The ability of the divalent cations magnesium, iron, calcium and manganese; yeast extract; pyruvate; catalase; and the carbohydrates glucose, lactose, sucrose, esculin, fructose, galactose, maltose, and mannose to facilitate repair of heat-injured Listeria monocytogenes and Listeria innocua was evaluated. Listeria populations were injured by heating at 56°C for 50 min. To determine the effects on repair, Trypticase soy broth (TSB) was supplemented with each medium component to be evaluated. Repair occurred to various degrees within 5 h in TSB supplemented with glucose, lactose, sucrose, yeast extract, pyruvate, or catalase. Chelex-exchanged TSB was supplemented with divalent cations; magnesium and iron cations were found to have a role in repair. Listeria repair broth (LRB) was formulated by utilizing the components that had the greatest impact upon repair. When incubated in LRB, heat-injured Listeria cells completed repair in 5 h. After the repair, acriflavin, nalidixic acid, and cycloheximide were added to LRB to yield final concentrations identical to those of the selective enrichment broths used in the procedures of the Food and Drug Administration and the U.S. Department of Agriculture. The efficacy of LRB in promoting repair and enrichment of heat-injured Listeria cells was compared with that of existing selective enrichment broths. Repair was not observed in the Food and Drug Administration enrichment broth, Listeria enrichment broth, or University of Vermont enrichment broth. The final Listeria populations after 24 h of incubation in selective enrichment media were 1.7 x 108 to 9.1 X 108 CFU/ml; populations in LRB consistently averaged 2.5 x 1011 to 8.2 x 1011 CFU/ml.

As a leading cause of death from a foodborne pathogen, Listeria monocytogenes continues to cause sporadic cases and outbreaks of illness. The most recent of these outbreaks in the United States involved consumption of hot dogs, with 101 cases of illness and 21 deaths reported to the Centers for Disease Control and Prevention for the years 1998–1999. Epidemiologic analysis determined that contamination levels in hot dogs were remarkably low (0.3 CFU [colony‐forming units] L monocytogenes serotype 4b/g). That same year, manufacturers of hot dogs and luncheon meats collectively recalled more than 500,000 pounds of product owing to possible Listeria contamination. This article, through focus on issues such as reexamination of zero‐tolerance policies, improvements in detection and enumeration procedures, the impact of epidemiologic innovations, and measures needed to further reduce the incidence of listeriosis will highlight why L monocytogenes remains a continuing challenge for the food industry.

Listeria monocytogenes strains 19111, 19113, 19115, F5027 and F5069 were grown in 11% nonfat milk solids, skim milk and whole milk at 4, 10, 22, and 37°C to determine the influence of temperature and milk composition on growth and thermal resistance. Milk composition affected cellular growth. The psychrotrophic growth of L. monocytogenes serotype 4b strains was enhanced in whole milk when compared to skim milk or 11% NFMS. This enhancement of psychrotrophic growth was not observed for serotype 1 or 3 strains. The stimulatory effect of whole milk on serotype 4b L. monocytogenes strains was most dramatic at 10°C where cells increased from 7.9 × 10° to 5.8 × 106 CFU/ml within 48 h. Milk composition did not affect the thermal resistance of L. monocytogenes. All strains used in this study had a D62.7°C value of 1.0 min or less, therefore, pasteurization as defined by current FDA guidelines should eliminate this organism from raw milk with a large margin of safety. Post-pasteurization contamination of dairy products with L. monocytogenes must be eliminated since the psychrotrophic nature of this organism ensures survival and proliferation during refrigerated storage.

This study was conducted to examine the fate of Escherichia coli O157:H7 during the manufacture and aging of Gouda and stirred-curd Cheddar cheeses made from raw milk. Cheeses were manufactured from unpasteurized milk experimentally contaminated with one of three strains of E. coli O157:H7 at an approximate population level of 20 CFU/ml. Samples of milk, whey, curd, and cheese were collected for enumeration of bacteria throughout the manufacturing and aging process. Overall, bacterial counts in both cheese types increased almost 10-fold from initial inoculation levels in milk to approximately 145 CFU/g found in cheeses on day 1. From this point, counts dropped significantly over 60 days to mean levels of 25 and 5 CFU/g in Cheddar and Gouda, respectively. Levels of E. coli O157:H7 fell and stayed below 5 CFU/g after an average of 94 and 108 days in Gouda and Cheddar, respectively, yet remained detectable after selective enrichment for more than 270 days in both cheese types. Changes in pathogen levels observed throughout manufacture and aging did not significantly differ by cheese type. In agreement with results of previous studies, our results suggest that the 60-day aging requirement alone is insufficient to completely eliminate levels of viable E. coli O157:H7 in Gouda or stirred-curd Cheddar cheese manufactured from raw milk contaminated with low levels of this pathogen.

Background People with multiple sclerosis (MS) require complex care throughout life. Canadians with MS are high users of health‐care services, yet still report unmet health‐care needs and low satisfaction with services received. Objective This study aimed to investigate the health‐care access experiences of Ontarians with MS as they manage their condition. Design and Participants Interpretive description guided data collection and analysis. Forty‐eight people living across seven communities participated. Thirty‐eight participated in one of five focus groups; the remaining 10 participated in an individual semi‐structured interview. Results Participants described the experience of accessing care as a decisional process, guided by a form of cost‐benefit analysis. The process determined whether seeking conventional health‐care services ‘is worth it’. Most participants felt that the energy and resources required to access the health‐care system outweighed their expected outcomes, based on past experiences. Participants who did not see the benefit of care seeking turned to self‐treatment, use of complementary and alternative services, and engaged in patterns of health‐care avoidance until a crisis arose. Discussion and Conclusion Findings suggest that a renewed effort to promote patient‐centred care and a biopsychosocial approach may improve the health‐care access experiences of persons with MS and reduce service avoidance.