ASSESSMENT OF LUNG CANCER RISK REDUCTION BEFORE AND AFTER ADOPTION OF A RADON RESISTANT NEW CONSTRUCTION (RRNC) BUILDING CODE STANDARD IN AMITY TOWNSHIP, PA

Radon 222 (222Rn) is an element found in the soil surrounding many homes in the United States. It is formed during the natural radioactive decay of uranium. Radon gas moves into homes through cracks or holes in the foundation and can then be inhaled by the home residents. Inhaled radon is the second leading cause of lung cancer after smoking and is the leading cause in non-smokers. Radon-Resistant New Construction (RRNC) reduces residential radon exposure and reduces the risk of developing lung cancer. Several townships and municipalities in Pennsylvania have adopted ordinances that require new houses to be built using RRNC. To evaluate the effectiveness of RRNC in reducing radon-related lung cancer risk, residential radon concentrations were compared in homes with and without RRNC in a Pennsylvania township that has adopted the RRNC statue into their building codes. This study utilizes a risk-based decision framework to assess the lung cancer risk reduction in Amity Township, PA after adoption of a RRNC standard. The work primarily uses data on residential radon measurements that have been compiled by the Pennsylvania Department of Environmental Protection (PADEP). These measurements are reported to the PADEP by certified testers and homeowners. The results from the initial analysis on the radon concentrations will be used in a peer-reviewed lung cancer risk model to examine the reduction in risk for residents of RRNC homes versus non-RRNC homes. This work also uses publicly available measurable characteristics of health indicators such as lung cancer incidence and mortality collected from and/or about Amity Township, PA. Because the smoking rates were not available down to the township level, the smoking rates of Berks County, PA (where Amity Township is located) will be utilized. The health and economic benefits of adopting an RRNC standard will also be reviewed as part of the decision process

Effect of Acid Adaptation on the Thermal Inactivation of Listeria monocytogenes in Heating Menstrua Having Various Combinations of pH and Water Activities

The impact of prior growth and food matrix conditions on thermal resistance of <i>L. monocytogenes</i>, a causative agent of the foodborne illness listeriosis, was evaluated in this study. In an initial study ( Main Study #1), acid induced and non-induced cells of thirteen strains of <i>Listeria monocytogenes</i> were placed into two heating menstrua: pH 3.0, water activity (Aw) 0.987 and pH 7.0, Aw 0.970. In twelve out of twenty-six combinations, non-induced cells were more heat resistant than induced cells. <i>L. monocytogenes</i> strain #201, in a follow-up study ( Main Study #2) using a factorial design to test additional combinations of water activity and pH heating menstrua, non-acid-induced cells generally were more heat resistant than acid-induced cells although the acid-induced cells showed greater thermal resistance in the heating menstrua having the lowest pH values. An increase in thermal resistance could lead to underestimation of treatments necessary to eliminate potential contamination by <i>L. monocytogenes</i>

Detergent and sanitizer stresses decrease the thermal resistance of Enterobacter sakazakii in infant milk formula

Infant milk formula has been identified as a potential source of Enterobacter sakazakii. This bacterium can cause a severe form of neonatal meningitis and necrotizing entercolitis. This study determined the effect of acid, alkaline, chlorine and ethanol stresses on the thermal inactivation of E. sakazakii in infant milk formula. Stressed cells were mixed with reconstituted powdered infant milk formula (PIMF) at temperatures between 52 and 58°C for various time periods or mixed with PFMF prior to reconstitution with water at temperatures between 50 and 100°C. The D- and z-values of the cells were determined using linear regression analysis. Detergent and sanitizer stresses decreased the thermal resistance of E. sakazakii in powdered and reconstituted infant milk formula. The values for Z)- acid, alkaline, chlorine and ethanol stressed E. sakazakii at 52-58°C were 14.57-0.54, 12.07-0.37, 10.08-0.40 and 11.61-0.50 min, respectively. The values of alkaline, chlorine and ethanol stressed cells were significantly lower than those of unstressed cells. Only the z-value (4.4°C) of ethanol stressed E. sakazakii was significantly different than that of unstressed cells (4.12°C). Reconstitution at 60°C did not significantly reduce the number of pre-stressed E. sakazakii cells compared with unstressed control cells, whereas significant decreases were obtained at 70°C. Using water at 70°C during the preparation of reconstituted PIMF before feeding infants, may be a suitable and applicable means of reducing the risk of E. sakazakii in the formula. The results of this study may be of use to regulatory agencies, infant milk producers and infant caregivers to design heating processes to eliminate E. sakazakii that may be present in infant milk formula

Effect of desiccation, starvation, heat, and cold stresses on the thermal resistance of Enterobacter sakazakii in rehydrated infant milk formula

Enterobacter sakazakii has been implicated in outbreaks of meningitis, septicemia, and necrotizing enterocolitis in immunocompromised and premature neonates. In this study, the effect of desiccation stress, starvation stress, heat shock and cold shock on thermal inactivation of E. sakazakii in rehydrated infant milk formula was evaluated. Stressed cells were mixed with rehydrated infant milk formula at 52, 54, 56, and 58°C for various time periods. The D- and z-values were determined by using linear regression analysis. Z)-values for unstressed E. sakazakii at 52, 54, 56 and 58°C were 15.33, 4.53, 2.00 and 0.53 min, respectively. Desiccation and heat stress, but not starvation or cold stress, caused significant reduction in Z)-values. For example, D52 was 15.33 min for unstressed cells compared with 8.72 and 7.36 after desiccation and heat stress. Z-values of 53 desiccated, starved, heat shocked and cold shocked E. sakazakii were not significantly different from unstressed cells (4.22°C). The results of this study may be of use to regulatory agencies, infant milk producers and infant caregivers to design heating processes to eliminate E. sakazakii that may be present in infant milk formula

Survival and growth of Cronobacter species (Enterobacter) sakazakii in wheat-based infant follow on formulas

Aim: To determine the survival and growth characteristics of Cronobacter species (Enterobacter sakazakii) in infant wheat-based formulas reconstituted with water, milk, grape juice or apple juice during storage. Methods and Results: Infant wheat-based formulas were reconstituted with water, UHT milk, pasteurized grape or apple juices. The reconstituted formulas were inoculated with C. sakazakii and C. muytjensii and stored at 4, 25 or 37°C for up to 24h. At 25 and 37°C, Cronobacter grew more (>5 logio) in formulas reconstituted with water or milk than those prepared with grape or apple juices (ca. 2-3 logio). The organism persisted, but did not grow in any formulas stored at 4°C. Formulas reconstituted with water and milk decreased from pH 6.0 to 4.8-5.0 after 24h, whereas the pH of the formulas reconstituted with fruit juices remained at their initial pH values, ca. pH 4.8-5.0. Conclusion: C sakazakii and C muytjensii can grow in reconstituted wheat-based formulas. If not immediately consumed, these formulas should be stored at refrigeration temperatures to reduce the risk of infant infection. Significance and Impact of the Study: The results of this study will be of use to regulatory agencies and infant formula producers to recommend storage conditions that reduce the growth of Cronobacter in infant wheat-based formulas