Salmonella in eggs

The report Salmonella in Eggs by the Advisory Committee on the Microbiological Safety of Foods (ACMSF) considered the scientific and epidemiological evidence up to 1992. Salmonella enteritidis phage type 4 is the most prevalent type of salmonella causing food poisoning in the UK. Microbiological and epidemiological evidence in the UK and abroad has shown a strong association between food poisoning caused by Salmonella enteritidis and the consumption of eggs and poultry. The ACMSF made recommendations on methods available to the poultry industry, the catering industry and the consumer on how to prevent food poisoning resulting from the consumption of eggs. These include eating eggs within three weeks, and storing them, whether in the home or by caterers, in a refrigerator at 8°C. Eggs must be stored at, and transported within, a system not exceeding 20°C which avoids excessive temperature fluctuations. The use of pasteurised liquid egg should be promoted as a replacement for raw eggs in dishes which traditionally have included raw egg, particularly in those not subject to further cooking prior to consumption. The Committee recommended improving hygiene in the poultry industry and that the industry (including those distributing and retailing egg products) should draw up a code of practice for the handling and storage of eggs. Once more the need for education and training was stressed.     

Four linked outbreaks of Salmonella enteritidis phage type 4 infection--the continuing egg threat

Four outbreaks of Salmonella enteritidis phage type (PT) 4 occurred among guests at functions for which a single commercial caterer supplied food. Retrospective cohort studies were used to describe the epidemiology of three of these outbreaks and identify the vehicle(s) responsible. Of 172 guests at these three events, 47 fitted the clinical case definition for illness and 24 cases were confirmed to have S. enteritidis PT4 infection. Food containing raw egg was identified epidemiologically as the likely vehicle of infection in two of the three outbreaks (odds ratios (OR) and 95% confidence intervals 9.1 (2.2-39.9) and 6.9 (1.2-46.4)). Logistic regression analysis yielded OR = 10.7 (p = 0.0022) and OR = 9.3 (p = 0.015) for egg consumption in two of the outbreaks. These outbreaks highlighted the continuing need to remind the public and commercial caterers of the potential high risks of contracting salmonella from shell eggs. Education of caterers includes advice to obtain eggs and other products from reputable and identifiable suppliers.     

Egg contribution towards the diet of pregnant Latinas

Proper nutrition during gestation is important to prevent adverse pregnancy outcomes. Eggs contain many important nutrients necessary for fetal development and human survival. Three focus groups were conducted with Latina women living in Connecticut to identify cultural beliefs toward egg consumption during pregnancy, traditional egg dishes, and methods of preparation. A cross-sectional study was then carried out with a sample of predominately Puerto Rican pregnant Latinas (N = 241) to identify the frequency of consumption of eggs and egg-containing dishes as well as methods of preparation using a tailored food frequency questionnaire modified for this population. Paired sample t-tests were used to examine if there were differences in weekly mean egg intake patterns between the year prior to the pregnancy and during pregnancy based on a Food Frequency Questionnaire. Women were categorized into eggs consumers and non-consumers if they consumed or did not consume eggs during the previous day based on 24-hour recall data. Independent-sample t-test and chi-square cross-tabulation analyses were conducted to examine the association between egg consumption and nutrient intake categories. Results showed that eggs and egg-containing traditional dishes are consumed by Latinas before and during pregnancy. Egg consumers had higher intakes of protein, fat, vitamin K, vitamin E, selenium, beta carotene, lutein and zeaxanthin, cholesterol, total polyunsaturated fatty acids, and docosahexaenoic acid. Eggs contribute significantly to the diet of pregnant Latinas.     

Egg Contribution Towards the Diet of Pregnant Latinas

Proper nutrition during gestation is important to prevent adverse pregnancy outcomes. Eggs contain many important nutrients necessary for fetal development and human survival. Three focus groups were conducted with Latina women living in Connecticut to identify cultural beliefs toward egg consumption during pregnancy, traditional egg dishes, and methods of preparation. A cross-sectional study was then carried out with a sample of predominately Puerto Rican pregnant Latinas (N = 241) to identify the frequency of consumption of eggs and egg-containing dishes as well as methods of preparation using a tailored food frequency questionnaire modified for this population. Paired sample t-tests were used to examine if there were differences in weekly mean egg intake patterns between the year prior to the pregnancy and during pregnancy based on a Food Frequency Questionnaire. Women were categorized into eggs consumers and non-consumers if they consumed or did not consume eggs during the previous day based on 24-hour recall data. Independent-sample t-test and chi-square cross-tabulation analyses were conducted to examine the association between egg consumption and nutrient intake categories. Results showed that eggs and egg-containing traditional dishes are consumed by Latinas before and during pregnancy. Egg consumers had higher intakes of protein, fat, vitamin K, vitamin E, selenium, beta carotene, lutein and zeaxanthin, cholesterol, total polyunsaturated fatty acids, and docosahexaenoic acid. Eggs contribute significantly to the diet of pregnant Latinas.     

Large outbreaks of Salmonella Typhimurium phage type 135 infections associated with the consumption of products containing raw egg in Tasmania

This report describes one of the largest egg-associated outbreaks of foodborne illness in Australia for many years. Between June and December 2005, five outbreaks of Salmonella Typhimurium phage type 135 were identified in Tasmania, leading to 125 laboratory-confirmed cases. Public health investigations included case and food handler interviews, cohort studies, environmental health investigations of food businesses, microbiological testing, traceback, and inspections and drag swabbing of an egg farm. These investigations enabled identification of foods containing raw egg or foods contaminated through inadequate food handling and/or storage procedures as possible vehicles for infection. A particular poultry farm was reported as the common source of eggs. Interventions targeting the general public and food handlers to promote better handling of egg products, and advice to egg producers regarding harm minimisation strategies led to the series of outbreaks being brought under control.     

An outbreak of Salmonella typhimurium PTI35 gastroenteritis associated with a minimally cooked dessert containing raw eggs.

In April 2000, we investigated an outbreak of gastroenteritis amongst attendees of a local community dinner in a Perth suburb. Of the 98 people interviewed (response rate 98%), 53 reported gastrointestinal symptoms (attack rate 54%). Faecal cultures from 11 cases, 2 food preparers, 1 waitress and leftover mock ice-cream dessert grew Salmonella Typhimurium PT135. Of the 3 food handlers, one was asymptomatic, another gave an unclear history of onset of illness and the waitress claimed illness onset 9 days after the dinner. A cohort study implicated fruit salad (RR 1.64 [95% CI: 1.05-2.58], p=0.017) and/or mock ice-cream dessert (RR 1.78 [95% CI: 0.91-3.52], p=0.045). Eggs used to make the mock ice-cream dessert were supplied directly from the producer who used inappropriate shell cleaning methods. The method of preparation of the dessert encouraged contamination. Salmonella species were not isolated in poultry faecal samples collected from the implicated egg farm. The cause of this outbreak was almost certainly the ice-cream dessert with contamination most likely resulting either from the eggs used to make the dessert or one or both of the food preparers, coupled with inadequate cooking of the dessert. Eggs used in preparing food for mass consumption should be sourced from distributors with approved cleaning procedures. Furthermore, pasteurised egg products or egg pulp should be used in the preparation of uncooked or minimally cooked dishes.     

Protein-bound Nε-carboxymethyllysine and Nε-carboxyethyllysine in raw and heat treated whites and yolks of hen eggs

Little is known about N^ε-carboxymethyllysine (CML) and N^ε-carboxyethyllysine (CEL), two typical advanced glycation end-products, in raw and cooked egg whites and yolks. This study was aimed to evaluate the levels of protein-bound CML and CEL in hen eggs as affected by heating (80 ℃ 6 min, 100 ℃ 30 min) and the source of eggs based upon a validated HPLC–MS/MS approach. A large biological variation in AGEs among individual raw eggs was found (e.g., CEL in yolks 1.26 – 10.57 mg/kg, n = 16). The yolk had higher levels of CML (125% more in average) and CEL (82% more in average) than the white for each raw egg, attributing to the higher protein levels and higher susceptibility of egg yolks to lipid oxidation. Heating led to significant increases (p < 0.05) of CML in egg whites and yolks, but resulted in an average of 17 – 18% decrease of CEL in egg yolks. Whether eggs were cage-free or not had little effect on their CML and CEL levels, but raw and heated eggs from two different companies contained significantly different amounts of CML and CEL. Overall, egg whites are more susceptible to heating than egg yolks and severe thermal treatment should be avoided to reduce the contents of AGEs in egg whites.     

Two outbreaks of Salmonella enteritidis phage type 4 infection associated with the consumption of fresh shell-egg products

In 1988 there were two outbreaks of infection with Salmonella enteritidis phage type 4 in adjacent local authorities. The first affected 18 of 75 helpers and guests who attended a private function. Investigations revealed that home-made vanilla ice-cream containing uncooked eggs was the vehicle of infection and the causative organism was identified at the premises of the egg producer. The second affected 84 of 422 delegates attending a conference dinner, and 12 of 50 hotel staff at risk. A dessert made with lightly-cooked egg yolk and raw egg white was associated with infection, and the epidemic strain was cultured from the shell of an egg and an environmental sample from the producer's farm. It is of interest that one outbreak involved free-range and one battery-produced eggs, and that in one the vehicle was prepared at home and in the other in commercial premises. In neither incident was any deficiency in standards of egg production or catering practice discovered.     

Raw-fish-eating behavior and fishborne zoonotic trematode infection in people of northern Vietnam

Raw fish consumption in restaurants, for example, Sashimi style, is popular worldwide. In Vietnam, raw fish dishes are also traditionally prepared and consumed in private households. However, the habits of eating raw or otherwise inadequately cooked fish can be associated with risks of acquiring fishborne zoonotic trematode (FZT) infection. The present study was done in a fish-farming community in Nam Dinh, Vietnam, to obtain information about habits of eating raw fish dishes and risks for human FZT infection. Discussions were held in different groups divided by gender and age on raw-fish-eating behavior. A total of 180 household members were interviewed and their stool samples analyzed to identify risk factors of FZT infection. There was awareness about the risk of liver fluke infections from eating raw fish. However, many older people accepted these risks and continued eating raw fish, as they know effective drug treatment is available. Raw fish dishes are consumed at social gatherings from shared plates and dipping sauces using the same chop sticks. This is likely to pose risks of crosscontamination with FZT metacercariae to different food items as indicated by the finding that 25.8% of household members that stated not to have eaten raw fish were infected. In total, 32.2% fish farm household members were infected with FZT. The odds of FZT infection was 2.3 times higher (p?=?0.013) for those eating raw fish than for those who did not eat raw fish. Among the people eating raw fish, those eating raw fish in restaurants had 3.6 times higher odds of FZT infection (p?=?0.009) than people eating raw fish at home. A successful program to control FZT must be based on in-depth knowledge on the social and anthropological determinants of people's raw-fish-eating behavior and hygiene practices as well as production of FZT-free fish for human consumption.     

江苏省民间厨师食品卫生法KAP及影响因素

目的了解江苏省农村地区民间厨师的食品卫生和法制知识的认识、态度、行为（KAP）状况，探讨其影响因素。为卫生部门的监管工作提供依据。方法采用民间厨师食品卫生和法制KAP调查问卷，由经专门培训的调查员对568名民间厨师采取面对面访谈的方式进行调查。结果民间厨师从业时间与地区经济因素显著相关（R=0．605，P=0．000）；民间厨师食品卫生和法制知识知晓率、态度持有率、行为正确率分别为33．42％，83．80％，32．92％；多元逐步回归显示，KAP得分受民间厨师的性别、文化程度、年龄、从业时间、有无卫生培训证明、职业因素的影响（R=0．394，F=17．025。P=0．000）。结论目前江苏省民间厨师的食品卫生和法制知识以及个人卫生行为存在诸多问题，应加强对民间厨师的相关培训及管理。     

British eggs: Back on the menu for all

This article updates the latest guidance and research on the suitability of eggs as a good source of nutrition for particular population groups. This follows the publication of two important UK government reports: revised advice for vulnerable groups from the Food Standards Agency and a draft report about infant feeding from the Scientific Advisory Committee on Nutrition (SACN), as well as a recent review on egg consumption and cardiovascular disease risk in people with type 2 diabetes. The Food Standards Agency now advises that raw or lightly cooked British eggs are safe to eat for vulnerable groups, such as pregnant women, babies, toddlers and older people, provided that the eggs bear the Lion mark. This indicates that they have been produced under the British Lion Code of Practice, a scheme that includes more than 700 auditable criteria, of which vaccination of laying hens against Salmonella is a key aspect. The draft SACN report Feeding in the First Year of Life recommends that first complementary foods should be introduced from around 6 months of age and that there is no need to differentiate hens’ egg from other foods in this respect. There is also a warning that the deliberate exclusion or delayed introduction of allergenic foods including egg may increase the risk of allergy to these foods later in childhood. As regards people with type 2 diabetes, despite earlier concerns from epidemiological studies that higher egg intake might increase cardiovascular disease risk, more recent high‐quality intervention studies indicate that, provided eggs are consumed as part of a healthy, energy‐controlled diet, there is no need for concern. Eggs provide a wide range of important nutrients, including several that are found in only a limited number of other foods, such as vitamin D, iodine and the long‐chain omega‐3 fatty acid, docosahexaenoic acid. They are therefore a useful and versatile ingredient for pregnant women, infants and children, and older people.     

Phthalate Exposure in Pregnant Women: Risk Perception and Preventive Advice of Perinatal Health Professionals

Objectives The main objective of the PERI–HELPE study (Perception of Risk–HEaLth Professionals and Environment Study) was to describe the knowledge of perinatal health professionals about phthalates and the preventive advice they give to pregnant women about exposure to these chemicals. The secondary objective was to determine whether giving preventive advice was associated with the perception of phthalates. Methods A cross-sectional study was performed in 2015 in France. One hundred and eighty-nine perinatal health professionals (obstetricians, midwives and general practitioners) replied to an online self-administered questionnaire (participation rate: 11%). Results Only 17% of health professionals felt able to provide appropriate answers to pregnant women about phthalates. Advice was given by 23% (avoid plastic kitchen cling film) to 75% (prefer homemade dishes) about eating habits, by less than 42% for the use of cosmetics and less than 25% for that of consumer products. After adjusting for covariates, the awareness that pregnant women are daily exposed to phthalates (44% of professionals) was associated with dietary advice [avoid pre-packaged food (OR 2.2; 95% CI 1.1–4.4), prefer homemade dishes (OR 2.6; 95% CI 1.2–5.9) and avoid plastic kitchen cling film (OR 2.4; 95% CI 1.0–5.6)] but not with advice about cosmetics or consumer products. The perception of phthalate exposure as a high risk (66%) was not associated with preventive advice. Conclusions for Practice Our sample size was not very large but the findings nevertheless show the lack of knowledge of perinatal health professionals about phthalates. If they are to take on a preventive role, health professionals in France need to be better informed about phthalates and more fully trained in environmental health in general.

     

Contamination of hands and work surfaces with Salmonella enteritidis PT4 during the preparation of egg dishes.

Salmonella enteritidis PT4 was recovered from fingers following the breaking of intact shell eggs artificially contaminated in the contents with the bacterium. Kitchen utensils used to mix egg dishes were salmonella-positive, sometimes after washing. Following the preparation of batter or the mixing of eggs, S. enteritidis was recovered from work surfaces over 40 cm from the mixing bowl. The bacterium survived well in thin, dry films of either batter or egg and, from an initial level of one cell per cm2, could be recovered from formica work surfaces 24 h after contamination.     

Audit for the Heartbeat Award in staff catering facilities in an NHS Trust

Background: The Heartbeat Award Scheme (HBA) is a national initiative whereby caterers receive an award for meeting identified minimum criteria related to healthy menu choices, food hygiene and eating environment. The eligibility of four staff catering facilities in an NHS Trust was assessed by audit. Methods: An audit tool was developed which enabled comparison between food displayed and itemized on the menu board and HBA criteria for each food category. It also contained questions about food preparation and ingredients. The catering facilities were audited on five different weekdays during a 2-week period (seven for one facility). Observations were recorded about visibility, appearance and plate wastage. Results: Usually it was clear whether food served achieved HBA criteria, but development of quantified criteria were necessary for reliable assessment of main dishes, sandwiches and desserts. A summary of the key findings are presented, including achievement of HBA criteria, together with the resulting recommendations, observations and identification of issues arising from the audit. Conclusion: The benefits of this approach outweigh any drawbacks and include the ability to facilitate assessment for the HBA in the absence of written menus, obtain baseline information, enable repeated audit and provide details to support recommendations made to caterers. The audit tool has now been included as part of the contract specification for the local purchasing commission.     

Effect of fixed or changing temperatures during prolonged storage on the growth of Salmonella enterica serovar Enteritidis inoculated artificially into shell eggs

The fate of Salmonella enterica serovar Enteritidis (SE) in whole, unbroken eggs was monitored during storage at fixed or changing temperatures after inoculation with 20-47 c.f.u. of SE. Eggs stored at 10 degrees C and 20 degrees C showed little or no bacterial growth over 6 weeks, while egg storage at 30 degrees C increased the percentage of the eggs that contained >10(6) c.f.u. after 3 weeks. Egg storage at 20 degrees C for 5 days followed by 10 degrees C caused only a few eggs with >10(6) c.f.u. after 2 weeks, whereas storage at 22-30 degrees C or 27-35 degrees C for 5 days followed by 25 degrees C induced a rapid increase of eggs that contained >10(6) c.f.u. after 1 or 2 weeks, respectively. Therefore, egg storage at 10 degrees C and 20 degrees C can control SE growth, although the temperature during egg storage and transportation from farm to table should also be taken into consideration.     

Detection of a nosocomial outbreak of salmonellosis may be delayed by application of a protocol for rejection of stool cultures

In October 2001 an outbreak of Salmonella enterica serovar enteritidis phage-type 6 occurred in a hospital and a nursing home, both served by the same hospital kitchen. Five nursing home residents died during the outbreak. S. enteritidis was isolated from three of them. Of 231 stool samples from nursing home residents, hospital patients and employees, 82 were culture-positive. All symptomatic patients were treated with oral ciprofloxacin. Inspection of the kitchen showed that during preparation of the desserts implicated in causing the outbreak, temperatures were not measured and storage temperatures were too high. No left-over food samples were available for analysis. According to the 'four-day rule' in use in this hospital, the stool samples related to the first outbreak were not cultured for Salmonella spp., whereas culturing afterwards from both stored specimens and repeats, showed that some of these samples would have been positive for S. enteritidis. Thus without the application of stool culture rejection criteria the outbreak would have been detected one day earlier. With the four-day rule in effect, the outbreak might have been detected much later, if an unusually high number of nursing home residents with gastroenteritis had not been noticed by nursing home physicians. The rule was revised to prevent a possible delay in the future. As a result of this outbreak, the government has announced legislation forbidding the sale of Salmonella-contaminated eggs. An official ban on the use of raw eggs will be included in several hygiene codes.     

Incremental Costs and Diners’ Satisfaction Associated with Improvement in Nutritional Value of Catering Dishes

Eating in catering systems has been identified as a driver of poor diet quality. Interventions within catering systems increase the nutrient density of dishes. Little is known about the incremental costs associated with this strategy. One part of the NEKST (Nutrition Environmental Kibbutzim Study) intervention was nutritional improvement of recipes (decreasing the amount of energy, sodium, and saturated fat). We evaluated the nutritional content of dishes per 100 g and the incremental costs associated with these changes from the catering system’s perspective, as well as diners’ satisfaction with the catering system before and after the intervention. Our results revealed that as energy and saturated fat decreased, the associated incremental cost increased (rs = −0.593, p = 0.010 and rs = −0.748, p < 0.001, respectively). However, the decrease in sodium was not associated with increased costs (rs = 0.099, p = 0.696). While diners’ satisfaction decreased in the control group, it did not change in the intervention group following the intervention (p = 0.018). We concluded that recipe modification improved the nutritional value of dishes without increasing cost. This intervention was not associated with decreased diner satisfaction. This evidence encourages the implementation of policies to improve the nutritional quality of food served by caterers without jeopardizing sales and with the potential to improve public health.     

Stability of faecal egg excretion in Schistosoma mansoni infection

Stability of Schistosoma mansoni egg excretion was studied in 23 residents of a rural endemic area in North-east Brazil where the over-all prevalence rate was 87% and the peak geometric mean egg excretion was 308 eggs/ml (Bell method) in the 10 to 14-year-old age group. Stool examinations by the Kato method were performed for three to four consecutive days each month for three consecutive months. Both raw and transformed data showed significant stability of S. mansoni egg excretion from day to day and month to month in this population. A single Kato examination detected 68% of individuals who were excreting more than 400 eggs per gramme. Although S. mansoni egg excretion is stable over time, identifying individuals with high egg excretion in endemic populations requires sensitive quantitative methods.     

Food allergen avoidance: risk assessment for life

The skills and knowledge required to carry out food allergen avoidance are becoming increasingly sophisticated. It is not enough to know the names of a handful of dishes which contain a known allergen as an ingredient. Many lifestyles now depend on food prepared away from the home. New product development has introduced a wide range of ingredients and dishes which are labour saving, exciting and innovative. Product traceability now depends on advanced technological support as it struggles to keep up with foods manufactured, prepared and served in ever more complex circumstances. Consumers are now faced with 'a jungle of choices'. However, those individuals who need to avoid a known allergen, particularly in trace quantities, often find that the food choice deemed suitable is poor, and the information available inadequate or even dangerously misleading. There are two important groups for whom this situation is a major concern. Thousands of families with young children are forced to live with the possibility that everyday foods may be contaminated by a known allergen which could kill in minutes. They live on their nerves, reading every packet and resorting to hyperprotective childcare and vigilance. In addition, the youngest independent consumers, teenagers and those in their twenties, may have little first-hand experience of food preparation. They may be ill-equipped in food-allergen risk assessment. Sadly, those who die from anaphylaxis or allergen-triggered asthma are often in this age-group. Current initiatives to support consumers at risk include a recognised standard for manufacturers seeking to eliminate an allergen from their production, and the integration of food allergy into training for caterers and food standards enforcement professionals.