Alexandre Lamas

Egg and Egg-Derived Foods: Effects on Human Health and Use as Functional Foods.

Eggs are sources of protein, fats and micronutrients that play an important role in basic nutrition. However, eggs are traditionally associated with adverse factors in human health, mainly due to their cholesterol content. Nowadays, however, it is known that the response of cholesterol in human serum levels to dietary cholesterol consumption depends on several factors, such as ethnicity, genetic makeup, hormonal factors and the nutritional status of the consumer. Additionally, in recent decades, there has been an increasing demand for functional foods, which is expected to continue to increase in the future, owing to their capacity to decrease the risks of some diseases and socio-demographic factors such as the increase in life expectancy. This work offers a brief overview of the advantages and disadvantages of egg consumption and the potential market of functional eggs, and it explores the possibilities of the development of functional eggs by technological methods.

Biofilm formation, phenotypic production of cellulose and gene expression in Salmonella enterica decrease under anaerobic conditions.

Salmonella enterica subsp. enterica is one of the main food-borne pathogens. This microorganism combines an aerobic life outside the host with an anaerobic life within the host. One of the main concerns related to S. enterica is biofilm formation and cellulose production. In this study, biofilm formation, morphotype, cellulose production and transcription of biofilm and quorum sensing-related genes of 11 S. enterica strains were tested under three different conditions: aerobiosis, microaerobiosis, and anaerobiosis. The results showed an influence of oxygen levels on biofilm production. Biofilm formation was significantly higher (P<0.05) in aerobiosis than in microaerobiosis and anaerobiosis. Cellulose production and RDAR (red, dry, and rough) were expressed only in aerobiosis. In microaerobiosis, the strains expressed the SAW (smooth and white) morphotype, while in anaerobiosis the colonies appeared small and red. The expression of genes involved in cellulose synthesis (csgD and adrA) and quorum sensing (sdiA and luxS) was reduced in microaerobiosis and anaerobiosis in all S. enterica strains tested. This gene expression levels were less reduced in S. Typhimurium and S. Enteritidis compared to the tested serotypes. There was a relationship between the expression of biofilm and quorum sensing-related genes. Thus, the results from this study indicate that biofilm formation and cellulose production are highly influenced by atmospheric conditions. This must be taken into account as contamination with these bacteria can occur during food processing under vacuum or modified atmospheres.

Biofilm Formation and Morphotypes of Salmonella enterica subsp. arizonae Differs from Those of Other Salmonella enterica Subspecies in Isolates from Poultry Houses

Salmonella serovars are responsible for foodborne diseases around the world. The ability to form biofilms allows microorganisms to survive in the environment. In this study, 73 Salmonella strains, belonging to four different subspecies, were isolated from poultry houses and foodstuffs and tested. Biofilm formation was measured at four different temperatures and two nutrient concentrations. Morphotypes and cellulose production were evaluated at three different temperatures. The presence of several genes related to biofilm production was also examined. All strains and subspecies of Salmonella had the ability to form biofilms, and 46.57% of strains produced biofilms under all conditions tested. Biofilm formation was strain dependent and varied according to the conditions. This is the first study to analyze biofilm formation in a wide number of Salmonella enterica subsp. arizonae strains, and no direct relationship between the high prevalence of Salmonella enterica subsp. arizonae strains and their ability to form biofilm was established. Morphotypes and cellulose production varied as the temperature changed, with 20°C being the optimum temperature for expression of the red, dry, and rough morphotype and cellulose. Salmonella enterica subsp. arizonae, whose morphotype is poorly studied, only showed a smooth and white morphotype and lacked the csgD and gcpA genes that are implicated in biofilm production. Thus, Salmonella biofilm formation under different environmental conditions is a public health problem because it can survive and advance through the food chain to reach the consumer.

Phytanic acid consumption and human health, risks, benefits and future trends: A review

Phytanic acid is a methyl-branched fatty acid present in the human diet, derived from the enzymatic degradation of phytol and subsequently oxidized by the rumenal microbiota and certain marine organisms. Consequently, phytanic acid is carried into the human body by means of food ingestion, mostly via red meat, dairy products and fatty marine foods. This fatty acid accumulates in people with some peroxisomal disorders and is traditionally related to neurological damage. However, some benefits derived from phytanic acid intake have also been described, such as the prevention of metabolic syndrome or type 2 diabetes. The aim of this work was to conduct an overview of the literature on the phytanic acid content of foods, management of the phytanic content during food production and biochemical mechanisms of phytanic acid metabolism, as well as to assess the evidence for the health benefits and risks of phytanic acid consumption in human health.

A comprehensive review of non- enterica subspecies of Salmonella enterica

Salmonella is a major foodborne pathogen with a complex nomenclature. This genus is composed of two species, S. enterica and S. bongori. S. enterica is divided into six subspecies. S. enterica subspecies enterica is composed of more than 1500 serotypes with some of great importance, such as S. Typhimurium and S. Enteritidis. S. enterica subsp. enterica is responsible of more than 99% of human salmonellosis and therefore it is widely studied. However, the non-enterica subspecies of S. enterica have been little studied. These subspecies are considered to be related to cold-blooded animals and their pathogenicity is very limited. Phenotype and genotype information generated from different studies of non-enterica subspecies reveal poor ability to invade host cells and the absence or modification of important virulence factors. Also, the great majority of human infections due to non-enterica subspecies are related to a previous depressed immune system. Therefore, we propose to treat these subspecies only as opportunistic pathogens. For establish this premise, the present review evaluated, among other things, the genomic characteristics, prevalence, antimicrobial resistance and reported human cases of the non-enterica subspecies.

An Evaluation of Alternatives to Nitrites and Sulfites to Inhibit the Growth of Salmonella enterica and Listeria monocytogenes in Meat Products

In recent years, the use of nitrites and sulfites as food preservatives has been a cause for concern due to the health problems that these additives can cause in humans. Natural products have been studied as an alternative, but most of them have hardly been applied in the food industry for technological and economic reasons. In this sense, organic salts such as sodium acetate are a good alternative due to their affordability. Thus, this study evaluated the capacity of sodium nitrite, sodium sulfite, a sodium acetate product (TQI C-6000), and chitosan to inhibit two important foodborne pathogens, Salmonella enterica and Listeria monocytogenes. The MIC of each chemical was in vitro evaluated and their antibacterial action was subsequently checked in situ using minced meat as a food model. MIC values of sodium nitrite (10,000 mg/L) and sodium sulfite (50,000 mg/L) for Salmonella enterica were higher than the values allowed by legislation (450 mg/L for sulfites and 150 mg/L for nitrites). Additionally, the sodium acetate product caused the inhibition of Salmonella enterica and Listeria at a relative low quantity. The two foodborne pathogens were inhibited in the food model with 1% of the sodium acetate product. Additionally, there were no significant differences between sodium nitrite, sodium sulfite, and sodium acetate products in the inhibition of Salmonella enterica and Listeria monocytogenes in the food model. Thus, products based on sodium acetate can be an alternative to traditional preservatives in food products.

Technological development of functional egg products by an addition of n-3 polyunsaturated-fatty-acid-enriched oil

Eggs are good candidates to be employed as functional food and to provide people with bioactive compounds such as n-3 PUFAs. However, in most cases, development of eggs with high content of n-3 PUFAs was carried out by modifying the hens’ feed. In the present work, egg-derived sticks with high content of n-3 PUFAs were technologically developed through addition of three different sources of n-3 PUFAs: linseed oil, fish oil and microalgae oil. The developed products were compared to conventional egg-derived products for their proximate composition, fatty acid profile, colour and consumer acceptability. Additionally, lipid oxidation was investigated after 30 days of frozen storage. Nutritional composition, colour parameters and consumer acceptability revealed that egg-derived product obtained by addition of linseed oil was the most adequate. Egg-derived functional foods developed by technological methods are viable and could be considered as an interesting alternative, especially for catering companies.

Salmonella and Campylobacter biofilm formation: a comparative assessment from farm to fork

It takes several steps to bring food from the farm to the fork (dining table), and contamination with food-borne pathogens can occur at any point in the process. Campylobacter spp. and Salmonella spp. are the main microorganisms responsible for foodborne disease in the EU. These two pathogens are able to persist throughout the food supply chain thanks to their ability to form biofilms. Owing to the high prevalence of Salmonella and especially of Campylobacter in the food supply chain and the huge efforts of food authorities to reduce these levels, it is of great importance to fully understand their mechanisms of persistence. Diverse studies have evaluated the biofilm-forming capacity of foodborne pathogens isolated at different steps of food production. Nonetheless, the principal obstacle of these studies is to reproduce the real conditions that microorganisms encounter in the food supply chain. While there are a wide number of Salmonella biofilm studies, information on Campylobacter biofilms is still limited. A comparison between the two microorganisms could help to develop new research in the field of Campylobacter biofilms. Therefore, this review evaluates relevant work in the field of Salmonella and Campylobacter biofilms and the applicability of the data obtained from these studies to real working conditions.

Tracing (r)bST in cattle: Liquid-based options for extraction and separation

ABSTRACT Growth hormone (GH) or somatotropin (ST) is a species-specific polypeptide hormone produced in the pituitary gland of vertebrates. When administered exogenously to dairy cattle, it has galactopoietic effects and is capable of increasing the milk yield. The beginning of the commercial production of recombinant variants of bovine somatotropin (rbST), by the end of the 20th century, had a major economic impact in the dairy industry. Recombinant bST enabled large-scale applications in farms, enhancing significantly milk production. While it is banned in the European Union (EU), several countries permit the trade and use of recombinant somatotropins in animal husbandry. Also, rbST-free dairy products can be frequently found in the market of those countries, even though these labels are not actually verified in a laboratory. In this context, effective analytical methods are needed for residue control to avoid an illegal use of rbST but also to prevent fraudulent labeling in some cases. The present review includes studies published in the last 5 years (from 2012 to 2017) to monitor rbST in bovine animals, using liquid-based applications. It is then intended to serve as a practical guide to help those laboratories interested in developing analytical methods to detect rbST use and abuse. GRAPHICAL ABSTRACT

Effect of Food Residues in Biofilm Formation on Stainless Steel and Polystyrene Surfaces by Salmonella enterica Strains Isolated from Poultry Houses

Salmonella spp. is a major food-borne pathogen around the world. The ability of Salmonella to produce biofilm is one of the main obstacles in reducing the prevalence of these bacteria in the food chain. Most of Salmonella biofilm studies found in the literature used laboratory growth media. However, in the food chain, food residues are the principal source of nutrients of Salmonella. In this study, the biofilm formation, morphotype, and motility of 13 Salmonella strains belonging to three different subspecies and isolated from poultry houses was evaluated. To simulate food chain conditions, four different growth media (Tryptic Soy Broth at 1/20 dilution, milk at 1/20 dilution, tomato juice, and chicken meat juice), two different surfaces (stainless steel and polystyrene) and two temperatures (6 °C and 22 °C) were used to evaluate the biofilm formation. The morphotype, motility, and biofilm formation of Salmonella was temperature-dependent. Biofilm formation was significantly higher with 1/20 Tryptic Soy Broth in all the surfaces and temperatures tested, in comparison with the other growth media. The laboratory growth medium 1/20 Tryptic Soy Broth enhanced biofilm formation in Salmonella. This could explain the great differences in biofilm formation found between this growth medium and food residues. However, Salmonella strains were able to produce biofilm on the presence of food residues in all the conditions tested. Therefore, the Salmonella strain can use food residues to produce biofilm on common surfaces of the food chain. More studies combining more strains and food residues are necessary to fully understand the mechanism used by Salmonella to produce biofilm on the presence of these sources of nutrients.