A comprehensive review on carotenoids in foods and feeds: status quo, applications, patents, and research needs.

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN, www.eurocaroten.eu, https://www.cost.eu/actions/CA15136/#tabs|Name:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.

Evaluation of Web-based Dietary Assessment Software for Children: comparing reported fruit, juice and vegetable intakes with plasma carotenoid concentration and school lunch observations.

Web-based Dietary Assessment Software for Children (WebDASC) was developed to estimate dietary intake in a school meal intervention study among 8- to 11-year-old Danish children. The present study validates self-reported fruit, juice and vegetable (FJV) intakes in 8- to 11-year-old children by comparing intake with plasma carotenoid concentration, and by comparing the reported FJV intake to actually eaten FJV, as observed by a photographic method. A total of eighty-one children, assisted by parents, reported their diet for seven consecutive days. For the same five schooldays as they reported their diet, the children's school lunch was photographed and weighed before and after eating. In the week after the diet reporting, fasting blood samples were taken. Self-reported intake of FJV and estimated intake of carotenoids were compared with plasma carotenoid concentration. Accuracy of self-reported food and FJV consumption at school lunch was measured in terms of matches, intrusion, omission and faults, when compared with images and weights of lunch intake. Self-reported intake of FJV was significantly correlated with the total carotenoid concentration (0·58) (P< 0·01). Fruit and juice consumption showed higher correlations than vegetables with plasma carotenoid concentration (0·38 and 0·42 v. 0·33) (P< 0·01). A total of 82 % of the participants fell into the same or adjacent quartiles when cross-classified by FJV intake and carotenoids biomarkers. WebDASC attained 82 % reporting matches overall and a higher percentage match for reporting fruits compared with beverages. The present study indicated that WebDASC can be used to rank 8- to 11-year-old Danish children according to their intake of FJV overall and at school meals.

Evaluation of flavonoids and enterolactone in overnight urine as intake biomarkers of fruits, vegetables and beverages in the Inter99 cohort study using the method of triads.

Since collection of 24 h urine samples is very time consuming and difficult to obtain, epidemiological studies typically only obtain spot urine samples. The aim of the present study was to evaluate whether flavonoids and enterolactone in overnight urine could substitute flavonoids and enterolactone in 24 h urine as an alternative and more feasible biomarker of fruit, vegetable and beverage intake. A total of 191 individuals in the Inter99 cohort in Denmark completed the validation study. Concentrations of nine urinary flavonoid aglycones (quercetin, isorhamnetin, tamarixetin, kaempferol, hesperetin, naringenin, eriodictyol, phloretin and apigenin) and enterolactone were determined in overnight and 24 h urine samples, and their validity as biomarkers of fruit, vegetable and beverage intake was evaluated in relation to two independent reference methods (Inter99 FFQ data and plasma carotenoids) by using the method of triads. The intakes of fruit, juice, vegetables and tea reported in the FFQ were reflected by the flavonoid biomarker both in overnight and 24 h urine samples. Validity coefficients for the flavonoid biomarker in overnight urine ranged from 0·39 to 0·49, while the corresponding validity coefficients for the biomarker in 24 h urine ranged from 0·43 to 0·66. Although the validity coefficients were lower for overnight urine than for the 24 h urine flavonoid biomarker, they were still of acceptable magnitude. In conclusion, the results indicate that flavonoids and enterolactone in overnight urine samples may be used as a more feasible biomarker than 24 h urine for the assessment and validation of fruit, juice, vegetable and tea intakes in epidemiological studies.

Quantifying benefits of the Danish transfat ban for coronary heart disease mortality 1991-2007: Socioeconomic analysis using the IMPACTsec model.

Denmark has experienced a remarkable reduction in CVD mortality over recent decades. The scale of the health contribution from the Danish regulation on industrially produced trans fatty acid (ITFA) has therefore long been of interest. Thus the objective was to determine health and equity benefits of the Danish regulation on ITFA content in Danish food, by quantifying the relative contributions of changes in ITFA intake, other risk factors and treatments on coronary heart disease (CHD) mortality decline from 1991 to 2007 in Denmark, stratified by socioeconomic group. To evaluate the effects of the ITFA ban (Danish Order no. 160 of March 2003) the Danish IMPACTSEC model was extended to quantify reductions in CHD deaths attributable to changes in ITFA (%E) intake between 1991-2007. Population counts were obtained from the Danish Central Office of Civil Registration, financial income from Statistics Denmark and ITFA intake from Dan-MONICA III (1991) and DANSDA (2005-2008). Participants were adults aged 25-84 years living in Denmark in 1991 and 2007, stratified by socioeconomic quintiles. The main outcome measure was CHD deaths prevented or postponed (DPP). Mean energy intake from ITFA was decimated between 1991 and 2007, falling from 1.1%E to 0.1%E in men and from 1·0%E to 0·1%E in women. Approximately 1,191 (95% CI 989-1,409) fewer CHD deaths were attributable to the ITFA reduction, representing some 11% of the overall 11,100 mortality fall observed in the period. The greatest attributable mortality falls were seen in the most deprived quintiles. Adding ITFA data to the original IMPACTsec model improved the overall model fit from 64% to 73%. In conclusion: Denmark's mandatory elimination of ITFA accounted for approximately 11% of the substantial reduction in CHD deaths observed between 1991 and 2007. The most deprived groups benefited the most, thus reducing inequalities. Adopting the Danish ITFA regulatory approach elsewhere could substantially reduce CHD mortality while improving health equity.

A cross-sectional study on trans-fatty acids and risk markers of CHD among middle-aged men representing a broad range of BMI.

Intake of trans-fatty acids (TFA), especially industrially produced TFA (I-TFA), has been associated with the risk of CHD through influence on serum lipid levels. Other causal pathways remain less investigated. In the present cross-sectional study of middle-aged men representing a broad range of BMI, the association between intake of TFA, I-TFA and ruminant TFA (R-TFA) and obesity-associated risk markers of CHD was assessed. The study comprised 393 Danish men (median age 49 years) with a median BMI of 28·4 kg/m(2). Intake of TFA was estimated based on 7 d dietary records, whereas outcomes of interest (waist circumference, sagittal abdominal diameter, percentage of truncal fat, C-reactive protein, IL-6, blood lipids, blood pressure, HbA1c and insulin sensitivity index) were obtained through clinical examination. The associations were assessed by linear regression analysis. The median intake of total TFA among the 393 men was 1·3 g/d, covering a daily I-TFA intake of 0·4 g (10-90th percentile 0·0-1·0) and R-TFA intake of 0·9 g (10-90th percentile 0·4-1·8). Intake of these amounts of TFA showed no significant associations with abdominal fatness, inflammatory markers, blood lipids, blood pressure and insulin homeostasis. Among middle-aged men with a generally low intake of TFA, neither I-TFA nor R-TFA was significantly related to obesity-associated risk markers of CHD. The decreased average intake of I-TFA in Denmark since 1995 is suggested to effectively prevent occurrence of the adverse metabolic changes and health consequences, which have formerly been observed in relation to, especially, I-TFA intake.

Effects of organic and conventional growth systems on the content of carotenoids in carrot roots, and on intake and plasma status of carotenoids in humans.

BACKGROUND: The demand for organic food products has increased during the last decades due to their probable health effects, among others. A higher content of secondary metabolites such as carotenoids in organic food products has been claimed, though not documented, to contribute to increased health effects of organic foods. The aim was to study the impact of organic and conventional agricultural systems on the content of carotenoids in carrots and human diets. In addition, a human cross-over study was performed, measuring the plasma status of carotenoids in humans consuming diets made from crops from these agricultural systems. RESULTS: The content of carotenoids in carrot roots and human diets was not significantly affected by the agricultural production system or year, despite differences in fertilisation strategy and levels. The plasma status of carotenoids increased significantly after consumption of the organic and conventional diets, but no systematic differences between the agricultural production systems were observed. CONCLUSION: The expected higher content of presumed health-promoting carotenoids in organic food products was not documented in this study.

Intake of Unprocessed and Processed Meat and the Association with Cardiovascular Disease: An Overview of Systematic Reviews.

We conducted an overview of systematic reviews to summarize reviews of cohort studies on intake of unprocessed and processed meat and the risk of cardiovascular disease (CVD), coronary heart disease (CHD), and stroke. Systematic reviews of cohort studies published between January 2010 and August 2020 were identified through a systematic literature search in PubMed, Embase, and Web of Science. The quality of how each review was conducted was assessed and the overall confidence in the results of each review was rated using AMSTAR 2. The quality of evidence of each meta-analysis was graded using NutriGrade. Three reviews were included, with meta-analyses of unprocessed red meat and CVD (n = 1) and stroke (n = 2); unprocessed poultry and stroke (n = 1); and processed meat and CVD (n = 1), CHD (n = 1), and stroke (n = 3). The overall confidence in the results of each review was rated as critically low. The meta-evidence was graded moderate for a positive association between unprocessed red meat and stroke and moderate for a positive association between processed meat and CHD and stroke. For other associations the meta-evidence was graded as low or very low. In conclusion, the associations between unprocessed and processed meat with CVD and major subtypes of CVD have not been extensively investigated.

Intake of dairy products and associations with major atherosclerotic cardiovascular diseases: a systematic review and meta-analysis of cohort studies.

Specific types of dairy products may be differentially associated with atherosclerotic cardiovascular disease (CVD). We conducted a systematic review and meta-analysis of cohort studies to summarize findings on the associations between total dairy product intake and intake of dairy product subgroups and the risk of major atherosclerotic CVDs in the general adult population. Our protocol was registered in PROSPERO (CRD42019125455). PubMed and Embase were systematically searched through 15 August 2019. For high versus low intake and dose-response meta-analysis, random-effects modelling was used to calculate summary risk ratios (RR). There were 13 cohort studies included for coronary heart disease (CHD), 7 for ischemic stroke and none for peripheral artery disease. High-fat milk was positively associated with CHD (RR 1.08 (95% confidence interval 1.00-1.16) per 200 g higher intake/day) and cheese was inversely associated with CHD (RR 0.96 (95% confidence interval 0.93-0.98) per 20 g higher intake/day). Heterogeneity, however, was observed in high versus low meta-analyses. Milk was inversely associated with ischemic stroke in high versus low meta-analysis only. In conclusion, this systematic review indicates a positive association of high-fat milk and an inverse association of cheese with CHD risk. The findings should be interpreted in the context of the observed heterogeneity.

Impact of a sodium-reduced bread intervention with and without dietary counseling on sodium intake-a cluster randomized controlled trial among Danish families.

BACKGROUND/OBJECTIVES: Excessive intake of sodium is a dietary risk factor for morbidity and mortality. Currently, intake of sodium is much higher than the recommended level in most western countries, and effective strategies to reduce population sodium intake are lacking. The objective of the present study was to investigate the effect of two different sodium reduction strategies on the intake of sodium, potassium, and the sodium to potassium ratio among Danish families SUBJECTS/METHODS: The study was a 4-month, single-blinded, cluster randomized controlled trial with a parallel design. Eighty-nine healthy Danish families, with a minimum of one child and one parent (n = 309), were randomly assigned to receive sodium-reduced bread (Intervention A), sodium-reduced bread and dietary counseling (Intervention B) or regular sodium bread (Control). The primary outcome was change in daily sodium intake, measured by 24-h urinary sodium excretion. Secondary outcomes included changes in dietary potassium and the sodium to potassium ratio. RESULTS: No significant differences in daily sodium intake were observed in the two intervention groups compared with the control. When analyzing the results separately for children and adults, a reduction in dietary sodium of 0.6 g/day (-1.0, -0.2), p = 0.005 occurred among adults in intervention B compared with control. CONCLUSIONS: This study demonstrates that providing sodium-reduced bread in combination with dietary counseling is an effective strategy to reduce dietary sodium among adults, but the effect is lacking in children. The study was not able to show significant effects when providing sodium-reduced bread alone in neither adults nor children.

Vitamin D status assessed by a validated HPLC method: within and between variation in subjects supplemented with vitamin D3.

OBJECTIVE: The aim of this study was to develop and validate a high-pressure liquid chromatography (HPLC) method for assessing vitamin D status as 25-hydroxyvitamin D(2) (S-25OHD(2)) and 25-hydroxyvitamin D(3) (S-25OHD(3)) in serum. MATERIAL AND METHODS: We assessed the within- and between-subject variation of vitamin D status in serum samples from four different dietary intervention studies in which subjects (n = 92) were supplemented with different doses of vitamin D(3) (5-12 microg/day) and for different durations (4-20 months). RESULTS: The HPLC method was applicable for 4.0-200 nmol S-25OHD/L, while the within-day and between-days variations were 3.8 % and 5.7 %, respectively. There was a concentration-dependent difference between results obtained by a commercial radioimmunoassay and results from the HPLC method of -5 to 20 nmol 25OHD/L in the range 10-100 nmol 25OHD/L. The between-subject variation estimated in each of the four human intervention studies did not differ significantly (p = 0.55). Hence, the pooled standard deviation was 15.3 nmol 25OHD(3)/L. In the studies with 6-8 samplings during 7-20 months of supplementation, the within-subject variation was 3.9-7.2 nmol 25OHD(3)/L, while vitamin D status was in the range 47-120 nmol/L. CONCLUSIONS: The validated HPLC method was applied in samples from human intervention studies in which subjects were supplemented with vitamin D(3). The estimated standard deviation between and within subjects is useful in the forthcoming decision on setting limits for optimal vitamin D status.

Vitamin D in Wild and Farmed Atlantic Salmon (Salmo Salar)-What Do We Know?

Salmon have been widely publicized as a good dietary source of vitamin D, but recent data points to large variation in vitamin D content and differences between wild and farmed salmon. We aimed to: (1) investigate the content of vitamin D in Atlantic salmon (Salmo salar) in wild species caught in two different waters, (2) perform a 12-week feeding trial in farmed Salmo salar with 270-1440 µg vitamin D3/kg feed (4-20 times maximum level in the EU) and (3) conduct a review for the published data on the content of vitamin D in salmonids. Content of vitamin D3 in the fillet from wild salmon caught in the Baltic Sea and the North Sea was significantly different (p < 0.05), being 18.5 ± 4.6 µg/100 g and 9.4 ± 1.9 µg/100 g, respectively. In the farmed salmon the content ranged from 2.9 ± 0.7 µg vitamin D3/100 g to 9.5 ± 0.7 µg vitamin D3/100 g. Data from 2018 shows that farmed salmon contained 2.3-7.3 µg vitamin D3/100 g. Information on the content of vitamin D in wild and farmed salmonids is very limited, which calls for further research to ensure a sustainable production of salmon with adequate vitamin D.

The use of a plant enzyme for rapid and sensitive analysis of naturally-occurring folates in food by liquid chromatography-tandem mass spectrometry.

A rapid, sensitive and reproducible method for analysis of naturally-occurring folates and folic acid in food has been developed and validated. A single-enzyme extraction step, in which a pure recombinant enzyme of plant origin (Arabidopsis thaliana) was used, enabled fast and reproducible deglutamylation during folate extraction within the incubation time of 1 h. Six commonly occurring folate forms (tetrahydrofolate, 5,10-methenyltetrahydrofolate, 10-formylfolic acid, 5-formyltetrahydrofolate, folic acid and 5-methyltetrahydrofolate) were detected and quantified in 9 min using liquid chromatography-tandem mass spectrometry (LC-MS/MS). 13C5-labeled 5-formyltetrahydrofolate, 13C5-labeled folic acid and 13C5-labeled 5-methyltetrahydrofolate were used as internal standards for the quantification. The method is described by a calibration curve (R2>0.99 and trueness 85-115%), a limit of quantification at 0.1 µg/100 g, trueness at 80-120% in spiked samples and certified reference materials, and a precision <10%. However, the precision in quantification of tetrahydrofolate was not within the acceptable limits due to the lack of use of the corresponding internal standard. An interconversion study of unstable formyl forms was performed which showed that 50% of 5,10-methenyltetrahydrofolate is converted to 5-formyltetrahydrofolate during the analysis. The developed LC-MS/MS method is a candidate for a future standard method for folate analysis in food.

The Nutritional Quality of Lunch Meals Eaten at Danish Worksites.

Monitoring the nutritional environment is important to help inform future initiatives to improve access to healthy foods. The objective was to examine the nutritional quality of lunch meals eaten at 15 worksite canteens and then to compare with results from a study conducted 10 years before. The duplicate-portion-technique with subsequent chemical analysis was used to quantify 240 customers' lunch intake. Estimated mean energy intake was 2.1 MJ/meal (95% confidence interval (CI): 1.9 to 2.4 g/meal) and estimated energy density 599 kJ/100 g (95% CI 550 to 653 kJ/100 g). Energy density of the male participants' meals were significantly higher compared with the female participants' meals (+55 kJ/100 g, 95% CI: +12 to +98 kJ/100 g, p = 0.012), whereas no gender differences were found in macronutrient distribution or fruit and vegetable intake. Compared to the study conducted 10 years before several significant changes were observed, including an increase in mean estimated intake of fruit and vegetables (+38 g/meal, 95% CI: 19 to 57 g/meal, p < 0.001) and a decrease in energy density (-76 kJ/100 g, 95% CI: -115, -37 kJ/100 g, p < 0.001). In conclusion, this study suggests an equalization of gender differences in fruit and vegetable intake and a possible improvement in the nutritional quality of canteen lunch meals over a 10-year period.

The Salt Content of Lunch Meals Eaten at Danish Worksites.

Monitoring levels of sodium (salt) in meals consumed out-of-home is needed to support effective implementation of salt-reduction strategies. The objective of the study was to examine lunch salt intake at 15 worksite canteens and to compare with results from a comparable study conducted 10 years before. A duplicate-portion-technique with subsequent chemical analysis was used to quantify 240 customers' lunch salt intake. Estimated mean salt intake was 2.6 g/meal (95% Cl: 2.2 to 3.0 g/meal) and 0.78 g/100 g (95% Cl: 0.69 to 0.88 g/100 g). Salt intake measured both as g per meal and per 100 g was found to be significantly higher for male compared with female participants (+0.10 g/100 g, 95% Cl: +0.02 to +0.17 g/100 g, p = 0.011). Compared with the study conducted 10 years before, there was a significantly lower estimated salt intake of 0.5 g/meal (95% CI: -0.8 to -0.2 g/meal, p = 0.001), suggesting a possible reduction in canteen lunch salt intake during a 10-year period. Still, 40% of the meals exceeded the Nordic Keyhole label requirements of maximum 0.8 g salt per 100 g for ready meals. A further reduction of salt intake is warranted to comply with salt reduction targets.

Effects of red grape skin and seed extract supplementation on atherosclerosis in Watanabe heritable hyperlipidemic rabbits.

Epidemiological studies have suggested an association between consumption of red wine and other polyphenolic compounds and prevention of cardiovascular diseases. In the present study, Watanabe heritable hyperlipidemic (WHHL) rabbits were used to investigate the effects of polyphenols in a red grape skin and seed extract (GSE) on the development of atherosclerosis. WHHL rabbits received either semisynthetic diet (casein based) or semisynthetic diet added GSE over a period of 15 wk. Plasma lipids and aortic cholesterol accumulation were measured. Feeding semisynthetic diet was associated with increasing hypercholesterolemia, which was developing slower in GSE group compared to the controls as recorded by significantly lower plasma cholesterol in dosage week 7 (males: P < 0.05, females: P < 0.01) and 11 (males: P < 0.01). Aortic atherosclerosis evaluated as the cholesterol content in aortic tissue was comparable in the control and GSE-dosed females, but it was significantly reduced in the abdominal part of GSE-dosed male compared to the controls (P < 0.05). In conclusion, feeding GSE extract to WHHL rabbits had no significant effects in females but was associated with transient less hypercholesterolemic response to semisynthetic diet and, furthermore, retarded the development of aortic atherosclerosis in males as demonstrated by significantly lower cholesterol content in the abdominal part.

Contrasting effect of fish oil supplementation on the development of atherosclerosis in murine models.

OBJECTIVE: Increased fish oil intake is associated with protection against coronary heart disease and sudden death, while effects on atherosclerosis are controversial. We explored the effects of supplementing fish oil (rich in n-3 polyunsaturated fatty acids, PUFA) or corn oil (rich in n-6 PUFA) in two different models of atherosclerosis. METHODS AND RESULTS: Sixty-three low density lipoprotein receptor-deficient (LDLR(-/-)) mice and sixty-nine apolipoprotein E-deficient (apoE(-/-)) mice were fed diets without supplementations or supplemented with either 1% fish oil or 1% corn oil. In apoE(-/-) mice, neither fish oil nor corn oil had any major impact on plasma lipids or atherosclerosis. In LDLR(-/-) mice, conversely, the fish oil and the corn oil group had lower levels of LDL-cholesterol and triglycerides and had lesser atherosclerosis in the aortic root and in the entire aorta (p < 0.01 versus unsupplemented group). Atherosclerosis was significantly less in the fish oil group compared with the corn oil group when evaluated en face in the aortic arch (area positive to lipid staining: 32% with fish oil versus 38% with corn oil; 48% with unsupplemented diet). CONCLUSIONS: n-3 and n-6 PUFA supplementation retarded the development of atherosclerosis in LDLR(-/-) mice, with a stronger effect seen with n-3 PUFA. There was an important strain-dependence of the effect, with no protection against atherosclerosis in apoE(-/-) mice.

A trans world journey.

A high intake of industrially produced trans fatty acids (IP-TFA) is associated with increased risk of coronary heart disease (CHD), and a daily intake as low as possible is required to minimize health risks. To achieve this at the individual level in Denmark, legislation limited IP-TFA in foods to a maximum of 2% of fat content from 2004. We assessed the potential exposure of consumers to IP-TFA by analysing popular foods in Denmark, and in 25 other countries. Fifty-five servings of French fries and chicken nuggets, 87 packages of microwave popcorn, and 393 samples of biscuits/cakes/wafers with "partially hydrogenated vegetable fat" listed high on the food label were bought between November 2004 and February 2006. The content of IP-TFA was analysed by standardized methodology. We defined a "high trans menu" as a large size serving of French fries and nuggets, 100 g of microwave popcorn, and 100 g of biscuits/wafers/cakes. The amounts of IP-TFA in a "high trans menu" was 30 g in 2001 in Denmark, but was reduced to less than 1g in 2005. By contrast, a "high trans menu" provided more than 20 g in 17 out of 18 countries, with Hungary, Czech Republic, Poland, Bulgaria, and USA, ranking highest with 42, 40, 38, 37, and 36 g, respectively. The legislation in Denmark has reduced the exposure of IP-TFA at the individual level without noticeable effect on availability, price, and quality of foods previously containing high amounts of IP-TFA. The findings of high concentrations of IP-TFA in popular foods outside Denmark suggest that millions of people inside and outside EU have intakes of IP-TFA that may increase their risk of CHD. The Danish experience demonstrates that this risk can be eliminated.

The effect of the regulation on trans fatty acid content in Danish food.

The content of trans fatty acids (TFA) in Danish food has been monitored for the last 30 years. In margarines and shortenings the content of TFA has steadily declined from about 10 g/100 g margarine in the seventies to practically no TFA in margarines in 1999. In order to efficiently reduce the health risk related to TFA, Denmark decided to impose a maximum level of 2 g/100 g fat on industrially produced TFA (IP-TFA) with the Danish Order no. 160 of March 2003, as labelling was deemed insufficient to protect the consumers, especially risk groups like children or people with high intake of fast foods. A broader range of food was monitored with 253 samples in 2003 and 148 samples in 2005 after the Danish regulation was in effect. The investigations show that the TFA content has been reduced or removed from the products with high TFA content originally, like French fries, microwave oven popcorn and various bakery products, so IP-TFA are now without any significance for the intake of TFA in Denmark.

Intake of ruminant trans fatty acids and risk of coronary heart disease-an overview.

Epidemiological studies have shown a strong direct (positive) association between the intake of trans fatty acids (TFA) and the risk of coronary heart disease (CHD), primarily accounted for by industrially produced TFA (IP-TFA). However, comparisons between ruminant TFA (R-TFA) and IP-TFA and risk of CHD have been based on quintiles of intake, which implies that the associations between the two sources of TFA and the risk of CHD were described across different ranges of intake. Controlled metabolic studies of the effect of intake of total and specific R-TFA on CHD risk factors are warranted. Moreover, further epidemiological studies of intake of R-TFA and risk of CHD in populations with a high intake of R-TFA are warranted.

A comparative study of two food model systems to test the survival of Campylobacter jejuni at -18 degrees C.

The survival of Campylobacter jejuni NCTC 11168 was tested at freezing conditions (-18 degrees C) over a period of 32 days in two food models that simulated either (i) the chicken skin surface (skin model) or (ii) the chicken juice in and around a broiler carcass (liquid model). In the skin model, cells were suspended in chicken juice or brain heart infusion broth (BHIB) and added to 4-cm2 skin pieces, which were subsequently stored at -18 degrees C. In the liquid model, cells were suspended in chicken juice or BHIB and stored at -18 degrees C. The decrease in the number of viable C. jejuni NCTC 11168 cells was slower when suspended in chicken juice than in BHIB. After freezing for 32 days, the reductions in the cell counts were 1.5 log CFU/ml in chicken juice and 3.5 log CFU/ml in BHIB. After the same time of freezing but when inoculated onto chicken skin, C. jejuni NCTC 11168 was reduced by 2.2 log units when inoculated in chicken juice and 3.2 log units when inoculated into BHIB. For both models, the major decrease occurred within the first 24 h of freezing. The results obtained in the liquid model with chicken juice were comparable to the reductions of Campylobacter observed for commercially processed chickens. The survival at -18 degrees C in the liquid model was also tested for three poultry isolates and three human clinical isolates of the serotypes 1.44, 2, and 4 complex. As observed for C. jejuni NCTC 11168, all the strains survived significantly better in chicken juice than in BHIB and were not notably influenced by serotype or origin. The findings indicate that the composition of the medium around the bacteria, rather than the chicken skin surface, is the major determining factor for the survival of C. jejuni at freezing conditions. The liquid model with chicken juice was therefore the best model system to study the freezing tolerance in Campylobacter strains.