60-Day Aging Requirement Does Not Ensure Safety of Surface-Mold-Ripened Soft Cheeses Manufactured from Raw or Pasteurized Milk When Listeria monocytogenes Is Introduced as a Postprocessing Contaminant

2008 ◽  
Vol 71 (8) ◽  
pp. 1563-1571 ◽  
Author(s):  
DENNIS J. D'AMICO ◽  
MARC J. DRUART ◽  
CATHERINE W. DONNELLY
Keyword(s):  
Listeria Monocytogenes ◽  
Control Strategies ◽  
Raw Milk ◽  
Growth Potential ◽  
Initial Population ◽  
Population Declines ◽  
Pasteurized Milk ◽  
Holding Period ◽  
High Level ◽  
Similar Growth

Because of renewed interest in specialty cheeses, artisan and farmstead producers are manufacturing surface-mold-ripened soft cheeses from raw milk, using the 60-day holding standard (21 CFR 133.182) to achieve safety. This study compared the growth potential of Listeria monocytogenes on cheeses manufactured from raw or pasteurized milk and held for >60 days at 4°C. Final cheeses were within federal standards of identity for soft ripened cheese, with low moisture targets to facilitate the holding period. Wheels were surface inoculated with a five-strain cocktail of L. monocytogenes at approximately 0.2 CFU/cm2 (low level) or 2 CFU/cm2 (high level), ripened, wrapped, and held at 4°C. Listeria populations began to increase by day 28 for all treatments after initial population declines. From the low initial inoculation level, populations in raw and pasteurized milk cheese reached maximums of 2.96 ± 2.79 and 2.33 ± 2.10 log CFU/g, respectively, after 60 days of holding. Similar growth was observed in cheese inoculated at high levels, where populations reached 4.55 ± 4.33 and 5.29 ± 5.11 log CFU/g for raw and pasteurized milk cheeses, respectively. No significant differences (P < 0.05) were observed in pH development, growth rate, or population levels between cheeses made from the different milk types. Independent of the milk type, cheeses held for 60 days supported growth from very low initial levels of L. monocytogenes introduced as a postprocess contaminant. The safety of cheeses of this type must be achieved through control strategies other than aging, and thus revision of current federal regulations is warranted.

Occurrence of Listeria monocytogenes in Milk and Dairy Products Produced or Imported Into Morocco

1993 ◽  
Vol 56 (3) ◽  
pp. 256-259 ◽  
Author(s):  
A. EL MARRAKCHI ◽  
A. HAMAMA ◽  
F. EL OTHMANI
Keyword(s):  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Raw Milk ◽  
Listeria Innocua ◽  
Pasteurized Milk ◽  
Listeria Species ◽  
Fresh Cheese ◽  
Milk And Dairy Products

Examination of 227 samples of milk and dairy products for Listeria monocytogenes showed that raw milk and some Moroccan traditionally made dairy products such as Iben and raib (fermented milks) and jben (fresh cheese) were contaminated with this pathogen. L. monocytogenes was the only Listeria species isolated except in one case in which it was associated with Listeria innocua. Pasteurized milk, fresh cream, and fresh and ripened cheeses (industrially made) were free from L. monocytogenes.

scholarly journals Microbiological analysis of raw milk, pasteurized milk and yogurt samples collected from different areas of Dhaka city, Bangladesh

2015 ◽  
Vol 39 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Tasmina Rahman ◽  
Tanzia Akon ◽  
Iftikharun Nessa Sheuli ◽  
Naima Hoque
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Count ◽  
Raw Milk ◽  
Total Coliform ◽  
Microbiological Analysis ◽  
Dhaka City ◽  
Salmonella Spp ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Shigella Spp

A total of 300 different milk and yogurt samples were collected from Dhaka city and analyzed for total viable bacterial count (TVBC), total coliform count (TCC) and presence of several pathogens such as Escherichia coli, Salmonella spp., Shigella spp., Vibrio spp. and Listeria monocytogenes. Raw milk samples collected from Moghbazar area showed highest TVBC (4.2 × 106 cfu/ml) and samples from Mohammadpur area showed lowest count (3.5 × 103 cfu/ml). All the pasteurized milk samples showed TVBC of 1.9 × 102 to 2.8 × 103 cfu/ml, and TCC only in one sample Yogurt samples (open) collected from vendor showed TVBC of 9.1 × 103 to 8.2 × 107 cfu/ml, and TCC only in sample collected from Dhanmondi, Dhaka. The packed yogurt samples showed TVBC of 2.2 × 102 to 6.1 × 103 cfu/ml, and TCC only in one sample. All the milk and yogurt samples were found contaminated with E. coli and Shigella-like species. Listeria monocytogenes was not detected in any of the samples studied.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 31-36, 2015

scholarly journals Prevalence and Characterization of Listeria Species from Raw Milk and Dairy Products from Çanakkale Province

2018 ◽  
Vol 6 (1) ◽  
pp. 61 ◽  
Author(s):  
Pınar Şanlıbaba ◽  
Başar Uymaz Tezel
Keyword(s):  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Common Species ◽  
Food Samples ◽  
Pasteurized Milk ◽  
Listeria Species ◽  
Test Kit ◽  
White Cheese ◽  
Listeria Welshimeri

The objective of this study was to determine the prevalence of Listeria species, specifically Listeria monocytogenes, in raw milk, pasteurized milk, white cheese, and homemade cheese. A total of 200 food samples were collected and analyzed to examine the presence of Listeria spp. The EN ISO 11290-1 method was used for isolation of Listeria. API Listeria test kit was used for biochemically characterization. Listeria spp. were isolated in 25 of the 200 samples (12.5%). The largest number of Listeria spp. was detected in homemade cheese (24%), followed by raw milk (18%), and white cheese (8%). Listeria spp. were not isolated from the pasteurized milk. The most common species isolated were Listeria innocua (5.5%); the remaining Listeria isolates were Listeria ivanovi (3.5%), Listeria welshimeri (3%), and Listeria monocytogenes (0.5%). Listeria monocytogenes was detected in only raw milk.

scholarly journals Predictive Microbiology of Dairy Products: Influence of Biological Factors Affecting Growth of Listeria monocytogenes

1997 ◽  
Vol 80 (4) ◽  
pp. 913-919 ◽  
Author(s):  
Agnes Brouillaud-Delattre ◽  
Murielle Maire ◽  
Catherine Collette ◽  
Cesar Mattei ◽  
Cecille Lahellec
Keyword(s):  
Listeria Monocytogenes ◽  
Low Temperature ◽  
Dairy Products ◽  
Physiological State ◽  
Raw Milk ◽  
Growth Potential ◽  
Strain Effect ◽  
Biological Factors ◽  
Factors Affecting ◽  
Different Strains

Abstract The growth potential of Listeria monocytogenes was evaluated at low temperature in sterilized milk and raw dairy products. Sterilized and raw milk were inoculated with different strains of L. monocytogenes in 2 physiological states and at various contamination levels. Raw cheese was naturally contaminated with Listeria spp. The results suggest that some biological factors influence the growth capacity of L. monocytogenes in dairy products. Significant strain effect was observed at low temperature whatever the growth medium. By contrast, no inoculum effect was observed in the 3 dairy products. In raw matrixes, growth of L. monocytogenes was influenced greatly by bacterial interactions and physiological state of inoculum cells.

scholarly journals Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia

2015 ◽  
Vol 9 (11) ◽  
pp. 1204-1209 ◽  
Author(s):  
Eyasu Tigabu Seyoum ◽  
Daniel Asrat Woldetsadik ◽  
Tesfu Kassa Mekonen ◽  
Haile Alemayehu Gezahegn ◽  
Wondwossen Abebe Gebreyes
Keyword(s):  
Listeria Monocytogenes ◽  
Urban Areas ◽  
Dairy Products ◽  
Pathogenic Bacteria ◽  
Bovine Milk ◽  
Raw Milk ◽  
Milk Product ◽  
Milk Products ◽  
Pasteurized Milk ◽  
Processing Plants

Introduction: Listeria monocytogenes is of major significance in human and veterinary medicine. Most human Listeria infections are foodborne and the association of contaminated milk and dairy produce consumption with human listeriosis is noteworthy. In Ethiopia, there is limited data regarding the prevalence of L. monocytogenes in raw bovine milk and dairy products. The aim of this study was, therefore, to determine the prevalence of L. monocytogenes in raw bovine milk and dairy produce. Methodology: A total of 443 milk and milk product samples were microbiologically analyzed following methods recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual to isolate Listeria spp. Results: The overall prevalence of Listeria spp. was 28.4% and specifically that of L. monocytogenes was 5.6%. Taking the prevalence of Listeria spp. into consideration, cheese was found to be highly contaminated at 60%, followed by pasteurized milk samples (40%), raw milk (18.9%) and yoghurt (5%). Considering the prevalence of Listeria monocytogenes only, raw milk had the lowest contamination while cheese had the highest, followed by pasteurized milk and yoghurt. Conclusions: Raw milk and milk products produced in urban and peri-urban areas of central Ethiopia were contaminated with pathogenic bacteria, L. monocytogenes. The detection of this pathogen in raw milk and milk products warrants an urgent regulatory mechanism to be put in place and also the potential role of milk processing plants in the contamination of dairy products should be investigated.

scholarly journals Assessment of listeria monocytogenes, staphylococcus aureus and salmonella SPP. Contamination in dairy samples collected in Gia Lam and Ba Vi, Hanoi early 2019

2019 ◽  
Vol 2 (4) ◽  
pp. 22-32
Author(s):  
Minh Huyen Nguyen Thi ◽  
Hoa Tran Thi ◽  
Tuyet Lan Ninh Thi ◽  
Hien Tran Thi ◽  
◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Pathogenic Bacteria ◽  
Raw Milk ◽  
Accurate Method ◽  
Salmonella Spp ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Milk And Dairy Products

Milk and dairy products from dairy farms around Hanoi greatly contribute to the consumed milk quantity in Hanoi. The use of fresh milk or pasteurized milk becomes more and more popular in the daily life of local people. Milk and dairy products were widely sold in numerous stores, particularly in Xuan Mai, Ba Vi, Phu Dong and Gia Lam. However, there have not yet been any studies to assess the pathogenic bacterial contamination of these products. In our study, 49 samples including 23 raw milk samples, 12 pasteurized milk samples, and 14 yogurt samples were collected in order to examine the presence of food­born pathogenic bacteria such as Listeria monocytogenes, Staphylococcus aureus, Salmonella spp. using PCR method. This fast and accurate method works based on the specific amplification of tested bacterial DNA. The results showed that one of the samples may contain Staphylococcus aureus while another may be contaminated with Listeria monocytogenes. None of the samples was contaminated with Salmonella spp. The results were confirmed by gene sequencing.

SIMULATION OF INTEGRATED CONTROL STRATEGIES FOR OROBANCHE SPP. BASED ON A LIFE CYCLE MODEL

2001 ◽  
Vol 37 (1) ◽  
pp. 37-51 ◽  
Author(s):  
E. KEBREAB ◽  
A. J. MURDOCH
Keyword(s):  
Seed Bank ◽  
Control Strategies ◽  
Soil Seed Bank ◽  
Integrated Control ◽  
Integrated Approach ◽  
Cultural Control ◽  
Computer Simulation Model ◽  
Weed Species ◽  
Hand Weeding ◽  
High Level

A computer simulation model was developed to investigate strategies for control of the parasitic weed species of Orobanche. The model makes use of data from published literature and predicts infestation levels in a dynamic and deterministic way. It is predicted that sustainable control of the parasite can only be achieved by reducing the soil seed bank to levels of 1000–2000 seeds m−2 and maintaining it at that level in subsequent years. When cultural control methods such as hand weeding, trap/catch cropping, delayed planting, resistant cultivars and solarization were considered individually, a relatively high level of effectiveness was required to contain the soil seed bank. An integrated approach with a selection of appropriate cultural methods is therefore recommended for further testing and validation in the field. The simulations demonstrate the importance of preventing new seeds entering the soil seed bank and that although reducing the soil seed bank may not increase yield for the first few years, it will ultimately increase production.

Effect of Phage on Survival of Salmonella Enteritidis during Manufacture and Storage of Cheddar Cheese Made from Raw and Pasteurized Milk

2001 ◽  
Vol 64 (7) ◽  
pp. 927-933 ◽  
Author(s):  
RAJESH MODI ◽  
Y. HIRVI ◽  
A. HILL ◽  
M. W. GRIFFITHS
Keyword(s):  
Lactic Acid ◽  
Salmonella Enteritidis ◽  
Cheddar Cheese ◽  
Raw Milk ◽  
Final Concentration ◽  
Pasteurized Milk ◽  
Ph Values ◽  
Standard Procedures ◽  
Raw Milk Cheese ◽  
And Storage

The ability of Salmonella Enteritidis to survive in the presence of phage, SJ2, during manufacture, ripening, and storage of Cheddar cheese produced from raw and pasteurized milk was investigated. Raw milk and pasteurized milk were inoculated to contain 104 CFU/ml of a luminescent strain of Salmonella Enteritidis (lux) and 108 PFU/ml SJ2 phage. The milks were processed into Cheddar cheese following standard procedures. Cheese samples were examined for Salmonella Enteritidis (lux), lactic acid bacteria, molds and yeasts, coliforms, and total counts, while moisture, fat, salt, and pH values were also measured. Salmonella Enteritidis (lux) was enumerated in duplicate samples by surface plating on MacConkey novobiocin agar. Bioluminescent colonies of Salmonella Enteritidis were identified in the NightOwl molecular imager. Samples were taken over a period of 99 days. Counts of Salmonella Enteritidis (lux) decreased by 1 to 2 log cycles in raw and pasteurized milk cheeses made from milk containing phage. In cheeses made from milks to which phage was not added, there was an increase in Salmonella counts of about 1 log cycle. Lower counts of Salmonella Enteritidis (lux) were observed after 24 h in pasteurized milk cheese containing phage compared to Salmonella counts in raw milk cheese with phage. Salmonella Enteritidis (lux) survived in raw milk and pasteurized milk cheese without phage, reaching a final concentration of 103 CFU/g after 99 days of storage at 8°C. Salmonella did not survive in pasteurized milk cheese after 89 days in the presence of phage. However, Salmonella counts of approximately 50 CFU/g were observed in raw milk cheese containing phage even after 99 days of storage. In conclusion, this study demonstrates that the addition of phage may be a useful adjunct to reduce the ability of Salmonella to survive in Cheddar cheese made from both raw and pasteurized milk.

Growth potential of Listeria monocytogenes in ready‐to‐eat Feta cheese‐based sauce stored at 4°C

2018 ◽  
Vol 39 (2) ◽  
pp. e12599
Author(s):  
Nikolaos D. Andritsos ◽  
Theodoros Kallitsis ◽  
Dimokritos Roukas
Keyword(s):  
Listeria Monocytogenes ◽  
Growth Potential ◽  
Feta Cheese
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