4,041 research outputs found
Quantitative risk assessment of Listeria monocytogenes in traditional Minas cheeses: the cases of artisanal semi-hard and fresh soft cheeses
No full textThis study estimated the risk of listeriosis from Brazilian cheese consumption using quantitative microbial risk assessment (QMRA). Risks associated to consumption of two cheese types were assessed: artisanal ripened semi-hard cheese (produced with raw milk) and refrigerated fresh soft cheese (produced with pasteurized milk). The semi-hard cheese model predicted Listeria monocytogenes growth or decline during ripening, while the soft cheese model predicted pathogen growth during refrigerated storage. Semi-hard cheese modeling scenarios considered L. monocytogenes starting concentration from -2.4 to 6 log CFU/mL in raw milk and three ripening times (4, 22 and 60 days). Soft cheese modeling scenarios considered L. monocytogenes starting concentration from -2.4 to 4 log CFU/mL in milk. The inclusion of anti-listerial lactic acid bacteria (LAB) in cheeses was also examined. Risk of listeriosis due to consumption of soft cheese was 6,000 and 190 times greater than that of semi-hard cheese, for general and vulnerable populations, respectively. Aging semi-hard cheese reduced risk, and risk was influenced by L. monocytogenes starting concentration. Aging cheese with inhibitory LAB for 22 days reduced risk over 4 million-fold when L. monocytogenes was assumed to be 6 log CFU/mL in raw milk. The inclusion of inhibitory LAB also reduced risk of listeriosis due to soft cheese consumption, but not as much as for semi-hard cheese. QMRA results predicted that consumption of contaminated cheeses can carry a high risk of listeriosis, especially for vulnerable populations. Scenario analyses indicated that aging of semi-hard cheese and inclusion of antimicrobial LAB mix in semi-hard and soft cheeses are effective risk mitigation measures.Peer reviewe
Quantifying the Effect of Water Temperature, Soap Volume, Lather Time, and Antimicrobial Soap as a Factor in the Removal of Escherichia coli ATCC 11229 from Hands
No full textThe handwashing literature, while extensive, often contains conflicting data and key variables are understudied or not studied at all. Some handwashing recommendations are made without scientific support, and there is limited agreement between recommendations. The influence of key variables including soap volume, lather time, water temperature, and product formulation on hand wash efficacy was investigated. Baseline conditions were 1 mL of a bland (nonantimicrobial) soap, a 5 s lather time, and 38 °C (100 °F) water temperature. A nonpathogenic strain of Escherichia coli ATCC 11229 served as the challenge microorganism. Twenty volunteers (10 men, 10 women) participated in the study and each test condition had 20 replicates. An antimicrobial soap formulation (1% chloroxylenol, or PCMX) was not significantly different from the bland soap at removing E. coli under a variety of test conditions. Overall, the antimicrobial soap used in this study had a mean 1.94 log CFU reduction (range 1.83 to 2.10 mean log reduction), and bland soap had a mean 2.22 log CFU reduction (range 1.91 to 2.54 mean log CFU reduction). Overall, lather time did significantly influence efficacy in one scenario, in which a 0.5 greater log reduction was observed for a 20 s with bland soap compared to the baseline wash (P=0.020). Water temperature as high as 38°C (100°F) vs. a low of 15°C (60°F) did not have a significant effect on the reduction of bacteria during hand washing, however this resulted in an energy usage difference between the temperatures. No significant differences were observed between mean log reductions of men and women (men= 2.08 mean log reduction, women=2.08 mean log reduction, P=0.988). A large part of the variability in the data observed was between the volunteers. Understanding what behaviors and human factors influence hand washes the most may help future studies find which techniques can optimize the effectiveness of a hand wash.Peer reviewe
Surfactant Concentration and Type Affects the Removal of Escherichia coli from Pig Skin During a Simulated Handwash
No full textThe effect of surfactant type and concentration on a bland soap formulations ability to remove bacteria from hands remains largely unstudied. Several combinations of surfactants and water were combined to test bacterial removal efficacy using a handwashing device (two pieces of pig skin and a mechanical motor) to simulate a handwash. A nalidixic acid resistant, non-pathogenic strain of Escherichia coli (ATCC 11229) was used. Two anionic surfactants, sodium lauryl sulfate and sodium stearoyl lactylate, and two nonionic surfactants, poloxamer 407 and sorbitan monostearate, each in concentrations of 2%, 5%, and 10% were studied. A slight positive (r2=0.17) but significant (p=0.03) correlation was observed between hydrophile-lipophile balance value and mean log reduction. No correlation was observed between pH of the treatment solution and the mean log reduction (r2=0.05, p=0.25). A 10% sodium lauryl sulfate mixture showed the highest log reduction (x̄= 1.1 log cfu reduction, SD=0.54), and was the only treatment significantly different from washing with water (p=0.0005). There was a correlation between increasing surfactant concentrations above the critical micelle concentration, and mean microbial reduction (r2=0.62, p=0.001).Peer reviewe
Eccritotarsus corcovadensis Carvalho and Schaffner
No full textEccritotarsus corcovadensis Carvalho and Schaffner (Fig. 22) Eccritotarsus corcovadensis Carvalho and Schaffner, 1986: 309 (orig. descrip.). Diagnosis. Color uniformly yellowish white; hemelytra white, hyaline; membrane clear. Length 4.22 mm. Host. Unknown. Distribution. Brazil (Rio de Janeiro) (Carvalho and Schaffner, 1986). Minas Gerais represents a new Brazilian state record. Minas Gerais specimens examined. 2 ɗɗ, Viçosa, 13 Sept. 1986, 5 Mar. 1987, P. S. Fiuza Ferreira (UFVB).Published as part of Ferreira, Paulo Sergio Fiuza & Henry, Thomas J., 2011, Synopsis and keys to the tribes, genera, and species of Miridae (Hemiptera: Heteroptera) of Minas Gerais, Brazil Part I: Bryocorinae, pp. 1-41 in Zootaxa 2920 on page 16, DOI: 10.5281/zenodo.27791
The Influence of Soap Characteristics and Food Service Facility Type on the Degree of Bacterial Contamination of Open, Refillable Bulk Soaps
No full textConcern has been raised regarding the public health risks from refillable-bulk soap dispensers because they provide an environment for potentially pathogenic bacteria to grow. This study surveyed the microbial quality of open refillable bulk soap in four different food establishment types in three states. Two hundred and ninety-six samples of bulk soap were collected from foodservice establishments in Arizona, New Jersey, and Ohio. Samples were tested for total heterotrophic viable bacteria, Pseudomonas, coliforms and Escherichia coli and Salmonella. Bacteria were screened for antibiotic resistance. The pH, solids content and water activity of all soap samples was measured. Samples were assayed for the presence of the common antibacterial agents triclosan and parachlorometaxylenol. More than 85% of the soap samples tested contained no detectable microorganisms, but when a sample contained any detectable microorganisms, it was most likely contaminated at a very high level (~7 log CFU/ml). Microorganisms detected in contaminated soap included Klebsiella oxytoca, Serratia liquefaciens, Shigella sonnei, Enterobacter gergoviae, Serratia odorifera and Enterobacter cloacae. Twenty-three samples contain antibiotic resistant organisms, some of which were resistant to two or more antibiotics. Every sample containing less than 4% solids had some detectable level of bacteria, while no samples with greater than 14% solids had detectable bacteria. This finding suggests dilution and/or low-cost formulations as a cause. There was a statistically significant difference (p=0.0035) between the fraction of bacteria positive samples with no detected antimicrobial (17%) and those containing an antimicrobial (7%). Fast food operations and grocery stores were more likely to have detectable bacteria in bulk soap samples compared to convenience stores (p<0.05). Our findings underscore the risk to public health from use of refillable- bulk soap dispensers in foodservice establishments.Peer reviewe
Quantification of transfer of Salmonella from citrus fruits to peel, edible portion, and gloved hands during hand peeling
No full textAlthough studies have quantified bacterial transfer between hands and various materials, cross-contamination between the surface of fresh citrus fruit and the edible portions during hand peeling has not been reported. This study quantifies transfer of Salmonella to the edible portion of citrus fruit from a contaminated peel during hand peeling. Citrus fruits used for this study were Citrus sinensis (sweet orange) cultivars ‘Valencia’ and ‘Navel’ and C. unshiu (Satsuma mandarins), C. reticulata × C. paradisi (‘Minneola’ tangelo or ‘Honeybell’) and C. paradise (grapefruit) cultivar ‘Marsh'. An avirulent Salmonella Typhimurium LT - 2 (ATCC 700720) resistant to rifampicin was used for all experiments. The inoculum containing ~9 log CFU/ml (50 µl) was spot inoculated onto the equator, stem or styler of each fruit and allowed to dry for 24 h. Six volunteers put on single use latex gloves and peeled inoculated fruit. Peel, edible fruit portion and gloves were collected and enumerated separately. Three replicates of the study were performed where each volunteer peeled 2 inoculated fruit of each variety (n=36 fruit per variety).
Cross-contamination from contaminated surface of citrus fruits to edible portion or gloved hands during peeling was affected by inoculation sites. Average Salmonella transfer to the edible portion ranged from 0.16 % (Valencia inoculated at the equator) to 5.41 % (Navel inoculated at the stem). Average Salmonella transfer to gloved hands ranged from 0.41 % (Grapefruit inoculated at the stem) to 8.97 % (Navel inoculated at the stem). Most Salmonella remained on the peel of citrus fruits. The average level of Salmonella remaining on the peel ranged from 5.37% (Minneola inoculated at the equator) to 66.3% (Satsuma inoculated at the styler). When grapefruit was inoculated, the Salmonella that remained on the peel showed a bimodal pattern where some individuals left almost all Salmonella on the peel, while others left substantially less.
Foodborne outbreaks associated with fresh produce have increased worldwide as consumption of fresh produce has also increased (3, 11, 16, 20, 27). While no outbreaks have been directly linked to whole fresh citrus fruit at this time, unpasteurized orange juice has been implicated in several outbreaks caused by Salmonella, Enterotoxigenic E. coli, Shigella, hepatitis A virus, and Norovirus (6, 8, 14, 18). The majority of outbreaks involving fruit and fruit juice have been attributed to pathogens contaminating the outer skin or rind, although the peel or rind of many fruits is discarded by the consumer and not eaten (11, 12, 25).
The FDA Food Safety Modernization Act (FSMA) includes fresh produce safety in its scope and focuses on preventing contamination during the production and harvesting of fresh fruits and vegetables (10). However, fresh produce including fresh citrus fruits can become contaminated at numerous points during transport, distribution, retailing and food preparation in the kitchen environment as well as production and harvesting (5, 16, 23, 27).
Cross-contamination from the surface of fresh produce to edible portions during cutting, slicing, or peeling can occur if the outer skin or rind of fresh produce is contaminated by pathogens (12, 18, 20, 25-27). Bacterial transfer from the skin to the edible flesh has been shown to occur during cutting of tomato and cantaloupes, both of which have implicated as the source of infection in some outbreaks (4, 12, 26). The surface of fresh citrus fruit has also been a source of pathogens, which can be transmitted to the juice during squeezing or peeling. Martinez-Gonzales et al. (17) reported that cross-contamination from inoculated fresh orange skin to utensils used in orange juice squeezing occurred, which subsequently resulted in bacterial transfer from contaminated utensils to squeezed orange juice.
Although studies have been conducted to determine the various factors that influence the bacterial transfer between hands and various surface materials (7, 15, 19), cross-contamination between the surface of fresh citrus fruit and the edible portions during hand peeling has not yet been reported. While a knife or citrus peeler might be used in commercial setting, this study was undertaken to quantify transfer of Salmonella to the edible portion of citrus fruit from a contaminated peel that can occur during hand peeling of a single fruit, as might occur in the home. Transfer rates were determined between various inoculation locations on the citrus fruits to the edible portion and gloved hands.Peer reviewe
Eccritotarsus curtipilis Carvalho & Schaffner 1986
No full textEccritotarsus curtipilis Carvalho & Schaffner, 1986 (Fig. 14) Eccritotarsus curtipilis Carvalho & Schaffner, 1986a: 310 (original description). Material examined. COLOMBIA. Risaralda: 1 ♂, SFF Otún Quimbaya, Urapanera, 1960 m, 4º44’N, 75º35’W, Malaise trap, 08–28.v.2003 (G. López) (IAVH-E-164652). Diagnosis. Body black and white. Head in dorsal view, antennal segments I (except base) and II, propleural areas anterior and posterior to the coxal cleft, xyphus and apex of cuneus black. Clavus dark brown to black; lateral margin with small median white spot. Corium with an irregular spot extending to the clavus or both clavus and embolium. Embolium with lateral margin predominantly black. Body length 3.48 mm. Associated/host plants. Unknown. Distribution. Colombia (Cundinamarca) (Carvalho & Schaffner 1986a); new department record: Risaralda. Comments. The median white spot on the lateral margin of clavus is important for this species identification and requires careful examination due to its small size.Published as part of Alvarez-Zapata, Alejandra, Ferreira, Paulo S. F. & Serna, Francisco, 2022, A taxonomic synopsis of the Eccritotarsini (Hemiptera: Heteroptera: Miridae Bryocorinae) of Colombia, pp. 101-151 in Zootaxa 5178 (2) on page 122, DOI: 10.11646/zootaxa.5178.2.1, http://zenodo.org/record/702216
Farm to Fork Quantitative Microbial Risk Assessment for Norovirus on Frozen Strawberries
No full textFoodborne illness outbreaks have been increasingly linked to the consumption of fresh and frozen berries that were contaminated with pathogenic viruses, such as human norovirus (NoV). Contamination of berries is assumed to take place at harvest by the use of contaminated water for pesticide dilution, irrigation water source or by shedding berry pickers in the field. A quantitative microbial risk assessment simulation model was built to replicate the largest known NoV outbreak which sickened about 11,000 people over a 3-week period. The outbreak occurred in Germany in 2012 when contaminated frozen strawberries were served at nearly 400 schools and daycare centers. The risk model explicitly assumed that all contamination would arise from NoV contamination of surface water used for pesticide dilution. Input data was collected from the published literature, observational studies and assumptions. The model starts with contamination of the berries in the field, and proceeds through transportation to processing facility, washing, sanitizing, freezing, frozen transport to cargo ship, transport view of cargo ship, transport to distribution center, frozen storage at the distribution center, transport to the catering facility, food service preparation and consumption, dose response, and predicted illnesses. A total of 21 scenarios were chosen to evaluate the impact of model parameters on the number of illness associated with NoV contamination of berries. Scenarios evaluated include the initial level of NoV in surface water, the effect of seasonality on the prevalence of NoV in surface water, the strength of the pesticide used, the volume of water used to dilute the pesticide, temperature during transportation to processing facility, washing and sanitizing conditions at processing facility and preparation (heat-treatment) of berries prior to consumption. Scenarios were compared via the Factor Sensitivity technique where the logarithm of the ratio of mean illnesses was used to compare different assumptions. The input that had the greatest effect on increasing in the number of illnesses was a high NoV concentration in the water (8 log Genome Copies/L) when compared to the baseline scenario with resulting mean illnesses of 7,964 illnesses and ~2 illnesses, respectively. This assumption about the concentration of virus in the pesticide makeup water was the only variable capable of producing an outbreak similar to that observed in Germany in 2012. Heat-treatment of the berries, use of a pesticide with strong antiviral effect, and assumption about the virus concentration in the pesticide make-up water had the largest impact on decreasing illnesses.Peer reviewe
History and Philosophy of Gene Environment Interaction
No full textDr. Kenneth Schaffner gave a brief introduction to the symposium topics. He began with a history of the thinking on gene-environment interactions and described the ensuing controversies. He cited the lack of a consensus theory of the environment and then described some methodological and technological advances in the studies of gene-environment interactions.

To watch Dr. Schaffner’s presentation, please see the Panel 1 "Google Video posting.":http://video.google.com/videoplay?docid=-3097337289947323438&hl=e
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