Environmental Survey for Listeria Species in California Milk Processing Plants

This survey was undertaken to determine the prevalence of Listeria monocytogenes and Listeria spp. in environmental samples obtained from milk processing plants located throughout California. Identification of Listeria spp. other than L. monocytogenes was not made. Milk processing plants were categorized as to type of product produced and subdivided into areas based on manufacturing activity occurring in that area. A total of 597 environmental samples from 156 plants were analyzed in the six month period of January through July 1987. Listeria spp. were isolated from 75 (12.6%) of the samples. Thirty-eight of the Listeria spp. (50.7%) were identified as L. monocytogenes. Forty-six plants (29.5%) yielded positive results for Listeria spp., of which, 31 plants (19.9%) were positive for L. monocytogenes. Listeria was recovered more frequently from fluid milk product plants and frozen milk product plants. Likewise, Listeria was isolated most frequently from the packaging-filling room location within a plant and least frequently from the raw milk receiving room. Although Listeria spp. was isolated most frequently from the conveyor site, the drain site within a plant location gave a Listeria isolation rate similar to the total number of Listeria positive sites within that plant location.

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Important Vectors for Listeria monocytogenes Transmission at Farm Dairies Manufacturing Fresh Sheep and Goat Cheese from Raw Milk

Journal of Food Protection ◽

10.4315/0362-028x.jfp-10-534 ◽

2011 ◽

Vol 74 (6) ◽

pp. 919-924 ◽

Cited By ~ 32

Author(s):

DAGMAR SCHODER ◽

DANIELA MELZNER ◽

ALOIS SCHMALWIESER ◽

ABDOULLA ZANGANA ◽

PETRA WINTER ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Environmental Samples ◽

Dairy Farms ◽

Raw Milk ◽

Milk Product ◽

Milk Processing ◽

Milk Contamination ◽

Fresh Cheese ◽

Bulk Tank ◽

The Impact

The aim of this study was to determine the transmission routs of Listeria spp. in dairy farms manufacturing fresh cheese made from ovine and caprine raw milk and to evaluate the impact of Listeria monocytogenes mastitis on raw milk contamination. Overall, 5,799 samples, including 835 environmental samples, 230 milk and milk product samples, and 4,734 aseptic half-udder foremilk samples were collected from 53 dairy farms in the dairy intensive area of Lower Austria. Farms were selected for the study because raw milk was processed to cheese that was sold directly to consumers. A total of 153 samples were positive for Listeria spp., yielding an overall prevalence of 2.6%; L. monocytogenes was found in 0.9% of the samples. Bulk tank milk, cheese, and half-udder samples were negative for Listeria spp. Because none of the sheep and goats tested positive from udder samples, L. monocytogenes mastitis was excluded as a significant source of raw milk contamination. L. monocytogenes was detected at 30.2% of all inspected farms. Swab samples from working boots and fecal samples had a significantly higher overall prevalence (P < 0.001) of L. monocytogenes (15.7 and 13.0%, respectively) than did swab samples from the milk processing environment (7.9%). A significant correlation was found between the prevalence of L. monocytogenes in the animal and in the milk processing environment and the silage feeding practices. Isolation of L. monocytogenes was three to seven times more likely from farms where silage was fed to animals throughout the year than from farms where silage was not fed to the animals.

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

The Journal of Infection in Developing Countries ◽

10.3855/jidc.6211 ◽

2015 ◽

Vol 9 (11) ◽

pp. 1204-1209 ◽

Cited By ~ 18

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.

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Molecular Subtyping and Characterization of Psychrotolerant Endospore-Forming Bacteria in Two New York State Fluid Milk Processing Systems

Journal of Food Protection ◽

10.4315/0362-028x-70.10.2354 ◽

2007 ◽

Vol 70 (10) ◽

pp. 2354-2364 ◽

Cited By ~ 49

Author(s):

JASON R. HUCK ◽

NICOLE H. WOODCOCK ◽

ROBERT D. RALYEA ◽

KATHRYN J. BOOR

Keyword(s):

Control Strategies ◽

New York State ◽

Raw Milk ◽

Effective Control ◽

Processing Plant ◽

Milk Processing ◽

High Temperature Short Time ◽

Processing Plants ◽

Processing Continuum ◽

Fluid Milk

Psychrotolerant endospore-forming bacteria Bacillus and Paenibacillus spp. are important spoilage organisms in fluid milk. A recently developed rpoB subtyping method was applied to characterize the diversity and phylogenetic relationships among Bacillus and related sporeformers associated with milk processing systems. Milk samples representing the processing continuum from raw milk to pasteurized products were collected from two fluid milk processing plants, held at 6°C uptothe code date that had been established by each processing plant (i.e., either 18 or 21 days), and plated for bacterial enumeration throughout storage. Bacterial colonies selected to represent the visible diversity in colony morphology on enumeration plates were examined further. Among 385 bacterial isolates characterized, 35% were Bacillus spp., and 65% were Paenibacillus spp. A total of 92 rpoB allelic types were identified among these isolates, indicating considerable diversity among endospore-forming spoilage organisms present in fluid milk systems. Of the 92 allelic types identified, 19 were isolated from samples collected from both processing plants. The same rpoB allelic types were frequently identified in paired raw milk and packaged product samples, indicating that Bacillus and Paenibacillus spp. can enter dairy processing systems through raw milk. Certain subtypes were found exclusively in pasteurized samples, including those that were temporally independent, suggesting the possibility of in-plant sources for these spoilage organisms, including through the persistence of selected subtypes in processing plants. Development of effective control strategies for the diverse array of psychrotolerant endospore-forming organisms that currently limit the shelf lives of high-temperature short-time fluid milk products will require comprehensive, integrated efforts along the entire milk processing continuum.

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ELEMEN KLASTER INDUSTRI PENGOLAHAN SUSU DI DAERAH ISTIMEWA YOGYAKARTA

Buletin Peternakan ◽

10.21059/buletinpeternak.v39i1.6161 ◽

2015 ◽

Vol 39 (1) ◽

pp. 64

Author(s):

Nur Laili Marufah ◽

Tri Djoko Wisnumurti ◽

Budi Guntoro

Keyword(s):

Value Chain ◽

Local Economic Development ◽

Milk Powder ◽

Goat Milk ◽

Secondary Data ◽

Raw Milk ◽

Primary Data ◽

Milk Product ◽

Coffee Shop ◽

Milk Processing

This research was conducted to study the elements and value chain of milk-processing cluster industry in Daerah Istimewa Yogyakarta. The respondent in this study consisted of cow and goats milk processing industry, dairy cooperative and related institution. The data consisted of primary data and secondary data. Primary data were collected through observation and interviews, while secondary data obtained from statistical data from Department of Industry, Trade and Cooperatives, Agricultural Service of Agriculture Department and LPPOM MUI DIY. Descriptive analysis were used in this study to analyzed the data. Respondent and locations were determined using purposive sampling methods lead to be analyse descriptively. The results showed that stakeholders involved as important elements of milkprocessing cluster industry were milk suppliers (farmer, dairy groups, and cooperative), core industry (small-medium scale processor of cow’s and goat milk), supporting industry (sugar, packaging and tools), supporting institution (bank, university, and government agencies), related industry (food chain, bakery, and coffee shop), and also buyers (retailer, distributor, end user or consumer). Their main products are pasteurized cow’s and goat milk, yoghurt of cow’s milk, and goat milk powder. The long chains to produce milk product since the raw milk have indicated some added values on economy and involvement of man powers leading to local economic development as well as of technology innovation or industry. It has been concluded that milk-processing cluster industry could be used as a locomotive for regional economics development. (Key words: Daerah Istimewa Yogyakarta, Elements, Milk-processing cluster industry, Regional economic development, Value chain)

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Quality of raw milks in three milk processing plants in Cordoba

Revista Colombiana de Ciencia Animal - RECIA ◽

10.24188/recia.v6.n1.2014.222 ◽

2014 ◽

Vol 6 (1) ◽

pp. 103 ◽

Cited By ~ 1

Author(s):

VIRGINIA RODRÍGUEZ, R. ◽

ALFONSO CALDERÓN R. ◽

OSCAR VERGARA G.

Keyword(s):

Physicochemical Parameters ◽

Microbiological Quality ◽

Raw Milk ◽

Fecal Coliforms ◽

Processing Plant ◽

Normal Range ◽

Dual Purpose ◽

Milk Processing ◽

Processing Plants

An important condition in dairy processing plant is to obtain materials of excellent physicochemical and microbiological quality to reduce public health risks. High counts of mesophilic show contamination and lack of good manipulation in milking and milk conservation. Coliforms are a demonstration of contamination with fecal material. The norms in Colombia establish the mesophilic count as standard of microbiological quality. The purpose of this study was to determine the physicochemical and microbiological quality and health of the udders, in raw milk from dual purpose farms, supplying three milk processing plants in Cordoba (Colombia). 149 raw milk samples were collected of tree processing plants in Cordoba department. Physicochemical parameters set out in Decree 616 of 2006 were determined and aerobic mesophilic, total coliforms, fecal coliforms, and somatic cell count were established too. The variables obtained were analyzed by descriptive statistics using SAS. The physicochemical parameters were within the normal range but averages of mesophilic and somatic cells counts were high, which allows conclude that the physicochemical quality is good, but there are shortcomings in the microbiological quality and in the udder health, and is on the farms devoted to milk production where must be implemented and certified excellent management and prevention practices.

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Prevalence, Types, and Geographical Distribution of Listeria monocytogenes from a Survey of Retail Queso Fresco and Associated Cheese Processing Plants and Dairy Farms in Sonora, Mexico†

Journal of Food Protection ◽

10.4315/0362-028x-70.11.2596 ◽

2007 ◽

Vol 70 (11) ◽

pp. 2596-2601 ◽

Cited By ~ 30

Author(s):

R. I. MORENO-ENRIQUEZ ◽

A. GARCIA-GALAZ ◽

E. ACEDO-FELIX ◽

H. GONZALEZ-RIOS ◽

J. E. CALL ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Environmental Samples ◽

Northern Region ◽

Pulsed Field Gel Electrophoresis ◽

Department Of Agriculture ◽

Retail Markets ◽

Processing Plants ◽

Contact Surfaces ◽

Inspection Service ◽

The U.S

In the first part of this study, samples were collected from farms, cheese processing plants (CPPs), and retail markets located in various geographical areas of Sonora, Mexico, over a 12-month period during the summer of 2004 and winter of 2005. Four (all Queso Fresco [QF] from retail markets) of 349 total samples tested positive for Listeria monocytogenes (Lm). Of these four positive samples, three were collected in the northern region and one in the southern region of Sonora. Additionally, two were collected during the winter months, and two were collected during the summer months. For the second part of the study, a total of 39 samples from a farm, a CPP, and retail markets were collected and processed according to a combination of the Norma Oficial Mexicana NOM-143-SSA1-1995.10 method (NOM) and the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual method, and 27 samples from these same locations were collected and processed according to the U.S. Department of Agriculture Food Safety and Inspection Service method (USDA-FSIS). The NOM-FDA method recovered the pathogen from 6 (15%) of 39 samples (one cheese and five product contact surfaces), while the USDA-FSIS method recovered the pathogen from 5 (18.5%) of 27 samples (all product contact surfaces). In addition, the 40 isolates recovered from the 15 total samples that tested positive for Lm grouped into five distinct pulsotypes that were ca. 60% related, as determined by pulsed-field gel electrophoresis analysis. The results of this study confirmed a 3.4% prevalence of Lm in QF collected from retail markets located in Sonora and no appreciable difference in the effectiveness of either the NOM-FDA or USDA-FSIS method to recover the pathogen from cheese or environmental samples.

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Hygienic Conditions and Microbial Contamination in Six Ewe's-Milk-Processing Plants in Sardinia, Italy

Journal of Food Protection ◽

10.4315/0362-028x-60.3.283 ◽

1997 ◽

Vol 60 (3) ◽

pp. 283-287 ◽

Cited By ~ 18

Author(s):

SOFIA COSENTINO ◽

FRANCESCA PALMAS

Keyword(s):

Microbial Contamination ◽

Microbiological Quality ◽

Raw Milk ◽

Raw Material ◽

Processing Conditions ◽

Technological Parameters ◽

Milk Processing ◽

Processing Plants ◽

Ewe's Milk

In Sardinia, ewe's milk is almost exclusively used for cheese manufacture, and it is usually processed in small dairies which do not have sufficient technical and scientific knowledge for largescale controlled production. This study was carried out to identify the sources of contamination and the kinds of contaminating microorganisms present in six ewe's milk processing plants in Sardinia. Samples were collected during production hours three times over a period of 6 months. Raw milk, heat-treated milk, curd, 30-day-old cheese, lactic culture, rennet, and water used in processing lines were analyzed and the microbial contamination of air and surfaces was evaluated. Total mesophilic aerobic counts, coliforms, Escherichia coli, gram-negative psychrotrophs, Staphylococcus aureus, Salmonella spp., Listeria spp., yeasts, and molds were determined. Our survey confirmed that the production offood of high microbiological quality is strictly dependent on the microbiological quality of the raw material, optimization of the parameters for the heat treatment, water of potable quality, well-defined cleaning and disinfection procedures, and properly hygienic processing conditions. In fact, only plants characterized by raw milk and rennet of acceptable quality, generally clean work surfaces, and low microbial counts in the air of working areas made finished products of high microbiological quality. Standardization of technological parameters and achievement of properly hygienic processing conditions will help minimize the risk of developing food-safety problems, in compliance with public health regulatory requirements. These actions would help guarantee an adequate quality of Sardinian ewe's milk cheeses and might also lead to access to the international market.

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Tracking of Listeria monocytogenes in Smoked Fish Processing Plants†

Journal of Food Protection ◽

10.4315/0362-028x-67.2.328 ◽

2004 ◽

Vol 67 (2) ◽

pp. 328-341 ◽

Cited By ~ 92

Author(s):

JOANNE THIMOTHE ◽

KENDRA KERR NIGHTINGALE ◽

KEN GALL ◽

VIRGINIA N. SCOTT ◽

MARTIN WIEDMANN

Keyword(s):

Listeria Monocytogenes ◽

Environmental Samples ◽

Control Strategies ◽

Fish Processing ◽

Smoked Fish ◽

Plant Environment ◽

Fish Samples ◽

Processing Plants ◽

Raw Fish ◽

Contact Surfaces

Four smoked fish processing plants were used as a model system to characterize Listeria monocytogenes contamination patterns in ready-to-eat food production environments. Each of the four plants was sampled monthly for approximately 1 year. At each sampling, four to six raw fish and four to six finished product samples were collected from corresponding lots. In addition, 12 to 14 environmental sponge samples were collected several hours after the start of production at sites selected as being likely contamination sources. A total of 234 raw fish, 233 finished products, and 553 environmental samples were tested. Presumptive Listeria spp. were isolated from 16.7% of the raw fish samples, 9.0% of the finished product samples, and 27.3% of the environmental samples. L. monocytogenes was isolated from 3.8% of the raw fish samples (0 to 10%, depending on the plant), 1.3% of the finished product samples (0 to 3.3%), and 12.8% of the environmental samples (0 to 29.8%). Among the environmental samples, L. monocytogenes was found in 23.7% of the samples taken from drains, 4.8% of the samples taken from food contact surfaces, 10.4% of the samples taken from employee contact surfaces (aprons, hands, and door handles), and 12.3% of the samples taken from other nonfood contact surfaces. Listeria spp. were isolated from environmental samples in each of the four plants, whereas L. monocytogenes was not found in any of the environmental samples from one plant. Overall, the L. monocytogenes prevalence in the plant environment showed a statistically significant (P < 0.0001) positive relationship with the prevalence of this organism in finished product samples. Automated EcoRI ribotyping differentiated 15 ribotypes among the 83 L. monocytogenes isolates. For each of the three plants with L. monocytogenes–positive environmental samples, one or two ribotypes seemed to persist in the plant environment during the study period. In one plant, a specific L. monocytogenes ribotype represented 44% of the L. monocytogenes–positive environmental samples and was also responsible for one of the two finished product positives found in this plant. In another plant, a specific L. monocytogenes ribotype persisted in the raw fish handling area. However, this ribotype was never isolated from the finished product area in this plant, indicating that this operation has achieved effective separation of raw and finished product areas. Molecular subtyping methods can help identify plant-specific L. monocytogenes contamination routes and thus provide the knowledge needed to implement improved L. monocytogenes control strategies.

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Harmful biological agents in the working environment of dairy plant workers

Occupational Safety – Science and Practice ◽

10.5604/01.3001.0011.7568 ◽

2018 ◽

Vol 559 (4) ◽

pp. 8-11

Author(s):

Agata Stobnicka

Keyword(s):

Preventive Measures ◽

Raw Milk ◽

Biological Agents ◽

Working Environment ◽

Occupational Hazards ◽

Milk Processing ◽

Adverse Health Outcomes ◽

Home Based ◽

Processing Plants ◽

Dairy Plant

Occupational hazards for dairy plant workers include contact with bioaerosols emitted during the production process, contact with raw milk, or with animals in the case of small home-based milk processing plants. Dairy plant workers can be exposed to biological agents, such as bacteria, fungi and viruses, which are responsible for various diseases and adverse health outcomes. Therefore, reliable risk assessment and appropriate preventive measures are key to occupational hazard prevention among this group of workers.

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Listeria monocytogenes Contamination of Turkey Franks: Evaluation of a Production Facility

Journal of Food Protection ◽

10.4315/0362-028x-53.12.1015 ◽

1990 ◽

Vol 53 (12) ◽

pp. 1015-1019 ◽

Cited By ~ 68

Author(s):

JAY D. WENGER ◽

BALA SWAMINATHAN ◽

PEGGY S. HAYES ◽

STANLEY S. GREEN ◽

MARK PRATT ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Food Processing ◽

Environmental Samples ◽

Meat Products ◽

Conveyor Belt ◽

Most Probable Number ◽

Retail Outlet ◽

Probable Number ◽

Processing Plants ◽

Production Stages

A facility which produced turkey franks that had been microbiologically linked to a case of human listeriosis was evaluated to establish prevalence of contamination and identify potential points for intervention. Listeria monocytogenes was isolated from only two of 41 environmental samples obtained in the plant. Among production line product samples analyzed by the Centers for Disease Control, 0 to 8% of samples from the production stages before the peeler-conveyor belt apparatus were positive for the case strain of L. monocytogenes, whereas 12 of 14 (86%) samples collected from this apparatus were positive (p <0.001). The most probable number (MPN) of L. monocytogenes in finished product purchased from a retail outlet was less than 0.3 per gram; however, the opened package of franks from the case patient's refrigerator had an MPN of >1100 per gram. These data suggest that systematic culturing and analysis of products and production facilities may help identify appropriate interventions to reduce L. monocytogenes contamination in food processing plants and contribute to control of L. monocytogenes in ready-to-eat meat products.

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