Microbiological food safety and a low-microbial diet to protect vulnerable people

Microbiological profiling and knowledge of food preservation technology to support guidance on a neutropenic diet for immunocompromised patients

The current society consists of an increasing number of people vulnerable to infections. For certain people with severe immunodeficiency, a neutropenic or low-microbial diet is being prescribed, which substitutes high-risk foods that are more likely to contain human (opportunistic) pathogens with lower-risk alternatives. These neutropenic dietary guidelines are typically set up from a clinical and nutritional perspective, rather than from a food processing and food preservation perspective. In this study, the current guidelines in use by the Ghent University Hospital were evaluated based on the current knowledge of food processing and preservation technologies and the scientific evidence on microbiological quality, safety, and hygiene of processed foods. Three criteria are identified to be important: (1) the microbial contamination level and composition; (2) the potential presence of established foodborne pathogens such as Salmonella spp. (to which a zero-tolerance policy is recommended); and (3) an increased vigilance for L. monocytogenes as an opportunistic foodborne pathogen with a high mortality rate in immunocompromised individuals (to which a zero-tolerance policy should apply). A combination of these three criteria was used as a framework for the evaluation of the suitability of foodstuffs to be included in a low-microbial diet. Differences in processing technologies, initial contamination of products, etc., however, lead to a high degree of variability in microbial contamination and make it difficult to unambiguously accept or reject a certain type of foodstuff without prior knowledge of the ingredients and the processing and preservation technologies applied during manufacturing and subsequent storage conditions. A restricted screening on a selection of (minimally processed) plant-based foodstuffs on the retail market in Flanders, Belgium supported decision-making on the inclusion of these food types in a low-microbial diet. Still, when determining the suitability of a foodstuff to be included in a low-microbial diet, not only the microbiological status but also nutritional and sensorial properties should be assessed, which requires multidisciplinary communication and collaboration.

Food safety in vulnerable populations: A perspective on the challenges and solutions

Vulnerable populations are a particular group that are not capable of fending for themselves due to a number of limitations. Among many things, of particular concern is the food safety challenges faced by these individuals and the high risk of susceptibility to foodborne diseases. In this paper, an attempt is made to point out the various challenges faced by vulnerable populations that make them more susceptible to foodborne illness than other healthy adults. Also, the paper highlights possible improvement pathways through which these people can have access to safe and nutritious food, and the current interventional steps taken to address the food safety risk associated with food handling activities of food meant for vulnerable groups.

Listeria monocytogenes Illness and Deaths Associated With Ongoing Contamination of a Multiregional Brand of Ice Cream Products, United States, 2010-2015

BACKGROUND

Frozen foods have rarely been linked to Listeria monocytogenes illness. We describe an outbreak investigation prompted by both hospital clustering of illnesses and product testing.

METHODS

We identified outbreak-associated listeriosis cases using whole-genome sequencing (WGS), product testing results, and epidemiologic linkage to cases in the same Kansas hospital. We reviewed hospital medical and dietary records, product invoices, and molecular subtyping results. Federal and state officials tested product and environmental samples for L. monocytogenes.

RESULTS

Kansas officials were investigating 5 cases of listeriosis at a single hospital when, simultaneously, unrelated sampling for a study in South Carolina identified L. monocytogenes in Company A ice cream products made in Texas. Isolates from 4 patients and Company A products were closely related by WGS, and the 4 patients with known exposures had consumed milkshakes made with Company A ice cream while hospitalized. Further testing identified L. monocytogenes in ice cream produced in a second Company A production facility in Oklahoma; these isolates were closely related by WGS to those from 5 patients in 3 other states. These 10 illnesses, involving 3 deaths, occurred from 2010 through 2015. Company A ultimately recalled all products.

CONCLUSIONS

In this US outbreak of listeriosis linked to a widely distributed brand of ice cream, WGS and product sampling helped link cases spanning 5 years to 2 production facilities, indicating longstanding contamination. Comprehensive sanitation controls and environmental and product testing for L. monocytogenes with regulatory oversight should be implemented for ice cream production.

Presence of Certain Foodborne Pathogens in Traditional Balearic Islands' Meat, Pastry, and Cheese Specialties Supported by European Union Quality Schemes, from 2018 to 2021

The cuisine of the Balearic Islands (Spain, southern Europe) has several products of a great tradition, recognized worldwide and covered by European Union quality schemes, such as Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI). Among them, the most emblematic products are sobrasada de Mallorca (a type of raw curated pork meat), ensaimada de Mallorca (pastry product), and Mahón-Menorca cheese (cow's milk cheese). During 4 consecutive years (2018-2021), the presence/absence of Escherichia coli β-glucuronidase positive (henceforth as E. coli), Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus in these products has been monitored, as well as the total yeast and mold count in ensaimada de Mallorca. The results of the microbiological analysis showed that sobrasada presented similar microbiological patterns to those of other raw curated meat products (some presence of E. coli and L. monocytogenes). Furthermore, the sobrasada de Mallorca made with white pork tended to be positive in E. coli compared to other sobrasada subtypes. In the case of ensaimada, only a reduced number of cases within filled ensaimadas (with higher moisture content) presented unacceptable mold and yeast counts (>500 colony-forming unit [CFU]/g). Finally, the Mahón-Menorca cheese presented a surprising microbiology pattern: higher E. coli contamination in the pasteurized milk cheese compared to its raw counterpart. This pattern was observed for all the years, being statistically significant in 2020. This study has detected good microbiological status in the three traditional products studied. However, worrisome issues in Good Hygienic Practices have been detected for some companies that produce pasteurized milk Mahón-Menorca cheese under the PDO quality label. The companies involved and even the competent authorities should address these problems to correct this deviation in food security.

Dietitians View of Foodservice Sanitary Practices and Demands in Long-Term Care Hospitals

This study aimed to investigate the current state of foodservice management and demands for improvement in long-term care hospitals. The survey was performed in experienced dietitians working at 25 hospitals. General characteristics, status of sanitary management (document management, self-assessment of importance and performance), necessity and ranking of sanitary management items were investigated. Approximately 2.5 dietitians worked in each hospital, but only 7 (28.0%) hospitals employed clinical dietitians. From the questionnaire, the scores of the importance in sanitary management and performance were 4.5 ± 0.7 and 4.3 ± 0.9, respectively, and were significantly different (p = 0.000). Participants also reported "special therapeutic diets management" and "compliance with standards of refrigerating time, food, method management" had the lowest importance and performance, respectively. The result of Importance-Performance Analysis revealed a significant positive correlation between importance and performance (R² = 0.427). However, items such as "performing hand hygiene" and "compliance with standards of refrigerating time, food, method" and etc. had low importance recognition with low performance. All participants reported "preparing sanitary management standards was necessary" is necessary and "development of sanitary management manual" is the most important. These findings suggest that sanitary management is important in food service management of long-term care hospitals, and improving awareness is required. Developing a hospital foodservice hygiene manual would ensure better safety and quality for patient care and public health.

Microbiological Safety of Dried Spices

Spices in the desiccated state provide an environment that allows the survival of many foodborne pathogens. Currently, the incidence of pathogen-positive spices imported into the United States is 1.9 times higher than for any other imported food. Correspondingly, imported spices have been associated with numerous foodborne outbreaks and multiple product recalls. Despite the association with recalls and outbreaks, the actual pathogen populations in spices, when found, are frequently extremely small. In addition to pathogenic bacterial species, toxigenic molds have been frequently recovered from spices, and aflatoxins have been found in as many as 58% of the spices sampled. The presence of toxigenic molds is especially problematic to the immunocompromised or those on immunosuppressive therapy and has been linked to gut aspergillosis. Numerous detection methods, including both traditional and advanced DNA regimes, are being tested to optimize recovery of pathogens from spices. Further, a number of new inactivation intervention methods to decontaminate spices are examined and discussed.

Low bacterial diet versus control diet to prevent infection in cancer patients treated with chemotherapy causing episodes of neutropenia

BACKGROUND

Neutropenia is a potentially serious side effect of chemotherapy and a major risk factor for infection, which can be life-threatening. It has been hypothesised that a low bacterial diet (LBD) can prevent infection and (infection-related) mortality in cancer patients receiving chemotherapy that causes episodes of neutropenia, but much remains unclear. This review is an update of a previously published Cochrane review.

OBJECTIVES

The primary objective of this review was to determine the efficacy of an LBD versus a control diet in preventing infection and in decreasing (infection-related) mortality in adult and paediatric cancer patients receiving chemotherapy that causes episodes of neutropenia. Secondary objectives were to assess time to first febrile episode, need for empirical antibiotic therapy, diet acceptability and quality of life.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 4), the Database of Abstracts of Reviews of Effects (DARE) (2015, Issue 4), PubMed (from 1946 to 4 May 2015), EMBASE (from 1980 to 4 May 2015) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (from 1981 to 4 May 2015).In addition, we searched the reference lists of relevant articles and conference proceedings of American Society of Hematology (ASH; from 2000 to 2015), European Bone Marrow Transplantation (EBMT; from 2000 to 2015), Oncology Nurses Society (ONS; from 2000 to 2015), International Society for Paediatric Oncology (SIOP; from 2000 to 2014), Multinational Association of Supportive Care in Cancer (MASCC; from 2000 to 2015), American Society of Clinical Oncology (ASCO; from 2000 to 2015), Interscience Conference of Antimicrobial Agents and Chemotherapy (ICAAC; from 2000 to 2015), European Society for Clinical Nutrition and Metabolism (ESPEN; from 2000 to 2015), American Society for Parenteral and Enteral Nutrition (ASPEN; from 2000 to 2015) and European Hematology Association (EHA; from 2000 to 2015). In May 2015, we scanned the National Institutes of Health Register via clinicaltrials.gov and the International Standard Randomised Controlled Trial Number (ISRCTN) Register (www.controlled-trials.com).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing use of an LBD versus a control diet with regard to infection rate, (infection-related) mortality, time to first febrile episode, need for empirical antibiotic therapy, diet acceptability and quality of life in adult and paediatric cancer patients receiving chemotherapy causing episodes of neutropenia.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, 'Risk of bias' assessment and data extraction. We performed analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

In the original version of this review, we identified three RCTs that assessed different intervention and control diets in 192 participants (97 randomised to intervention diet; 95 to control diet) with different types of malignancies. For the update, we identified no eligible new studies. Co-interventions (e.g. protective environment, antimicrobial prophylaxis, central venous catheter care, oral care, hygiene practices, colony-stimulating factors) and outcome definitions also differed between studies. In all included studies, it was standard policy to give empirical antibiotics (and sometimes also antimycotics) to (some of) the participants diagnosed with an infection. Two studies included adults and one study included children. In all studies, only a scant description of treatment regimens was provided. All studies had methodological limitations. Pooling of results of included studies was not possible. In two individual studies, no statistically significant differences in infection rate were identified between intervention and control diets; another study showed no significant differences between treatment groups in the number of chemotherapy cycles with an infection. None of the studies mentioned infection-related mortality, but in one study, no significant difference in overall survival was observed between treatment groups. Time from onset of neutropenia to fever, duration of empirical antibiotics and antimycotics, diet acceptability (i.e. following the diet easily and following the diet throughout all chemotherapy cycles) and quality of life were all evaluated by only one study; for all outcomes, no statistically significant differences between treatment arms were identified.

AUTHORS' CONCLUSIONS

At the moment, no evidence from individual RCTs in children and adults with different malignancies underscores use of an LBD for prevention of infection and related outcomes. All studies differed with regard to co-interventions, outcome definitions and intervention and control diets. As pooling of results was not possible, and as all studies had serious methodological limitations, we could reach no definitive conclusions. It should be noted that 'no evidence of effect', as identified in this review, is not the same as 'evidence of no effect'. On the basis of currently available evidence, we are not able to provide recommendations for clinical practice. Additional high-quality research is needed.

Microbiological Food Safety for Vulnerable People

Foodborne pathogens are more likely to cause infection and to result in serious consequences in vulnerable people than in healthy adults. People with some increase in susceptibility may form nearly 20% of the population in the UK and the USA. Conditions leading to increased susceptibility are listed. The main factors leading to foodborne disease caused by major pathogens are outlined and examples are given of outbreaks resulting from these factors. Measures to prevent foodborne disease include procedures based on Hazard Analysis Critical Control Point principles and prerequisite programmes and, especially for vulnerable people, the use of lower-risk foods in place of higher-risk products.

A possible route for foodborne transmission of Clostridium difficile?

Spores of toxigenic Clostridium difficile and spores of food-poisoning strains of Clostridium perfringens show a similar prevalence in meats. Spores of both species are heat resistant and can survive cooking of foods. C. perfringens is a major cause of foodborne illness; studies are needed to determine whether C. difficile transmission by a similar route is a cause of infection.