Santos García

Autonomous University of Nuevo León | UANL · Facultad de Ciencias Biológicas

Phenolic compounds (PC) affect many metabolic processes of microbes; however, there is no information about their effectiveness when these act in combination with low temperatures for the control of Escherichia coli pathotypes. In this study, four PC, (tannic acid [TA], gallic acid [GA], methyl gallate [MG], and epigallocatechin gallate [EG]) in co...

The AcrAB-TolC efflux pump (EP) confers multidrug resistance to Salmonella enterica, a major etiological agent of foodborne infections. Phytochemicals that inhibit the functions of AcrAB-TolC EP present ideal candidates for reversal of antibiotic resistance. Progressive technological advancements, have facilitated the development of computational m...

Cantaloupe melons, which have been responsible of an increasing number of foodborne disease outbreaks, may become contaminated with microbial pathogens during production. However, little information is available on the microbial populations in the cantaloupe farm environment. The purpose of this work was to characterize the bacterial communities pr...

Campylobacter frequently contaminates chicken. Trisodium phosphate (TSP) is used for chicken decontamination; however, reduction of chemical preservatives is desirable. This study analyzed the efficacy of two commercial citrus‐based products (CitroSan [CS] and Citrol‐K Ultra [CK]) alone and in combination with TSP for reduction of Campylobacter in...

Clostridium perfringens forms biofilms and spores that are a source of food contamination. In this study, the antibacterial activities of Lactobacillus plantarum culture supernatants (LP-S), LP-S fractions, and the plant-derived compound epigallocatechin gallate (EG) were evaluated. Specifically, their effects on the viability and biofilm-forming a...

Adherence of bacteria to the human intestinal mucosa can facilitate their internalization and the development of pathological processes. Escherichia coli O104:H4 is considered a hybrid strain (enteroaggregative hemorrhagic E. coli [EAHEC]), sharing virulence factors found in enterohemorrhagic (EHEC), and enteroaggregative (EAEC) E. coli pathotypes....

Cantaloupes contaminated with pathogens have led to many high-profile outbreaks and illnesses. Since bacterial virulence genes (VGs) can act in tandem with antibiotic-resistance and mobile genetic elements, there is a need to evaluate these gene reservoirs in fresh produce, such as cantaloupes. The goal of this study was to assess the distribution...

Shiga-toxin-producing Escherichia coli strains are pathogenic for humans and cause mild to severe illnesses. In this study, the antimicrobial effect of citral, eugenol, and hexanal in combination with heat shock (HS) was evaluated in terms of the growth, biofilm formation, swarming, and expression of virulence genes of STEC serotypes (O157:H7, O103...

Clostridium perfringens (formerly described as Bacillus aerogenes capsulatus, Bacillus perfringens, Bacillus welchii, or Clostridium welchii) is a natural inhabitant of soil and the intestinal tracts of many warm-blooded animals, including humans, and it is the most prolific toxin-producing species within the clostridial group. The ubiquitous natur...

Non-alcoholic fatty liver disease (NAFLD) is a manifestation of metabolic syndrome closely linked to dyslipidemia and gut microbiome dysbiosis. Bilberry anthocyanins (BA) have been reported to have preventive effects against metabolic syndrome. This study aimed to investigate the protective effects and mechanisms of BA in a Western diet (WD)-induce...

Little information is available regarding the pathogens that cause diarrhea in hospitalized patients who also have various clinical problems. The purpose of this study was to determine the presence of pathogens in fecal samples of hospitalized patients all suffering diarrhea in addition to other problems in Mexico. Diarrheic stools from 240 patient...

This study demonstrated that the type of produce commodity handled influences the ability of handwashing with soap and water or a two-step alcohol-based hand sanitizer (ABHS) intervention to reduce soil and bacterial hand contamination. Handwashing with soap and water, as recommended by the FDA’s Produce Safety Rule, when tested in three agricultur...

More efficient sampling and detection methods of pathogens on fresh produce are needed. The purpose of this study was to compare a novel rinse/membrane filtration method (RMFM) to a more traditional sponge rubbing or stomaching method in processing jalapeño peppers and cantaloupe samples for detection of Escherichia coli , Salmonella enterica , and...

Most Escherichia coli strains are innocuous to human beings; however, some strains can cause diarrhea and are grouped into pathotypes. Since current trends promote the use of natural-origin compounds to control bacteria, in this study, the effects of the phenolic compounds (PCs) tannic acid (TA), gallic acid (GA), methyl gallate (MG), and epigalloc...

Increased interest in providing safe food with excellent quality and shelf-life has resulted in increased efforts toward developing new bio-based packaging materials. The objectives of this study were to develop and characterize films based on linseed mucilage (LM) at concentrations of 2.0%, 2.5%, and 3.0% and the further development of antimicrobi...

Significant progress has been made in the last few years towards our understanding of the epidemiology, pathogenicity, and control of foodborne disease, including food poisoning, caused by Clostridium perfringens strains. Despite this, a significant burden of food poisoning illnesses still occurs in the United States every year, with nearly a milli...

In order to determine the microbial safety of produce, conventional fecal indicator bacteria (CFIB) such as Escherichia coli and Enterococcus are quantified as a standard practice. Bacteroidales are also fecal indicators mostly used for water samples; however, their use and persistence in foods has been rarely studied. In this study, persistence of...

The most commonly used indicator of fecal contamination in fresh produce production and packing is Escherichia coli. In depth analysis of the prevalence and characteristics of naturally occurring E. coli strains in these environments is important because it can (1) serve as an indicator of sources of fecal contamination; and (2) provide information...

Chihuahua cheese is a traditional cheese produced in Northwest Mexico that is consumed shortly after production. Cheeses prepared during autumn, winter and summer were collected from five dairies, and analyzed to determine seasonal influence on proximate analysis, texture profile and the microbiological dynamic during a ripening period of 270 days....

Nopal cacti (Opuntia spp.) are important natural resources in semi-arid zones throughout the world, where their fruits and stems are used as forage or human food depending on the variety and ripeness of the cladode. Members of the genus Opuntia show variable phytochemical composition as well as a high capacity for adaptation to extreme environmenta...

Most methods that investigate fecal contamination of vegetables do not address the origin of contamination. Because host-specific sequences are conserved in their genomes, bacteria of the order Bacteroidales are regarded as alternative indicators for tracking sources of contamination of produce. The objective of this study was to determine the effi...

Visible soil on farmworker hands has been assumed to indicate microbial contamination that may lead to contamination of produce and illness in the consumer. To test this assumption, we assessed the relationship of visible soil with microbial load on farmworker hands. 78 farmworkers harvested tomatoes for 30 minutes, practiced hand hygiene (hand was...

Food-producing animals are the major reservoirs for many foodborne pathogens such as Campylobacter species, non-Typhi serotypes of Salmonella enterica, Shiga toxin-producing strains of Escherichia coli, and Listeria monocytogenes. The zoonotic potential of foodborne pathogens and their ability to produce toxins causing diseases or even death are su...

Visible soil on farmworker hands has been assumed to indicate microbial contamination that may lead to contamination of produce and illness in the consumer. To test this assumption, we assessed the relationship of visible soil with microbial load on farmworker hands. 78 farmworkers harvested tomatoes for 30 minutes, practiced hand hygiene (hand was...

Background Chlamydia trachomatis is the causative agent of the most common bacterial sexually transmitted infection worldwide. The aim of this study was to investigate the frequency and genotypes of C. trachomatis in patients attending an obstetrics and gynecology clinic in Jalisco, Mexico and correlates them with sociodemographic, behavioral, and...

Food handlers are important sources of contamination in the agricultural environment. This study was conducted (i) to evaluate the activity of antimicrobial soaps against Escherichia coli and Enterococcus faecalis using a hand washing model with soiled hands and (ii) to determine the survival and persistence of these bacteria in rinsates. Sterilize...

Samples of artisanal Chihuahua cheese were collected in autumn, winter and summer from five farms from Chihuahua State, Mexico; temperature, pH and processing times were also recorded. Indicator microorganisms as well as lactic acid bacteria were determined. Samples were negative for Salmonella sp., and, except for coliforms, the particular season...

Edible coatings (ECs) based on chitosan (CH), pullulan (PU), linseed (LM), nopal cactus (NM) and aloe mucilage (AM) were applied by layer-by-layer technique to preserve the quality and prolong the shelf-life of fresh-cut pineapple. Pineapples were washed, disinfected, dried and cut into 2 cm side cubes. Fresh-cut fruit was coated by dipping using f...

Fruit and vegetable consumption has been widely accepted as an integral component of a healthy diet. A diet including more fresh fruit and vegetables has been achieved due to more availability, diversity, affordability, international trade, electronic communication, urbanization, improved transportation, public education and healthy trends, and imp...

Adherence and invasion to cells are the key processes during infection development by Campylobacter jejuni (C. jejuni). In this study, extracts from the byproducts of Citrus limon, Citrus aurantium, and Citrus medica were added to the cultures of C. jejuni, and the adherence and invasion of C. jejuni to HeLa cells and the expression of cadF and cia...

To improve food safety on farms, it is critical to quantify the impact of environmental microbial contamination sources on fresh produce. However, studies are hampered by difficulties achieving study designs with powered sample sizes to elucidate relationships between environmental and produce contamination. Our goal was to quantify, in the agricul...

Bacterial metabolites with communicative functions could provide protection against stress conditions to members of the same species. Yet, information remains limited about protection provided by metabolites in Bacillus cereus and inter-species. This study investigated the effect of extracellular compounds derived from heat shocked (HS) and non-HS...

Mycotoxins are secondary metabolites produced by specific filamentous fungi that are common contaminants of agricultural commodities. These compounds are toxic to humans and animals, and they are a health problem worldwide. Mycotoxin-containing feeds can cause serious diseases in farm animals and substantial economic losses. Therefore, the objectiv...

Sexually transmitted infections (STIs) are caused by more than 30 species; the organisms with the highest frequency and clinical importance are Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, Mycoplasma genitalium, the hepatitis B and C viruses, the human immunodeficiency virus, the human papillomavirus, the herpes simplex virus t...

Somatic coliphages were quantified in 459 produce and environmental samples from 11 farms in Northern Mexico to compare amounts of somatic coliphages among different types of fresh produce and environmental samples across the production steps on farms. Rinsates from cantaloupe melons, jalapeño peppers, tomatoes, and the hands of workers, soil, and...

Objective: To determine the frequency of nine sexually transmitted pathogens, coinfections and risk factors in patients attending obstetrics and gynecology clinics in Jalisco, Mexico. Materials and methods: Samples from 662 patients attending obstetrics and gynecology clinics were analyzed. Treponema pallidum, HIV, and HCV were detected by serol...

The purpose of this study was to determine the effects of plant products on the growth, swarming motility, biofilm formation and virulence gene expression in enterohemorrhagic Escherichia coli O157: H7 and enteroaggregative E. coli strain 042 and a strain of O104: H4 serotype. Extracts of Lippia graveolens and Haematoxylon brassiletto, and carvacro...

To prevent fresh produce-associated outbreaks, effective hand hygiene is critical, although determining the effectiveness of hand hygiene interventions in the agricultural environment has not been well studied. The primary purpose of this study was to compare the effect of two hand hygiene interventions on the concentrations and presence of soil (A...

Effective hand hygiene is essential to prevent the spread of pathogens on produce farms and reduce foodborne illness. The U.S. Food and Drug Administration Food Safety Modernization Act Proposed Rule for Produce Safety recommends the use of soap and running water for hand hygiene of produce handlers. The use of alcohol-based hand sanitizer (ABHS) m...

Edible active coatings (EACs) based on pectin, pullulan, and chitosan incorporated with sodium benzoate and potassium sorbate were employed to improve the quality and shelf life of strawberries. Fruits were washed, disinfected, coated by dipping, packed, and stored at 4 °C for 15 d. Application of EACs reduced (P < 0.05) weight loss and fruit softe...

Several methods have been described to prepare fresh produce samples for microbiological analysis, each with its own advantages and disadvantages. The aim of this study was to compare the performance of a novel combined rinse and membrane filtration method to two alternative sample preparation methods for the quantification of indicator microorgani...

Pantoea vagans is an opportunistic pathogen for humans. This organism is frequently isolated from various horticultural commodities. Active compounds from some essential oils have been used to control food-borne pathogens. The objectives of this investigation were to determine the effect of four active constituents of essential oils on the morpholo...

RESUMEN La carne es una matriz rica en nutrientes que proporciona un entorno adecuado para la proliferación de diversos microorganismos, deteriorantes y patógenos. Dentro de estos últimos se encuentra E. coli O157 y no‐O157, Salmonella spp. y Listeria monocytogenes. Por otro lado, la creciente demanda de productos " similares a los frescos " con ca...

RESUMEN La carne es una matriz rica en nutrientes que proporciona un entorno adecuado para la proliferación de diversos microorganismos, deteriorantes y patógenos. Dentro de estos últimos se encuentra E. coli O157 y no‐O157, Salmonella spp. y Listeria monocytogenes. Por otro lado, la creciente demanda de productos " similares a los frescos " con ca...

Parsley (Petroselinum crispum-Apiaceae) has been reported as a vehicle for Salmonella and E. coli O157:H7; and Shigella sonnei has been responsible for shigellosis outbreaks. Plant-derived extracts have been proposed as alternatives to reduce food contamination without modifying food properties, and several extracts have decreased pathogenic bacter...

Brominated furanone and epigallocatechin gallate (EGCG) are naturally occurring polyphenolic compounds that can be derived from sources such as Delisea pulchra algae and green tea, respectively. These compounds may have potential health benefits and antimicrobial properties. Biofilm formation and bacterial motility are virulence factors that seem t...

Quorum Sensing (QS), a signaling system present in bacteria, influences the expression of a variety of virulence factors. This study investigated the ability of citrus extracts to inhibit the activity of AI-2 molecules that mediate QS in Campylobacter jejuni and the effects of these extracts on motility, biofilm formation and expression of flaA-B....

The antimicrobial and antioxidant activities of some cultivars of the nopal cactus have not been determined. In this study, 8 cultivars of nopal cacti from Mexico were assayed for phenolic content, antioxidant activities, and antimicrobial activities against Campylobacter Jejuni, Vibrio cholera, and Clostridium Perfringens. Plant material was washe...

In recent decades, fresh and minimally processed produce items have been associated with an increasing proportion of food-borne illnesses. Most pathogens associated with fresh produce are enteric (fecal) in origin, and contamination can occur anywhere along the farm-to-fork chain. Microbial source tracking (MST) is a tool developed in the environme...

Introduction: Although produce associated outbreaks are a serious public health burden, few studies have characterized contamination routes or points in the production process where contamination has occurred. Thus, we aim to: 1) quantify contamination by fecal indicators on produce and farm workers' hands at different points in the chain of events...

The antimicrobial activity of Acacia farnesiana against V. cholerae has been demonstrated; however, no information regarding its active compound or its mechanism of action has been documented. The active compound was isolated from A. farnesiana by bioassay-guided fractionation and identified as methyl gallate by nuclear magnetic resonance (NMR) tec...

The source of a large outbreak of foodborne disease related to Salmonella-contaminated jalapeño peppers has been traced to Nuevo Leon, Mexico. The objective of this work was to evaluate the microbiological quality of tomatoes and jalapeño peppers from markets and supermarkets from the metropolitan area of Monterrey, Nuevo León, Mexico. One hundred...

Campylobacter, found in the intestinal microbiota of a large number of wild and domestic animals, is currently recognized as the most frequent foodborne pathogen and remains one of the most prevalent bacterial foodborne pathogens in the industrial world to date. Campylobacteriosis, the acute gastrointestinal illness caused by several Campylobacter...

Aflatoxins, produced primarily by the fungi Aspergillus flavus and Aspergillus parasiticus on agricultural commodities, are by far the best-characterized class of mycotoxin. In addition to aflatoxins, A. flavus produces a number of other minor mycotoxins. These include cyclopiazonic acid, which is an indole-tetramic acid found as a natural contamin...

Unlabelled: Fresh cilantro, parsley, and spinach are products that are regularly consumed fresh, but are difficult to decontaminate, as a result, they are common vehicles of transmission of enteropathogenic bacteria. In this study, the efficacy of plant extracts as alternatives for disinfection of cilantro, parsley, and spinach that were artificia...

Biofilms allow bacteria to adhere to biological or nonbiological surfaces and are difficult to remove, whereas swarming enables the rapid colonization of nutrient-rich environments. In this study, the efficacy of six commercial citric-based antimicrobial formulations to control growth, biofilm production, and swarming of Salmonella was determined....

The effectiveness of the 3M™ Petrifilm™ aerobic count plate for determining the amount of Bacillus sporothermodurans and Geobacillus stearothermophilus in ultra high temperature milk was determined and its efficacy was compared with the pour-plate agar and one-streak nutrient agar methods. Tubes containing milk were inoculated with spore suspension...

The prevalence and antimicrobial resistance of Salmonella serotypes on beef carcasses from four small abattoirs in Jalisco State, Mexico, were investigated during a 10-month period. Following U.S. Department of Agriculture Food Safety and Inspection Service protocols, Salmonella was isolated from 78 (15.4%) beef carcasses (n = 505) after the final...

Many fresh produce items including melons, parsley, onions, tomatoes and jalapeño and serrano peppers, have been linked to outbreaks of microbial disease. Little is known about the quality of fresh produce in the northern part of Mexico. Monterrey, situated in northeast Mexico, is the third largest city in the country, with a population of about fo...

Although farms and packing sheds have been implicated in several outbreaks caused by contaminated produce, contamination routes are not well understood. To address this, we completed two epidemiological field studies in farms and packing sheds on the US-Mexico border. In May, we pilot tested a novel study design in Mexico, to build on our past work...

Unlabelled: Campylobacter spp. is recognized as one of the most common cause of food-borne bacterial gastroenteritis in humans. Campylobacter infection causes campylobacteriosis, which can range from asymptomatic to dysentery-type illnesses with severe complications, such as Guillian-Barre syndrome. Epidemiological studies have revealed that consu...

Clostridium perfringens is a spore-forming bacterium and natural inhabitant of soil and the intestinal tracts of many warm-blooded animals, including humans. The ubiquitous nature of this bacterium and its spores makes it a frequent problem for the food industry and establishments where large amounts of food are prepared. C. perfringens causes pote...

The aim of this study was to investigate the effect of some food additives used in foods on cold tolerance of Clostridium perfringens at pH close to neutral. Maximal concentrations recommended for foods of sodium benzoate, potassium sorbate, sodium nitrite, monosodium glutamate, or mixtures of those were added to cultures and their effects on C. pe...

Toxigenic fungi invade crops prior to harvest as well as during storage and produce harmful, even carcinogenic toxins such as aflatoxins. Since consumers demand safe commodities, and due to enhanced public awareness of the dangers of many synthetic fungicides, the importance of investigating alternative, natural products to control these toxigenic...

The microaerophilic nature of Campylobacter and its requirement of ∼5% O(2) for growth have complicated its recovery from foods. The addition to the enrichment media of oxygen quenchers such as charcoal or blood could interfere with PCR for its detection. In this study, a two-step simple aerobic method for Campylobacter detection is proposed. A mod...

Aspergillus parasiticus and Aspergillus flavus produce aflatoxins that cause major losses in crop values. Correlations between morphological changes and loss of virulence or secondary metabolite production have been reported for filamentous fungi. Extracts of several species of Agave inhibit fungal growth and aflatoxin production; however, no infor...