior to inoculation compared with nonfrozen cold-smoked salmon. On dry-cured, freeze-thawed cold-smoked salmon, L. monocytogenes had a lag phase ranging from 3.7 ± 0.1 to 11.2 ± 1.4 days compared with salmon that was wet cured and freeze-thawed, on which L. monocytogenes began to grow within 24 h. Variation in growth among L. monocytogenes strains was also observed, indicating the significance of assessing multiple strains. Further efforts to understand the impact of processing and postprocessing handling steps of cold-smoked salmon on the growth of genetically diverse L. monocytogenes will contribute to improved challenge study designs and data. This, in turn, will likely lead to more reliable and unbiased risk assessments and control measures.

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Section: Figure 1 Cell Density Of Listeria Monocytogenes Strains Ovementioning

confidence: 99%

mentioning

confidence: 99%

Effect of Curing Method and Freeze-Thawing on Subsequent Growth of Listeria monocytogenes on Cold-Smoked Salmon

Kang¹,

Tang²,

Liu³

et al. 2012

Journal of Food Protection

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“…A similar study reported that levels of L. monocytogenes were reduced by less than 1-log in frozen fish and shrimp during three months of storage at −20 °C [29]. Another study investigating survival of L. monocytogenes reported a 3.69-log reduction in frozen salmon inoculated with a high level (10 8 CFU/g) and stored at −20 °C for 12 months [30]. These results indicate that frozen products may carry L. monocytogenes even after months of frozen storage if the products were contaminated with L. monocytogenes .…”

Section: Resultsmentioning

confidence: 99%

Behavior of Salmonella and Listeria monocytogenes in Raw Yellowfin Tuna during Cold Storage

Liu

Mou

2016

Foods

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Behavior of Salmonella and Listeria monocytogenes in raw yellowfin tuna during refrigeration and frozen storage were studied. Growth of Salmonella was inhibited in tuna during refrigerated storage, while L. monocytogenes was able to multiply significantly during refrigerated storage. Populations of Salmonella in tuna were reduced by 1 to 2 log after 12 days of storage at 5–7 °C, regardless levels of contamination. However, populations of L. monocytogenes Scott A, M0507, and SFL0404 in inoculated tuna (104–105 CFU/g) increased by 3.31, 3.56, and 3.98 log CFU/g, respectively, after 12 days of storage at 5–7 °C. Similar increases of L. monocytogenes cells were observed in tuna meat with a lower inoculation level (102–103 CFU/g). Populations of Salmonella and L. monocytogenes declined gradually in tuna samples over 84 days (12 weeks) of frozen storage at −18 °C with Salmonella Newport 6962 being decreased to undetectable level (<10 CFU/g) from an initial level of 103 log CFU/g after 42 days of frozen storage. These results demonstrate that tuna meat intended for raw consumption must be handled properly from farm to table to reduce the risks of foodborne illness caused by Salmonella and L. monocytogenes.

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“…Listeria monocytogenes has been recognized as a human pathogen since 1929 (Jay 2000). Because of its specific population's targets, such as pregnant women and immunocompromised patients, it is classified as an opportunistic pathogen (Miladi et al . 2008).…”

Section: Introductionmentioning

confidence: 99%

CELLULAR LIPID FATTY ACID PROFILES OF REFERENCE AND FOOD ISOLATESLISTERIA MONOCYTOGENESAS A RESPONSE TO REFRIGERATION AND FREEZING STRESS

Miladi

Bakhrouf

Ammar³

2011

Journal of Food Biochemistry

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Cells of three strains of Listeria monocytogenes, one a reference strain ATCC 19115 and two strains isolated from meat, were cold shocked at refrigeration (+4C) and freezing (−20C) temperatures during one night. Then, their fatty acids were extracted and their composition identified by gas chromatography coupled with mass spectrometry. The results showed that low thermal adaptation response of L. monocytogenes ATCC 19115 was different from that of the two recent food isolates L. monocytogenes. The three experimented strains showed a decrease of anteiso‐C17:0 and an increase of anteiso‐C15:0 rates. In addition, after freezing, the cellular fatty acids were detected as a signature of the membrane changes that give rise to such authenticity. The structural modification seems to be an adaptation form, allowing intracellular ice crystallization enhancement during freezing and water mobility during storage. These results demonstrated that the L. monocytogenes studied strains showed various behaviors regarding low‐temperature stress maintaining membrane fluidity. PRACTICAL APPLICATIONS Listeria monocytogenes is prevalent in a variety of foods and ready‐to‐eat products; it may generate a serious public health problem. Nowadays, ready‐to‐eat, chilled and frozen food consumption is continuously increasing. Bacterial strains that can survive at extremely low temperatures adopt special physiological strategies, although the cold‐regulated fatty acid (FA) adjustment is a universal adaptation to low temperatures. To counteract this phenomenon, L. monocytogenes modifies its plasmatic membrane structure to maintain its fluidity at low temperatures, allowing an optimum membrane fluidity that is crucial for bacterial survival. Our study suggested that after freezing, these bacteria underwent several modifications, which are especially critical because they negatively affect bacterial viability and physiological state and induce mechanical damage that leads to cellular death to fight against food invasion with these bacterial species. This work demonstrates the possibility of using membrane FA composition to characterize L. monocytogenes stress‐state as an efficient tool for traceability.

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Freezing effects on survival ofListeria monocytogenes in artificially contaminated cold fresh-salmon

Cited by 24 publications

References 26 publications

Effect of Curing Method and Freeze-Thawing on Subsequent Growth of Listeria monocytogenes on Cold-Smoked Salmon

Effect of Curing Method and Freeze-Thawing on Subsequent Growth of Listeria monocytogenes on Cold-Smoked Salmon

Behavior of Salmonella and Listeria monocytogenes in Raw Yellowfin Tuna during Cold Storage

CELLULAR LIPID FATTY ACID PROFILES OF REFERENCE AND FOOD ISOLATESLISTERIA MONOCYTOGENESAS A RESPONSE TO REFRIGERATION AND FREEZING STRESS

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