Listeria monocytogenes in Fish Products

1991 ◽  
Vol 54 (12) ◽  
pp. 922-924 ◽  
Author(s):  
J. M. FARBER
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Health Hazard ◽  
Fish Products ◽  
Limited Sampling ◽  
Smoked Salmon ◽  
Low Levels

A limited sampling of fish products at both the wholesale and retail levels demonstrated that ready-to-eat fish products such as shrimp and smoked salmon are often contaminated with Listeria monocytogenes. This study shows that growth of the organism at 4°C occurred on artificially inoculated cooked crabmeat, lobster, shrimp, and smoked salmon. The organism generally grew better on crab and lobster. L. monocytogenes was also observed to multiply slowly on naturally contaminated shrimp. Given the low levels of L. monocytogenes found on cooked fish products and their relatively short shelf life, unless these products are temperature abused, Listeria contaminated fish should not represent a serious health hazard.

Fate of Salmonella spp., Listeria monocytogenes,and Indigenous Spoilage Microorganisms in Home-style Salads Prepared with Commercial Real Mayonnaise or Reduced Calorie Mayonnaise Dressings

1993 ◽  
Vol 56 (12) ◽  
pp. 1015-1021 ◽  
Author(s):  
JOHN P. ERICKSON ◽  
DENISE N. MCKENNA ◽  
MARIE A. WOODRUFF ◽  
JILL S. BLOOM
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Leuconostoc Mesenteroides ◽  
Competitive Inhibition ◽  
Health Hazard ◽  
Salmonella Spp ◽  
Microbial Spoilage ◽  
Reduced Fat ◽  
Home Style ◽  
Spoilage Microorganisms

Two home-style salads, chicken and macaroni, were prepared with three different commercial mayonnaise products: (i) real mayonnaise, (ii) reduced calorie mayonnaise dressing, and (iii) reduced calorie/reduced fat mayonnaise dressing. The salads were inoculated with 103/ml levels of Salmonella spp. or Listeria monocytogenes and held at 4°C (refrigeration) and 12.8°C (temperature abuse) for 10 and 2 d, respectively. Uninoculated controls were evaluated to determine the refrigerated shelf-life limit and microbial spoilage profile of both salads. Salmonella spp. growth occurred in the temperature-abused chicken salad, while L. monocytogenes grew in the temperature-abused and refrigerated chicken salad. The synergistic combination of mayonnaise and refrigeration inhibited L. monocytogenes outgrowth for >7 d. The microbiological shelf life of refrigerated chicken and pasta salads was 5 and 7 d, respectively. Microbial spoilage was predominantly caused by heterofermentative lactic acid bacteria, of which Leuconostoc mesenteroides was the most important. The organism was psychotropic and exhibited competitive inhibition against Salmonella spp. The latter was attributed to diacetyl formation synergistically interacting with the acidic salad environment. No microbiological safety or spoilage differences were observed between the salads prepared with real mayonnaise or reduced calorie mayonnaise dressings. Under proper refrigeration and good hygienic practices, home-style salads made with commercial real mayonnaise/mayonnaise dressings represent negligible microbial health hazard risks to consumers.

scholarly journals Growth Potential of Listeria monocytogenes in Three Different Salmon Products

Foods ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1048 ◽  
Author(s):  
Corinne Eicher ◽  
Andres Ruiz Subira ◽  
Sabrina Corti ◽  
Arnulf Meusburger ◽  
Roger Stephan ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Challenge Test ◽  
High Growth ◽  
Growth Potential ◽  
High Concentration ◽  
Food Borne ◽  
Smoked Salmon ◽  
Good Manufacturing Practices ◽  
Challenge Tests ◽  
Low Levels

Cold smoked salmon and sushi salmon have been implicated in outbreaks of listeriosis. We performed challenge tests and a durability study with Listeria monocytogenes on different salmon products to determine the growth potential of this important food-borne pathogen. Data from the challenge test showed a significant growth potential of L. monocytogenes on all of the tested salmon products, with faster growth in sushi salmon than in cold smoked salmon. In identical products that were naturally contaminated at low levels, the durability study did not confirm a high growth potential, possibly due to interactions with competing microflora. The injection of sodium lactate (NaL) at a high concentration (30%) into cold smoked salmon significantly reduced the growth potential of L. monocytogenes. In addition to good manufacturing practices, the injection of higher concentrations of NaL may therefore be a useful additional hurdle to prevent growth of L. monocytogenes to high numbers in the tested salmon products.

Antilisterial Activity of a Carnobacterium piscicola Isolated from Brazilian Smoked Fish (Surubim [Pseudoplatystoma sp.]) and Its Activity against a Persistent Strain of Listeria monocytogenes Isolated from Surubim

2005 ◽  
Vol 68 (10) ◽  
pp. 2068-2077 ◽  
Author(s):  
VIRGÍNIA F. ALVES ◽  
ELAINE C. P. DE MARTINIS ◽  
MARIA TERESA DESTRO ◽  
BIRTE FONNESBECH VOGEL ◽  
LONE GRAM
Keyword(s):  
Listeria Monocytogenes ◽  
Freshwater Fish ◽  
Random Amplified Polymorphic Dna ◽  
Model Systems ◽  
Fish Products ◽  
Tropical Regions ◽  
Smoked Fish ◽  
Smoked Salmon ◽  
Carnobacterium Piscicola

Data on the prevalence and growth of Listeria monocytogenes in lightly preserved fish products from subtropical and tropical regions are very scarce. Our research describes L. monocytogenes that was detected in 5% of the packages of cold-smoked surubim, a native Brazilian freshwater fish that we analyzed, and shows that the strains isolated were of the same random amplified polymorphic DNA subtype as the strains that were isolated from the same factory 4 years earlier. A bacteriocinogenic strain of Carnobacterium piscicola (strain C2), isolated from vacuum-packed cold-smoked surubim, and two C. piscicola strains, isolated from vacuum-packed, cold-smoked salmon, were capable of limiting or completely inhibiting the growth of an L. monocytogenes (strain V2) isolated from surubim in fish peptone model systems incubated at 10°C. Mono-cultures of L. monocytogenes reached 108 CFU/ml (g), whereas the growth of L. monocytogenes was completely inhibited by C. piscicola C2. The bacteriocinogenic C. piscicola A9b+ and its nonbacteriocinogenic mutant A9b− reduced maximum Listeria levels by 2 to 3 log units. Both bacteriocinogenic C. piscicola strains prevented listerial growth in cold-smoked fish juices (surubim and salmon). Although the carnobacteria grew poorly on cold-smoked surubim at 10°C, the strains were able to reduce maximum Listeria counts by 1 to 3 log units in an artificially inoculated product (surubim). We conclude that Brazilian smoked fish products harbor L. monocytogenes and should be stabilized against the growth of the organism. C. piscicola C2 has the potential for use as a bioprotective culture in surubim and other lightly preserved fish, but further studies are required to optimize its effect.

scholarly journals Identification and serotyping of Listeria monocytogenes, isolated from various salmon products, sold in retail market in Lithuania

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Ineta Simonavičienė ◽  
Gintarė Zakariene ◽  
Aušra Lozoraitytė ◽  
Gintarė Zaborskienė ◽  
Gediminas Gerulis ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Local Market ◽  
Microbiological Analysis ◽  
Retail Market ◽  
Fish Products ◽  
Smoked Fish ◽  
Smoked Salmon ◽  
Study Results ◽  
Fish Product

Cold smoked salmon products (belly flaps, pieces, fillet, and loin) obtained from the retail market in Lithuania were tested for the presence of L. monocytogenes. It was found that contamination of the cold smoked fish products with Listeria spp. depends on the type of the product. Contamination with listeria in salmon belly flaps was 7.5 times higher than in the loin (P<0.05), 1.8 times higher than in the pieces (P<0.05) and 30 times higher than in the fillet (P<0.05). Microbiological analysis showed that 32.5% (P<0.05) of the fish product samples were infected with L. monocytogenes, while multiplex PCR confirmed 31.25% positive samples (P<0.01). According to the study results, L. monocytogenes strains were divided into two serotypes: 4b (94.6%) and 1/2a (5.4%). High contamination of the products with Listeria spp. showed that cold smoked salmon products, sold in local market, can be a reason of human listeriosis in Lithuania.

scholarly journals Rapid Determination of Listeria monocytogenes by Automated Enzyme-Linked Immunoassay and Nonradioactive DNA Probe

2000 ◽  
Vol 83 (1) ◽  
pp. 86-88 ◽  
Author(s):  
Khalil F Kerdahi ◽  
Philip F Istafanos
Keyword(s):  
Listeria Monocytogenes ◽  
Rapid Determination ◽  
Food Samples ◽  
Dna Probe ◽  
Negative Results ◽  
Smoked Salmon ◽  
Colony Forming Units ◽  
Low Levels ◽  
Analytical Time

Abstract A rapid and reliable analytical method was developed to detect and confirm the presence of Listeria monocytogenes in raw and partially processed foods. Forty-nine food samples (25 mixed cut vegetable salad, 12 smoked salmon, and 12 sterile smoked salmon) were individually inoculated with high levels [10–100 colony forming units (cfu)/25 g sample] and low levels (1–10 cfu/25 g sample) of L. monocytogenes, and were screened using the Vitek Immuno Diagnostic Assay (VIDAS) Listeria monocytogenes (VIDAS LMO)]. Positive test results were confirmed as L. monocytogenes by nonradioactive DNA probe. All samples inoculated with high levels of L. monocytogenes were detected by VIDAS and 96% were confirmed as L. monocytogenes by DNA probe. VIDAS LMO detected 89% of samples inoculated with low levels of L. monocytogenes, and 87% of these were confirmed as positive by DNA probe. In addition, 12 other samples (4 from each of mixed cut vegetable salad, smoked salmon, and sterile smoked salmon) were inoculated with high levels of L. ivanovii, L. seeligeri, L. welshimeri, L. innocua, L. grayi, and L. murrayi. Samples were assayed by the same protocol and all gave negative results. Compared with the cultural method, the VIDAS LMO nonradioactive DNA probe combination is highly specific, discriminates between L. monocytogenes and all other Listeria species, and reduces analytical time.

Psychrotrophic Lactic Acid Bacteria Used To Improve the Safety and Quality of Vacuum-Packaged Cooked and Peeled Tropical Shrimp and Cold-Smoked Salmon

2009 ◽  
Vol 72 (2) ◽  
pp. 365-374 ◽  
Author(s):  
S. MATAMOROS ◽  
F. LEROI ◽  
M. CARDINAL ◽  
F. GIGOUT ◽  
F. KASBI CHADLI ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Pathogenic Bacteria ◽  
Smoked Salmon ◽  
Seafood Products ◽  
Challenge Tests ◽  
Leuconostoc Gelidum

Previously isolated lactic acid bacteria (LAB) from seafood products have been investigated for their capacity to increase the sensory shelf life of vacuum-packaged shrimp and cold-smoked salmon and to inhibit the growth of three pathogenic bacteria. Two different manufactured batches of cooked, peeled, and vacuum-packaged shrimp were inoculated with seven LAB strains separately at an initial level of 5 log CFU g−1, and the spoilage was estimated by sensory analysis after 7 and 28 days of storage at 8°C. Two Leuconostoc gelidum strains greatly extended the shelf life of both batches, two Lactococcus piscium strains had a moderate effect, two bacteria were spoilers (Lactobacillus fuchuensis and Carnobacterium alterfunditum), and the last one (another Leuconostoc gelidum strain) showed highly variable results depending on the batch considered. The four strains showing the best results (two Leuconostoc gelidum and two Lactococcus piscium strains) were selected for the same experiment in cold-smoked salmon. In this product, Lactococcus piscium strains showed better inhibiting capacities, improving the sensory quality significantly at 14 and 28 days of storage. Finally, the inhibiting capacities of two strains (one Leuconostoc gelidum strain and one Lactococcus piscium strain) were tested against three pathogenic bacteria (Vibrio cholerae, Listeria monocytogenes, and Staphylococcus aureus) by challenge tests in shrimp. LAB and pathogenic bacteria were coinoculated in vacuum-packaged shrimp and enumerated during 5 weeks. Lactococcus piscium strain EU2241 was able to reduce significantly the number of Listeria monocytogenes and S. aureus organisms in the product by 2 log throughout the study for Listeria monocytogenes and up to 4 weeks for S. aureus.

Impact of−2°C Superchilling before Refrigerated Storage (4 and 8°C) on the Microbiological and Sensory Qualities of Cold-Smoked Salmon

2008 ◽  
Vol 71 (11) ◽  
pp. 2198-2207 ◽  
Author(s):  
GRAZIELLA MIDELET-BOURDIN ◽  
ANNIE BEAUFORT ◽  
FRANÇOISE LEROI ◽  
MIREILLE CARDINAL ◽  
SYLVIE RUDELLE ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Sensory Characteristics ◽  
Refrigerated Storage ◽  
Genetic Groups ◽  
Smoked Salmon ◽  
Spoilage Bacteria ◽  
Serotype 1 ◽  
Sensory Qualities

Detection and enumeration of Listeria monocytogenes and total spoilage bacteria in 40 batches of cold-smoked salmon (one batch = 42 products from the same day of manufacture) straight from the factory were carried out. If L. monocytogenes was detected in at least one of the nine samples analyzed on receipt at the laboratory, 9 products of the same batch were stored for 10 days at 4°C, which was followed by 18 days at 8°C (control), 12 products were superchilled for 14 days at −2°C, and 12 other products were superchilled for 28 days at −2°C and then stored under the same conditions as the control was stored. L. monocytogenes was detected in 7% of the 40 batches analyzed immediately after receipt at the laboratory. L. monocytogenes prevalence was similar (approximately 25%) throughout the storage at 4 and 8°C, both in control and super-chilled products at −2°C for 14 days. After superchilling for 28 days at −2°C, L. monocytogenes was found in 9% of products, and in 39% at the end of the storage above 0°C. Moreover, the L. monocytogenes count was higher after 3 and 4 weeks of storage at 4 and 8°C in products superchilled 28 days at −2°C than in control products or in products superchilled for 14 days. Serotype 1/2a-3a and nine genetic groups were identified and found throughout the storage scenario. At the end of shelf life, sensory characteristics of products superchilled for 28 days at −2°C were slightly modified. A decrease in firmness associated with increased tearing of salmon slices was observed as well as a slight amine odor.

scholarly journals Analysis of the Bioprotective Potential of Different Lactic Acid Bacteria Against Listeria monocytogenes in Cold-Smoked Sea Bass, a New Product Packaged Under Vacuum and Stored at 6 ± 2°C

2021 ◽  
Vol 12 ◽  
Author(s):  
Lucilla Iacumin ◽  
Giorgia Cappellari ◽  
Michela Pellegrini ◽  
Marco Basso ◽  
Giuseppe Comi
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Storage Temperature ◽  
Enrichment Culture ◽  
Starter Culture ◽  
Sea Bass ◽  
New Product ◽  
Fish Products ◽  
Smoked Fish ◽  
Different Strains

The aim of the work was to monitor the presence of Listeria monocytogenes in cold-smoked fish products (trout, salmon, and sea bass) marketed in Italy. Cold-smoked sea bass is a new product that has not yet been commercialized and was collected from the production facility. Monitoring data have shown that cold-smoked products can be contaminated by L. monocytogenes, the presence of which has been highlighted mainly by enrichment culture (presence in 25 g). The isolated Listeria were serotyped and belonged mainly to low-virulence serotypes (1/2c), followed by serotypes 1/2a, 1/2b, and 4b. Furthermore, considering the ability of L. monocytogenes to grow in these products due to their chemical–physical characteristics (pH &gt; 6.0, Aw &gt; 0.97) and long shelf life at 4°C, an additional aim was to verify the activity of different bioprotective starters, including Lactilactobacillus sakei (LAK-23, Sacco srl, Via Alessandro Manzoni 29/A, 22071 Cadorago, CO, Italy), Carnobacterium spp., Lacticaseibacillus casei (SAL 106), and Lacticaseibacillus paracasei (SAL 211), in cold-smoked sea bass. All starters were bacteriocin producers. For this experiment, smoked sea bass samples were intentionally inoculated with a mixture of three different strains of L. monocytogenes and of each starter culture. After inoculation, the smoked sea bass were vacuum-packed and stored at 6 ± 2°C for 60 days, simulating the typical abuse storage temperature of markets and home refrigerators. At 0, 15, 30, 45, and 60 days, the sea bass samples were analyzed to evaluate the effectiveness of the starters against L. monocytogenes. Listeria monocytogenes growth was prevented only by the addition of the LAK-23 starter. Indeed, at the end of the shelf life, the amount of L. monocytogenes observed was similar to that in the inoculum. Consequently, the use of this starter can allow the inclusion of cold-smoked sea bass or smoked fish products in category 1.3 of Regolamento CE 2073/2005, which are products that do not support the growth of this microorganism. Finally, the activity of the LAK-23 starter did not produce an off flavor or off odor in the smoked sea bass.

scholarly journals Challenge Studies to Determine the Ability of Foods to Support the Growth of Listeria monocytogenes

Pathogens ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 80 ◽  
Author(s):  
Karen Hunt ◽  
Marjorie Blanc ◽  
Avelino Álvarez-Ordóñez ◽  
Kieran Jordan
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Foodborne Pathogen ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Reference Laboratory ◽  
Guidance Document ◽  
The European Union ◽  
European Union Reference Laboratory ◽  
Smoked Salmon

: Listeria monocytogenes is a foodborne pathogen that causes listeriosis, a relatively rare, but potentially fatal, disease, with a mortality rate of 20–30%. In general, European Regulations require the absence of L. monocytogenes in five samples of 25 g before the food has left the producer, but if the food has been demonstrated not to support the growth of L. monocytogenes, up to 100 cfu g-1 are allowed in the food (except for foods for infants or medical purposes) during its shelf-life under reasonably foreseeable storage conditions. It is important for food producers to determine if their food supports the growth of L. monocytogenes. The European Union Reference Laboratory for L. monocytogenes published a Technical Guidance document for conducting shelf-life studies on L. monocytogenes in ready-to-eat foods in June 2014. Primarily based on the EURL guidance document for conducting challenge studies, the ability of cheese (feta and soft goat’s milk cheese), cold-smoked salmon, coleslaw, and pork pate to support the growth of L. monocytogenes was determined using a starting inoculum of approximately 100 cfu g−1. The cheese and pork pate were incubated at 8 °C for 14 days; the smoked salmon was incubated at 6 °C for 5 days and 8°C for 9 days; and the coleslaw was incubated at 8 °C for 7 days and 12 °C for 14 days. The results showed that the smoked salmon and pork pate supported growth, while coleslaw and cheese did not. From this study, it is evident that there are factors in food other than pH, water activity, and total bacterial count (TBC) that can inhibit the ability of L. monocytogenes to grow in food.

Differential growth of Listeria monocytogenes at 4 and 8°C: Consequences for the Shelf Life of Chilled Products

1996 ◽  
Vol 59 (9) ◽  
pp. 944-949 ◽  
Author(s):  
L. ROSSO ◽  
S. BAJARD ◽  
J. P. FLANDROIS ◽  
C. LAHELLEC ◽  
J. FOURNAUD ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Dairy Products ◽  
Bacterial Population ◽  
Incubation Temperature ◽  
Differential Growth ◽  
Smoked Salmon ◽  
Minced Beef ◽  
Lag Times ◽  
Time Required

Growth rates and lag times of Listeria monocytogenes at 4 and 8°C were compared in dairy products (milk, cream, and cheese), minced beef, and smoked salmon. Results showed that an increase in incubation temperature from 4 to 8°C leads to a significant decrease in time required to reach a given bacterial population density. The decreases were about 50% on cheese surfaces, 60 to 65% in milk and cream, and 75 to 80% in minced beef and smoked salmon. Consequences on the shelf life of chilled products are discussed on the basis of a simple and general linear relationship between the relative decrease in shelf life and generation time. This relationship was experimentally highlighted and theoretically demonstrated.

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