scholarly journals Host Ranges of Listeria-Specific Bacteriophages from the Turkey Processing Plant Environment in the United States

2008 ◽  
Vol 74 (21) ◽  
pp. 6623-6630 ◽  
Author(s):  
Jae-Won Kim ◽  
Robin M. Siletzky ◽  
Sophia Kathariou
Keyword(s):  
United States ◽  
Host Range ◽  
Environmental Samples ◽  
The United States ◽  
Host Cells ◽  
Processing Plant ◽  
Wide Host Range ◽  
Plant Environment ◽  
Processing Plants ◽  
Serotype 4B

ABSTRACT Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants.

scholarly journals Temperature-Dependent Phage Resistance of Listeria monocytogenes Epidemic Clone II

2009 ◽  
Vol 75 (8) ◽  
pp. 2433-2438 ◽  
Author(s):  
Jae-Won Kim ◽  
Sophia Kathariou
Keyword(s):  
Listeria Monocytogenes ◽  
The United States ◽  
Phage Resistance ◽  
Processing Plant ◽  
Broad Host Range ◽  
Temperature Dependent ◽  
Cadmium Resistance ◽  
Epidemic Clone ◽  
Plant Environment ◽  
Serotype 4B

ABSTRACT Listeria monocytogenes epidemic clone II (ECII) has been responsible for two multistate outbreaks in the United States in 1998-1999 and in 2002, in which contaminated ready-to-eat meat products (hot dogs and turkey deli meats, respectively) were implicated. However, ecological adaptations of ECII strains in the food-processing plant environment remain unidentified. In this study, we found that broad-host-range phages, including phages isolated from the processing plant environment, produced plaques on ECII strains grown at 37°C but not when the bacteria were grown at lower temperatures (30°C or below). ECII strains grown at lower temperatures were resistant to phage regardless of the temperature during infection and subsequent incubation. In contrast, the phage susceptibility of all other tested strains of serotype 4b (including epidemic clone I) and of strains of other serotypes and Listeria species was independent of the growth temperature of the bacteria. This temperature-dependent phage susceptibility of ECII bacteria was consistently observed with all surveyed ECII strains from outbreaks or from processing plants, regardless of the presence or absence of cadmium resistance plasmids. Phages adsorbed similarly on ECII bacteria grown at 25°C and at 37°C, suggesting that resistance of ECII strains grown at 25°C was not due to failure of the phage to adsorb. Even though the underlying mechanisms remain to be elucidated, temperature-dependent phage resistance may represent an important ecological adaptation of L. monocytogenes ECII in processed, cold-stored foods and in the processing plant environment, where relatively low temperatures prevail.

Longitudinal Studies on Listeria in Smoked Fish Plants: Impact of Intervention Strategies on Contamination Patterns

2004 ◽  
Vol 67 (11) ◽  
pp. 2500-2514 ◽  
Author(s):  
VICTORIA R. LAPPI ◽  
JOANNE THIMOTHE ◽  
KENDRA KERR NIGHTINGALE ◽  
KENNETH GALL ◽  
VIRGINIA N. SCOTT ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Control Strategies ◽  
Intervention Strategies ◽  
Raw Material ◽  
Processing Plant ◽  
Smoked Fish ◽  
Plant Environment ◽  
Before And After ◽  
Processing Plants ◽  
The Impact

Four ready-to-eat smoked fish plants were monitored for 2 years to study Listeria contamination patterns and the impact of plant-specific Listeria control strategies, including employee training and targeted sanitation procedures, on Listeria contamination patterns. Samples from the processing plant environment and from raw and finished product were collected monthly and tested for Listeria spp. and Listeria monocytogenes. Before implementation of intervention strategies, 19.2% of raw product samples (n = 276), 8.7% of finished product samples (n = 275), and 26.1% of environmental samples (n = 617) tested positive for Listeria spp. During and after implementation of Listeria control strategies, 19.0% of raw product samples (n = 242), 7.0% of finished product samples (n = 244), and 19.5% of environmental samples (n = 527) were positive for Listeria spp. In one of the four fish plants (plant 4), no environmental samples were positive for L. monocytogenes, and this plant was thus excluded from statistical analyses. Based on data pooled from plants 1, 2, and 3, environmental Listeria spp. prevalence was significantly lower (P < 0.05) for nonfood contact surfaces and the finished product area and for the overall core environmental samples after implementation of control strategies. Listeria prevalence for floor drains was similar before and after implementation of controls (49.6 and 54.2%, respectively). Regression analysis revealed a significant positive relationship (P < 0.05) between L. monocytogenes prevalence in the environment and in finished products before implementation of control strategies; however, this relationship was absolved by implementation of Listeria control strategies. Molecular subtyping (EcoRI ribotyping) revealed that specific L. monocytogenes ribotypes persisted in three processing plants over time. These persistent ribotypes were responsible for all six finished product contamination events detected in plant 1. Ribotype data also indicated that incoming raw material is only rarely a direct source of finished product contamination. While these data indicate that plant-specific Listeria control strategies can reduce cross-contamination and prevalence of Listeria spp. and L. monocytogenes in the plant environment, elimination of persistent L. monocytogenes strains remains a considerable challenge.

scholarly journals Genetic Listeria monocytogenes Types in the Pork Processing Plant Environment: From Occasional Introduction to Plausible Persistence in Harborage Sites

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 717
Author(s):  
Niels Demaître ◽  
Geertrui Rasschaert ◽  
Lieven De Zutter ◽  
Annemie Geeraerd ◽  
Koen De Reu
Keyword(s):  
Genetic Diversity ◽  
Environmental Samples ◽  
Genetic Characterization ◽  
Processing Plant ◽  
Pfge Analysis ◽  
Food Contact ◽  
Plant Environment ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Cleaning And Disinfection

The purpose of this study was to investigate the L. monocytogenes occurrence and genetic diversity in three Belgian pork cutting plants. We specifically aim to identify harborage sites and niche locations where this pathogen might occur. A total of 868 samples were taken from a large diversity of food and non-food contact surfaces after cleaning and disinfection (C&D) and during processing. A total of 13% (110/868) of environmental samples tested positive for L. monocytogenes. When looking in more detail, zone 3 non-food contact surfaces were contaminated more often (26%; 72/278) at typical harborage sites, such as floors, drains, and cleaning materials. Food contact surfaces (zone 1) were less frequently contaminated (6%; 25/436), also after C&D. PFGE analysis exhibited low genetic heterogeneity, revealing 11 assigned clonal complexes (CC), four of which (CC8, CC9, CC31, and CC121) were predominant and widespread. Our data suggest (i) the occasional introduction and repeated contamination and/or (ii) the establishment of some persistent meat-adapted clones in all cutting plants. Further, we highlight the importance of well-designed extensive sampling programs combined with genetic characterization to help these facilities take corrective actions to prevent transfer of this pathogen from the environment to the meat.

Food Safety: Problems of the Past and Perspectives of the Future1

1982 ◽  
Vol 45 (7) ◽  
pp. 658-660 ◽  
Author(s):  
E. M. FOSTER
Keyword(s):  
United States ◽  
Food Poisoning ◽  
Food Service ◽  
The United States ◽  
Red Tides ◽  
Animal Products ◽  
The Past ◽  
Processing Plants ◽  
Market Areas ◽  
Bacterial Food

Historically, most bacterial food poisoning in the United States is associated with mishandling, either in the home or in the food service establishment. Outbreaks traceable to errors in processing plants are rare. When they do occur they are often associated with changes in processing or packaging technology whose effect is not determined before the product is on the market. Areas of future concern that need research include (1) a better understanding of the mycotoxins; (2) how to minimize Salmonella contamination in animal products; (3) how to prevent, or at least predict, red tides; (4) better bactericidal agents that can be applied to foods; (5) an understanding of the nature and significance of mutagenic agents that are produced in foods during cooking.

A revision of species of the genus Haematoloechus Looss, 1899 (Trematoda: Haematoloechidae) from Canada and the United States

1981 ◽  
Vol 59 (9) ◽  
pp. 1836-1846 ◽  
Author(s):  
Murray J. Kennedy
Keyword(s):  
United States ◽  
Host Range ◽  
Geographical Variation ◽  
Rana Catesbeiana ◽  
Field Studies ◽  
The United States ◽  
Valid Species ◽  
Narrow Host Range ◽  
Species Groups ◽  
Degree Of Maturity

Previous experimental and field studies have shown that variations within the genus Haematoloechus may result from differences in age and degree of maturity, extent of crowding, species of host, and other factors.Based on these observations, only 6 of the 15 previously known species from Canada and the United States are considered valid. The valid species and their synonyms are as follows: Haematoloechus longiplexus Stafford, 1902; H. breviplexus Stafford, 1902; H. varioplexus Stafford, 1902 (= H. parviplexus, = H. buttensis, = H. similiplexus, = H. floedae, and H. uniplexus); H. kernensis Ingles, 1932 (= H. tumidus); H. medioplexus Stafford, 1902; and H. complexus (Seely, 1906) (= H. coloradensis, = H. confusus, = H. oxyorchis).The existence of three species groups is hypothesized. Haematoloechus longiplexus and H. breviplexus constitute one group, characterized by little geographical variation and a narrow host range. They are typically parasites of Rana catesbeiana and R. clamitans. Haematoloechus varioplexus and H. kernensis constitute the second group. These species have a wider host range and greater variation in characters purported to be specific differences. The third group includes those lung flukes which do not contain extracaecal loops (H. medioplexus and H. complexus). Of these, only H. medioplexus had little geographical variation and was found to occur in a single frog host.

Prevalence, Enumeration, and Antimicrobial Agent Resistance of Clostridium difficile in Cattle at Harvest in the United States

2011 ◽  
Vol 74 (10) ◽  
pp. 1618-1624 ◽  
Author(s):  
ALEXANDER RODRIGUEZ-PALACIOS ◽  
MOHAMMAD KOOHMARAIE ◽  
JEFFREY T. LeJEUNE
Keyword(s):  
United States ◽  
Clostridium Difficile ◽  
Antimicrobial Agents ◽  
Food Contamination ◽  
Intestinal Bacteria ◽  
The United States ◽  
Cross Sectional ◽  
Fecal Shedding ◽  
Processing Plants ◽  
Ribotype 078

To assess the potential for food contamination with Clostridium difficile from food animals, we conducted a cross-sectional fecal prevalence study in 944 randomly selected cattle harvested at seven commercial meat processing plants, representing four distant regions (median distance of 1,500 km) of the United States. In all, 944 animals were sampled in the summer of 2008. C. difficile was isolated from 1.8% (17 of 944) of cattle, with median fecal shedding concentration of 2.2 log CFU/g (range = 1.6 to 4.8, 95% confidence interval = 1.6, 4.3). Toxigenic C. difficile isolates were recovered from only four (0.4%) cattle. One of these isolates was emerging PCR ribotype 078/toxinotype V. The remaining toxigenic isolates were toxinotype 0, one of which was an isolate with resistance to linezolid, clindamycin, and moxifloxacin (by the E-test). All isolates were susceptible to vancomycin, metronidazole, and tigecycline, but the MICs against linezolid were as high as the highest reported values for human-derived isolates. The source of the linezolid-clindamycin-moxifloxacin resistance in a toxigenic C. difficile isolate from cattle is uncertain. However, since the use of these three antimicrobial agents in cattle is not allowed in North America, it is possible that resistance originated from an environmental source, from other species where those antimicrobial agents are used, or transferred from other intestinal bacteria. This study confirms that commercial cattle can carry epidemiologically relevant C. difficile strains at the time of harvest, but the prevalence at the time they enter the food chain is low.

Salmonella Contamination during Production of Cantaloupe: A Binational Study

2004 ◽  
Vol 67 (4) ◽  
pp. 713-720 ◽  
Author(s):  
A. CASTILLO ◽  
I. MERCADO ◽  
L. M. LUCIA ◽  
Y. MARTÍNEZ-RUIZ ◽  
J. PONCE de LEÓN ◽  
...  
Keyword(s):  
United States ◽  
Water Samples ◽  
Environmental Samples ◽  
Rio Grande Valley ◽  
The United States ◽  
South Texas ◽  
Pcr Analysis ◽  
E Coli ◽  
Binational Study ◽  
Valley Area

Six cantaloupe farms and packing plants in South Texas (950 cantaloupe, 140 water, and 45 environmental samples), including the Rio Grande Valley area, and three farms in Colima State, Mexico (300 cantaloupe, 45 water, and 15 environmental samples), were sampled to evaluate cantaloupe contamination with Salmonella and Escherichia coli during production and processing. Samples collected from external surfaces of cantaloupes, water, and the environments of packing sheds on cantaloupe farms were examined for the presence of Salmonella and E. coli. Of a total of 1,735 samples collected, 31 (1.8%) tested positive for Salmonella. Fifteen Salmonella serotypes were isolated from samples collected in Texas, and nine from samples collected in Colima. Two serotypes (Poona and Oranienburg) that have been associated with three large Salmonella outbreaks in the United States and Canada linked to the consumption of contaminated cantaloupe were found in water samples collected at four farms (three from the United States). Susceptibility of Salmonella isolates to 10 antimicrobials was evaluated by disk diffusion. Eighty-eight percent of the isolates from the United States and Mexico were pansusceptible to the antimicrobials tested; eight isolates from the United States demonstrated an intermediate susceptibility to streptomycin and only two isolates were resistant to the same antimicrobial. From Mexico, four isolates showed an intermediate susceptibility to streptomycin and one isolate was resistant to nalidixic acid and streptomycin. Repetitive sequence-based PCR analysis of Salmonella isolates helped to trace potential sources of Salmonella contamination in source water and in subsequent water samples obtained after the filtration systems of U.S. and Mexican cantaloupe farms. No differences could be seen between the levels of Salmonella contamination in melons from both countries.

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