Effect of storage temperatures and stresses on the survival of Salmonella spp. in halva.

The presence of Salmonella spp. in halva has been associated with foodborne illnesses and product recalls from the markets. This study investigated the effect of environmental stresses on the survival of Salmonella spp. in halva during storage for 12 months at 10 and 25°C (log (N0 /N) g-1 ). Halva samples were inoculated with a cocktail of four strains of unstressed, desiccation stressed or heat stressed Salmonella (106 -107  CFU per gram). In general, survival of Salmonella spp. in halva decreased significantly (P Ë‚ 0·05) as storage time and temperature increased. At the end of halva shelf life at 10°C, the initial populations of unstressed, desiccation stressed or heat stressed Salmonella spp. decreased by 2·7, 2·6 or 2·8 log CFU per gram (reduction rate c. 0·2 log CFU per month), respectively. While at 25°C, the populations decreased 5·2, 6·7 or 6·3 log CFU per gram, respectively (reduction rate c. 0·4-0·5 log CFU per month). The populations of stressed Salmonella spp. in halva samples were not significantly different (P ≥ 0·05) from populations of unstressed cells during storage at 10 and 25°C, except during the last 3 months of storage at 25°C when populations of unstressed cells were higher (P < 0·05). Exposing Salmonella spp. to desiccation or heat stress prior product contamination may play a role in Salmonella spp. survival in halva during storage. SIGNIFICANCE AND IMPACT OF THE STUDY: Contamination of halva (tahini halva) with Salmonella from raw materials or during production was documented. Halva and tahini have been involved in salmonellosis outbreaks in different countries. The study demonstrated enhanced survivability of stressed and unstressed Salmonella spp. in halva over a 12-month storage period at 10 and 25°C with lower log reductions than expected. Exposing Salmonella spp. to desiccation or heat stress prior product contamination may play a role in microbial survival in halva during storage. These findings serve as a model to halva producers to implement control measures to prevent Salmonella spp. contamination in halva.

Heat resistance of Cronobacter species (Enterobacter sakazakii) in milk and special feeding formula.

AIM: To determine D- and z-values of Cronobacter species (Enterobacter sakazakii) in different reconstituted milk and special feeding formula and the effect of reconstitution of powdered milk and special feeding formula with hot water on the survival of the micro-organism. METHODS AND RESULTS: Five Cronobacter species (four C. sakazakii isolates and C. muytjensii) were heated in reconstituted milk or feeding formula pre-equilibrated at 52-58 degrees C for various times or mixed with powdered milk or feeding formula prior to reconstitution with water at 60-100 degrees C. The D-values of Cronobacter at 52-58 degrees C were significantly higher in whole milk (22.10-0.68 min) than in low fat (15.87-0.62 min) or skim milk (15.30-0.51 min) and significantly higher in lactose-free formula (19.57-0.66 min) than in soy protein formula (17.22-0.63 min). The z-values of Cronobacter in reconstituted milk or feeding formula ranged from 4.01 degrees C to 4.39 degrees C. Water heated to > or =70 degrees C and added to powdered milk and formula resulted in a > 4 log(10) reduction of Cronobacter. CONCLUSIONS: The heat resistance of Cronobacter should not allow the survival of the pathogen during normal pasteurization treatment. The use of hot water (> or =70 degrees C) during reconstitution appears to be an effective means to reduce the risk of Cronobacter in these products. SIGNIFICANCE AND IMPACT OF THE STUDY: This study supports existing data available to regulatory agencies and milk producers that recommended heat treatments are sufficient to substantially reduce risk from Cronobacter which may be present in these products.

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

AIMS: 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, ultra high temperature milk, pasteurized grape or apple juices. The reconstituted formulas were inoculated with Cronobacter sakazakii and Cronobacter muytjensii and stored at 4, 25 or 37 degrees C for up to 24 h. At 25 and 37 degrees C, Cronobacter grew more (>5 log(10)) in formulas reconstituted with water or milk than those prepared with grape or apple juices (c. 2-3 log(10)). The organism persisted, but did not grow in any formulas stored at 4 degrees C. Formulas reconstituted with water and milk decreased from pH 6.0 to 4.8-5.0 after 24 h, whereas the pH of the formulas reconstituted with fruit juices remained at their initial pH values, c. pH 4.8-5.0. CONCLUSIONS: Cronobacter 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.

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

This study determined the effect of acid, alkaline, chlorine, and ethanol stresses on the thermal inactivation of Enterobacter sakazakii in infant milk formula. Unstressed or stressed cells were mixed with reconstituted powdered infant milk formula (PIMF) at temperatures between 52 and 58 degrees C for various time periods or mixed with PIMF prior to reconstitution with hot water between 50 and 100 degrees C. D- and z-values were determined using liner regression analysis. In general, detergent and sanitizer stresses decreased the thermal resistance of E. sakazakii in infant milk formula. The results of this study may be of use to regulatory agencies, manufacturers, and infant caregivers to design heating processes to eliminate E. sakazakii.

Enhancing the antimicrobial effects of bovine lactoferrin against Escherichia coli O157:H7 by cation chelation, NaCl and temperature.

AIM: To evaluate the effect of NaCl, growth medium and temperature on the antimicrobial activity of bovine lactoferrin (LF) against Escherichia coli O157:H7 in the presence of different chelating agents. METHODS AND RESULTS: LF (32 mg ml(-1)) was tested against E. coli O157:H7 strain 3081 in Luria broth (LB) and All Purpose Tween (APT) broth with metal ion chelators sodium bicarbonate (SB), sodium lactate (SL), sodium hexametaphosphate (SHMP), ethylene diamine tetraacetic acid (EDTA) or quercetin at 0.5 and 2.5% NaCl at 10 and 37 degrees C. LF and the chelators were tested against four other E. coli O157:H7 strains in LB at 2.5% NaCl and 10 degrees C. LF alone was bacteriostatic against strains 3081 and LCDC 7283 but other strains grew. Antimicrobial effectiveness of LF was reduced in APT broth but enhanced by SB at 2.5% NaCl and 10 degrees C where 4.0 log(10) CFU ml(-1) inoculated cells were killed. EDTA enhanced antimicrobial action of the LF-SB combination. SL alone was effective against E. coli O157:H7 but a reduction in its activity at 2.5% NaCl and 10 degrees C was reversed by LF. The combinations LF-SHMP and LF-quercetin were more effective at 37 degrees C and NaCl effects varied. CONCLUSIONS: LF plus SB or SL were bactericidal toward the same 3/5 E. coli O157:H7 strains and inhibited growth of the others at 2.5% NaCl and 10 degrees C. SIGNIFICANCE AND IMPACT OF THE STUDY: The combination of LF with either SL or SB shows potential for reducing viability of E. coli O157:H7 in food systems containing NaCl at reduced, but growth permissive temperature.

Changes in plasma lipids and lipoproteins associated with starting or stopping postmenopausal hormone replacement therapy. Atherosclerosis Risk in Communities Study.

The Atherosclerosis Risk in Communities Study investigators examined nearly 4000 postmenopausal women from 1987 through 1989 and 3 years later to determine changes in plasma lipids occurring with the starting or stopping of hormone replacement therapy. Women who started estrogen plus progestin therapy (n = 74) had decreases of 9.8 mg/dl in low-density lipoprotein (LDL) cholesterol and 5.8 mg/dl in apolipoprotein B and increases of 1.2 mg/dl in high-density lipoprotein (HDL) cholesterol (HDL change not significant), 13.5 mg/dl in apolipoprotein A-I, and 14.0 mg/dl in triglycerides. Women who started estrogen alone (n = 149) had similar changes, except for a much larger increase in HDL cholesterol (5.8 mg/dl), principally in HDL-2. Women who stopped hormone therapy (n = 138) had lipid changes opposite to those who started therapy, but smaller in magnitude. These results confirm those of the Postmenopausal Estrogen/Progestin Interventions Trial in a community-based longitudinal cohort: women initiating estrogen plus progestin therapy have decreases in LDL cholesterol, but the increase in HDL cholesterol is less than that for starting estrogen alone. In addition, the current study extends findings to apolipoproteins and HDL subfractions.

No association of menopause and hormone replacement therapy with carotid artery intima-media thickness. Atherosclerosis Risk in Communities (ARIC) Study Investigators.

BACKGROUND: Cardiovascular disease is the major cause of death in older women. Information on the relation of menopause and hormone replacement therapy with carotid atherosclerosis is limited. METHODS AND RESULTS: We examined cross-sectionally the association of menopausal status, years since last menstruation, and hormone replacement therapy status with carotid artery intima-media thickness as determined by B-mode ultrasound. Female participants (n = 5436) in the Atherosclerosis Risk in Communities Study without a history of symptomatic cardiovascular disease were included in the analyses. Menopause status in 45- to 54-year-old women who had never used hormone replacement therapy was not strongly associated with carotid intima-media thickness (mean = 0.65 mm and 0.67 mm in premenopausal and postmenopausal women, respectively, adjusted for age, race, cigarette years of smoking, body mass index, sport index, systolic blood pressure, use of blood pressure medications, drinking status, diabetes, and education level). In postmenopausal women aged 55 to 64 years, women with < or = 5 years since last menstruation had an adjusted average intima-media thickness (0.74 mm) comparable to those with > 5 years since last menstruation (0.75 mm) (P > .05). Although hormone replacement therapy use was associated with a more favorable lipid and hemostasis profile than nonuse, its use was not associated with intima-media thickness in postmenopausal women aged 55 to 64 years (adjusted average = 0.74 mm for current users of estrogen alone and approximately 0.75 mm each for current users of estrogen plus progestin, former users, and never users). CONCLUSIONS: The data suggest that the well-known associations of hormone replacement therapy with reductions in atherosclerotic cardiovascular disease may be attributable more to acute physiological effects, such as hemodynamic changes or reduced thrombosis, than to atherosclerosis itself.

A pharmacoeconomic model of divalproex vs. lithium in the acute and prophylactic treatment of bipolar I disorder.

BACKGROUND: Divalproex and lithium are the two most rigorously studied pharmacologic treatments for acute mania in bipolar I disorder in randomized, controlled trials. The differences between the drugs in their time course of onset, predictors of response, and side effects have potentially important pharmacoeconomic implications. METHOD: Utilizing data from published studies, the University of Cincinnati Mania Project, and a consensus panel of psychiatrists, we developed a decision-analytic model to estimate the costs of treating patients with bipolar I disorder, acutely and prophylactically, for 1 year with divalproex or lithium. RESULTS: In the overall group of patients with bipolar I disorder, initial treatment with divalproex led to costs that were 9% lower than costs for initial treatment with lithium. Cost savings associated with divalproex were greatest for patients with mixed mania and rapid cycling, whereas cost savings for patients with classic mania were greater for lithium. CONCLUSION: According to the decision-analytic model developed in this study, divalproex, possibly because of a more rapid rate of antimanic activity associated with oral loading, is a less costly treatment than lithium in the acute and prophylactic treatment of patients with bipolar I disorder over 1 year.

Can postmenopausal hormone replacement improve plasma lipids in women with diabetes? The Atherosclerosis Risk in Communities Study Investigators.

OBJECTIVE: to evaluate the association of postmenopausal hormone replacement with plasma lipids in diabetic women. RESEARCH DESIGN AND METHODS: Cross-sectional data from a multiracial population study were used to evaluate the relationship of hormone replacement status with plasma lipids in diabetic (n = 694) versus nondiabetic (n = 5,321) postmenopausal women. RESULTS: Although diabetic women who currently used hormone replacement had higher adjusted mean HDL cholesterol levels than those who did not (56.9 vs. 53.6 mg/dl), they had proportionately lower hormone-related increases in HDL, HDL2, and HDL3 cholesterol than did nondiabetic women (HDL cholesterol 64.9 [current users] vs. 55.7 mg/dl [those who never used hormones]). There was a trend toward greater triglyceride values with hormone replacement in diabetic women (156.6 [current users] vs. 125.4 mg/dl [those who never used hormones]) than in nondiabetic women (143.3 [current users] vs. 123.7 mg/dl [those who never used hormones]). LDL cholesterol and apolipoprotein B levels were lower and apolipoprotein A-I levels were higher with hormone replacement, to a similar degree in diabetic and nondiabetic women. CONCLUSIONS: Diabetic women appear to have a blunted response to the HDL-raising effects of estrogen and an exaggerated hypertriglyceridemic response. This may result in attenuated cardioprotection from postmenopausal hormone replacement therapy and potentially an increased risk of acute pancreatitis from hypertriglyceridemia. The risks and benefits of postmenopausal hormone replacement need to be carefully weighed in diabetic women.

Associations of serum and dietary magnesium with cardiovascular disease, hypertension, diabetes, insulin, and carotid arterial wall thickness: the ARIC study. Atherosclerosis Risk in Communities Study.

The objective of this study was to examine the relationships of serum and dietary magnesium (Mg) with prevalent cardiovascular disease (CVD), hypertension, diabetes mellitus, fasting insulin, and average carotid intimal-medial wall thickness measured by B-mode ultrasound. A cross-sectional design was used. The setting was the Atherosclerosis Risk in Communities (ARIC) Study in four US communities. A total of 15,248 participants took part, male and female, black and white, aged 45-64 years. Fasting serum Mg, lipids, fasting glucose and insulin were measured; as was usual dietary intake by food frequency questionnaire and carotid intima-media thickness by standardized B-mode ultrasound methods. The results showed that serum Mg levels and dietary Mg intake were both lower in blacks than whites. Mean serum Mg levels were significantly lower in participants with prevalent CVD, hypertension, and diabetes than in those free of these diseases. In participants without CVD, serum Mg levels were also inversely associated with fasting serum insulin, glucose, systolic blood pressure and smoking. Dietary Mg intake was inversely associated with fasting serum insulin, plasma high density lipoprotein-cholesterol, systolic and diastolic blood pressure. Adjusted for age, race, body mass index, smoking, hypertension, Low density lipoprotein-cholesterol, and field center, mean carotid wall thickness increased in women by 0.0118 mm (p = 0.006) in diuretic users and 0.0048 mm (p = 0.017) in nonusers for each 0.1 mmol/l decrease in serum Mg level; the multivariate association in men was not significant. In conclusion, low serum and dietary Mg may be related to the etiologies of CVD, hypertension, diabetes, and atherosclerosis.

Fasting hyperinsulinemia and cardiovascular disease risk factors in nondiabetic adults: stronger associations in lean versus obese subjects. Atherosclerosis Risk in Communities Study Investigators.

The association between hyperinsulinemia and atherogenic risk factors has not been well studied in blacks and may be different for obese versus lean individuals. To investigate this possibility and to confirm the associations of hyperinsulinemia with cardiovascular disease risk factors in blacks and whites, we analyzed the joint associations of fasting serum insulin and obesity with risk factors in the Atherosclerosis Risk in Communities (ARIC) Study (1,293 black men, 4,797 white men, 2,033 black women, and 5,445 white women). Insulin values > or = 90th percentile (> or = 21 microU/mL) constituted hyperinsulinemia; body mass index (BMI) values > or = 27.3 kg/m2 for women and > or = 27.8 for men constituted obesity. Participants with hyperinsulinemia in all four race-sex groups had more atherogenic levels of most risk factors studied than those with normoinsulinemia. Among black men and women, mean levels of triglycerides, low-density lipoprotein cholesterol (LDL-C), apolipoprotein (apo) B, glucose, and fibrinogen (men only) were higher in hyperinsulinemic lean participants as compared with the normoinsulinemic obese group. Furthermore, most associations between insulin level and risk factors were stronger among lean versus obese subjects. For example, among lean black men, the difference in mean triglyceride concentration between those with hyperinsulinemia and those with normoinsulinemia was 147 - 99 = 48 mg/dL; among obese black men, the difference was 155 - 121 = 34 mg/dL (P < .05 for the interaction). Generally, similar negative interactions between BMI and insulin concentration were also observed among whites.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of hormone-replacement therapy with various cardiovascular risk factors in postmenopausal women. The Atherosclerosis Risk in Communities Study Investigators.

BACKGROUND: Most epidemiologic studies of cardiovascular disease in postmenopausal women suggest that estrogen-replacement therapy has a protective effect. The effects of the use of estrogen combined with progestin are less well studied. METHODS: To examine the associations of hormone-replacement therapy with concentrations of plasma lipids and hemostatic factors, fasting serum concentrations of glucose and insulin, and blood pressure, we studied 4958 postmenopausal women participating in a population-based investigation. Using cross-sectional data, we classified the women into four groups according to their use of hormone-replacement therapy: current users of estrogen alone, current users of estrogen with progestin, nonusers who had formerly used these hormones, nonusers who had never used them. RESULTS: Current users had higher mean levels of high-density lipoprotein cholesterol, its subfractions high-density lipoprotein2 and high-density lipoprotein3, and apolipoprotein A-I than nonusers and lower mean levels of low-density lipoprotein cholesterol, apolipoprotein B, lipoprotein(a), fibrinogen, antithrombin III, and fasting serum glucose and insulin. However, current users of estrogen alone had higher triglyceride, factor VII, and protein C levels than either nonusers or current users of estrogen with progestin. After making certain assumptions, we estimated that the findings, if causal, would translate into a reduction of 42 percent in the risk of coronary heart disease in users of hormones as compared with nonusers. Women using estrogen with progestin would have an even greater estimated benefit. CONCLUSIONS: A randomized trial is needed to eliminate possible selection biases in our observational study that are related to the prescription of replacement hormones. Nevertheless, hormone-replacement therapy appears to be associated with a favorable physiologic profile, which probably mediates its protective effects on cardiovascular disease. The use of estrogen combined with progestin appears to be associated with a better profile than the use of estrogen alone.