Quantification and health risk assessment of ochratoxin A in dried fruit, spices, and coffee.

Ochratoxin A (OTA) is a stable toxin produced by fungal strains of Aspergillus and Penicillium. It is commonly found in a variety of food products, including dried fruit, coffee, and spices, raising concerns about their safety. This study was aimed to quantify OTA levels in different food products using HPLC with fluorescence detection. The pre-treatment process was optimised by employing immunoaffinity columns with Tween 20 to effectively remove interfering substances. An analytical method was developed, validated, and applied for OTA analysis in dried fruit, spices, and coffee samples. The validation procedure included determining detection and quantification limits, linearity, precision, and accuracy, as per the criteria specified by AOAC International. The validated method was successfully applied for OTA analysis in the selected food samples. Furthermore, health risk assessment was conducted based on the average intake and body weight of the Korean population. From the results, concentrations of OTA in the samples were found to be very low and therefore concluded not to pose significant threats to consumer health.

Characterization of Cronobacter sakazakii Strains Originating from Plant-Origin Foods Using Comparative Genomic Analyses and Zebrafish Infectivity Studies.

Cronobacter sakazakii continues to be isolated from ready-to-eat fresh and frozen produce, flours, dairy powders, cereals, nuts, and spices, in addition to the conventional sources of powdered infant formulae (PIF) and PIF production environments. To understand the sequence diversity, phylogenetic relationship, and virulence of C. sakazakii originating from plant-origin foods, comparative molecular and genomic analyses, and zebrafish infection (ZI) studies were applied to 88 strains. Whole genome sequences of the strains were generated for detailed bioinformatic analysis. PCR analysis showed that all strains possessed a pESA3-like virulence plasmid similar to reference C. sakazakii clinical strain BAA-894. Core genome analysis confirmed a shared genomic backbone with other C. sakazakii strains from food, clinical and environmental strains. Emerging nucleotide diversity in these plant-origin strains was highlighted using single nucleotide polymorphic alleles in 2000 core genes. DNA hybridization analyses using a pan-genomic microarray showed that these strains clustered according to sequence types (STs) identified by multi-locus sequence typing (MLST). PHASTER analysis identified 185 intact prophage gene clusters encompassing 22 different prophages, including three intact Cronobacter prophages: ENT47670, ENT39118, and phiES15. AMRFinderPlus analysis identified the CSA family class C ß-lactamase gene in all strains and a plasmid-borne mcr-9.1 gene was identified in three strains. ZI studies showed that some plant-origin C. sakazakii display virulence comparable to clinical strains. Finding virulent plant-origin C. sakazakii possessing significant genomic features of clinically relevant STs suggests that these foods can serve as potential transmission vehicles and supports widening the scope of continued surveillance for this important foodborne pathogen.

Aerobic spore-forming bacteria in powdered infant formula: Enumeration, identification by MALDI-TOF mass spectrometry (MS), presence of toxin genes and rpoB gene typing.

This study aimed to assess the counts and biodiversity characterization of aerobic sporeforming bacteria (ASB) in powdered infant formula (PIF). Fifty-four (n = 54) samples of PIF of three brands were analyzed for mesophilic aerobic bacteria, and ASB counts. ASB isolated from PIF were assessed for their ability to produce spoilage enzymes and hemolytic activity and further identified by MALDI-TOF mass spectrometry. Then, the isolates were subjected to rpoB gene typing and assessment of bceT, entFM, nhe (A, B, C), and hbl (A, B, C) toxin genes. The main species isolated were B. licheniformis (54%), followed by B. cereus (33%) and B. subtilis (5%). The ASB counts ranged from 1 to 4 log CFU/g, and the mean was 2.9 log CFU/g for mesophilic aerobic sporeforming bacteria (MSC) and 2.5 log CFU/g for thermophilic aerobic sporeforming bacteria (TSC). Most PIF samples presented MSC and TSC counts between 2 and 3 log CFU/g. A total of 13%, 50%, and 37% of the samples presented MSC counts from <2 log CFU/g, between 2 and 3 log CFU/g and between 3 and 4 log CFU/g, respectively. Among the ASB isolates, 97% had protease, 84% hydrolyzed starch, 66% had hemolytic activity, and 61% had lecithinase activity. A total of 44 out of 120 isolates harbored at least one toxin gene; 56% for B. cereus, 34% for B licheniformis, and less than 5% for B. subtilis, B pumilus, and L. sphaericus. All B. cereus isolates harbored the nhe gene, 60% entFM, 44% cytK, 32% bceT, and 28% hbl genes. Besides, 17% of B. licheniformis harbored nhe. A small proportion of B. subtilis, B. pumilus, and L. sphaericus carried toxin genes. The rpoB based phylogenetic tree provided high resolution among Bacillus species. The findings of this study provide insights into the phenotypic and genotypic biodiversity of Bacillus present in PIF.

Challenges in Recovering Foodborne Pathogens from Low-Water-Activity Foods.

There are numerous obstacles to the detection of foodborne pathogens in foods that exhibit a low water activity (aw). These obstacles include the presence of antimicrobial compounds, particulates, PCR inhibitors, and fatty matrices. New approaches should be sought to increase the sensitivity of pathogen testing in low-aw foods and to overcome the effects of various inhibitors and antimicrobials. The U.S. Food and Drug Administration and other laboratories are working toward this goal. This review will address these issues while delineating specific inhibitors and antimicrobials that impede testing of low-aw foods. A review of relevant rapid and conventional testing methodologies for Salmonella in low-aw foods will also be discussed.

Corrigendum: Quantifying the Responses of Three Bacillus cereus Strains in Isothermal Conditions and During Spray Drying of Different Carrier Agents.

[This corrects the article on p. 1113 in vol. 9, PMID: 29904375.].

Quantifying the Responses of Three Bacillus cereus Strains in Isothermal Conditions and During Spray Drying of Different Carrier Agents.

Spray drying is a widely used method for producing milk powder. This process is not aimed to cause microbial inactivation, thus sporeforming bacteria may be abundant in the microbiota of milk powder. The first aim of this study was to determine the inactivation kinetics parameters in capillary tubes of three Bacillus cereus strains (436, B63, 540) in three menstrua (whole milk, phosphate buffer, and talc suspension) at 90, 100, and 110°C. D-values for B. cereus in the three menstrua were not significantly different at the highest tested temperature (p > 0.05). Thus, talc was chosen as a carrier agent to allow the recovery of B. cereus from spray dried materials given its low interference on inactivation kinetics. B. cereus spores were also inoculated in whole milk and skim milk following spray drying at 95, 105, and 110°C (outlet temperature). After the spray drying runs, B. cereus spores were counted and the number of decimal reductions (γ) calculated. A correlation between the small diameter of the particles with the survival of spores of three B. cereus strains was found, and B. cereus 436 presented consistently the lowest γ no matter temperature and a carrier agent. The highest γ was found when talc powder was used, which suggest that this carrier agent does not protect B. cereus spores during spray drying. Spray drying of milk can lead to up to 4 γ (strain 540) of B. cereus spores but depending on the strain less than one γ (strain 436) could be observed. This study contributes to the knowledge on the microbiology of low water activity foods by providing novel findings regarding the fate of three B. cereus strains to different spray drying conditions. Acknowledging the variability of inactivation of B. cereus during spray drying is key in the current context of food safety in which the quantification of effects of unit operations must be known for the validation of processes and development of more robust formulations.

Influence of spray drying process on the quality of avocado powder: a functional food with great industrial potential / Influencia del proceso de secado por aspersión en la calidad del polvo de aguacate: un alimento funcional con gran potencial industrial

Background: Colombia is the fifth largest producer of avocado and its agribusiness chain lacks value-added diversified products; therefore, at the governmental level, there has been promotion of internationalization policies aimed at opening up new markets and innovation with improved technology and food consumption patterns. The spray drying is an alternative conservation for avocado, a highly perishable fruit. Objectives: the aim of this study was to optimize the spray drying process for obtaining Hass avocado powder with better physicochemical properties and processing. Methods: an experimental design "Optimal" was used in the response surface methodology based on four factors: (A) maltodextrin (MD) concentration (2.81 to 11.25% w/w), (B) air inlet temperature (140-160°C), (C) outlet air temperature (80-90°C) and (D) atomizer disk speed (20000-26000 rpm). Results: the response variables where statistically significant differences (p < 0.05) were found including: moisture, water activity, solubility, color coordinates (L*, a*, b*) hygroscopicity, wettability, extractable oil and deposit formation versus factors studied. Optimized value factors were: (A) 6.93% (B) 160°C (C) 84°C and (D) 26000 rpm. Conclusions: the experimental process optimization is presented as an effective tool for agribusiness, which improves product quality in terms of the factors that affect it, and in the case of avocado, allows the development of new value-added products, with potential uses in the food industry, pharmaceutical, cosmeceutical, among others.

Antecedentes: Colombia es el quinto productor de aguacate y su cadena de agronegocios no cuenta con suficientes productos diversificados de valor agregado; por lo tanto, a nivel gubernamental, se han promovido políticas de internacionalización dirigidas a abrir nuevos mercados e innovación con tecnología mejorada y con patrones en el consumo de alimentos. El secado por aspersión es una alternativa de conservación del aguacate, una fruta altamente perecedera. Objetivos: el objetivo de este estudio fue optimizar el proceso de secado por atomización para obtener polvo de aguacate Hass con mejores propiedades fisicoquímicas y de procesamiento. Métodos: se utilizó un diseño experimental "optimización" en la metodología de superficie de respuesta basado en cuatro factores: (A) concentración de maltodextrina (MD) (2,81 a 11,25% p/p), (B) temperatura del aire de entrada (140-160°C), (C) temperatura del aire de salida (80-90°C) y (D) velocidad del disco del atomizador (20000-26000 rpm). Resultados: las variables de respuesta donde se encontraron diferencias estadísticamente significativas (p<0,05) incluyen: humedad, actividad del agua, solubilidad, coordenadas de color (L*, a*, b*), higroscopicidad, humectabilidad, extracción de aceite y formación de depósitos frente a los factores estudiados. Los factores de valor optimizados fueron: (A) 6.93% (B) 160°C (C) 84°C y (D) 26000 rpm. Conclusiones: la optimización del proceso experimental se presenta como una herramienta efectiva para los agronegocios, que mejora la calidad del producto en términos de los factores que lo afectan, y en el caso del aguacate, permite el desarrollo de nuevos productos de valor agregado, con posibles usos en la industria alimentaria, farmacéutica, cosmecéutica, entre otras.

Direct detection of toxigenic Bacillus cereus in dietary complement for children and cassava starch / Detección directa de Bacillus cereus toxigénicos en complementos dietarios para niños y en almidón de yuca / Detecção direta de Bacillus cereus toxigênicos em suplementos alimentares para crianças e amido de mandioca

Bacillus cereus is a food contaminant and a known human pathogen that can cause emetic and diarrheal syndromes. In this study we evaluated the presence of toxigenic B. cereus by multiplex PCR directly in dietary complement for children and cassava starch samples collected on Medellin, Colombia. Of 75 dietary complement for children samples evaluated, 70.7% were contaminated with toxigenic B. cereus and four different toxigenic consortia were detected: I: nheA, hblC, cytK (9.8%), II: nheA, hblC (2%), III: hblC, cytK (41.2%), IV: hblC (47%). Of 75 cassava starch samples, 44% were contaminated with toxigenic B. cereus and four different toxigenic consortia were determined: I: nheA, hblC, cytK (48.5%), II: nheA, hblC, cytK, cesB (3%), III: hblC, cytK (30.3%), IV: hblC (18.2%). In general, in dietary complement for children only enterotoxigenic consortia were detected while in cassava starch the enterotoxigenic consortia predominated over the emetic. Multiplex PCR was useful to detect toxigenic B. cereus contamination allowing direct and simultaneous detection of all toxin genes in foods. This study is the first in Colombia to evaluate toxigenic B. cereus, providing information of importance for microbiological risk evaluation in dried foods.

Bacillus cereus es un contaminante de alimentos conocido por ser patogénico para los humanos, causando síndromes de vómito y diarrea. En este estudio se evaluó la presencia de B. cereus toxigénicos utilizando PCR múltiple directamente en complementos dietarios para niños y en almidón de yuca colectados en Medellín, Colombia. De 75 muestras de complemento dietario para niños, 70,7% estuvieron contaminadas con B. cereus toxigénicos y se detectaron cuatro diferentes consorcios toxigénicos: I: nheA, hblC, cytK (9,8%), II: nheA, hblC (2%), III: hblC, cytK (41.2%), IV: hblC (47%). De 75 muestras de almidón de yuca, 44% estuvieron contaminadas con B. cereus toxigénicos y se determinaron cuatro diferentes consorcios toxigénicos: I: nheA, hblC, cytK (48.5%), II: nheA, hblC, cytK, cesB (3%), III: hblC, cytK (30,3%), IV: hblC (18.2%). En general, en los complementos dietarios para niños sólo se detectaron consorcios enterotoxigénicos, mientras que en el almidón los consorcios enterotoxigénicos predominaron sobre el emético. La PCR múltiple fue de utilidad para detectar contaminación con B. cereus toxigénicos permitiendo la detección directa y simultánea de todos los genes tóxicos en los alimentos. Este estudio es el primero en Colombia en evaluar B. cereus toxigénicos y proporciona información importante para la evaluación de riesgos microbiológicos en los alimentos pulverizados.

Bacillus cereus é um contaminante de alimentos e é conhecido por ser patogénico nos seres humanos ocasionando síndromes de vômitos e diarreia. Neste estudo foi avaliada a presença de B. cereus toxigênicos por PCR multiplex diretamente em complementos da dieta para crianças e amido de mandioca, em amostras coletadas em Medellín, na Colômbia. De 75 amostras dos complementos da dieta para crianças, 70,7% estiveram contaminadas com B. cereus toxigênicos e foram detectados quatro diferentes consórcios: I: nheA, hblC, cytK (9,8%), II: nheA, hblC (2%), III: hblC, cytK (41,2%), IV: hblC (47%). De 75 amostras de amido de mandioca, 44% estiveram contaminadas com B. cereus toxigênicos e quatro consórcios diferentes foram determinados: I: nheA, hblC, cytK (48,5%), II: nheA, hblC, cytK, cesB (3%) III: hblC, cytK (30,3%), IV: hblC (18,2%). Em geral, nos complementos da dieta para crianças foram detectados apenas consórcios enterotoxigênicos, não obstante no amido os consórcios enterotoxigênicos predominaram sobre o emético. A PCR multiplex foi útil para detectar contaminação com B. cereus toxigênico permitindo a detecção direta e simultânea de todos os genes tóxicos em alimentos. Este estudo é o primeiro na Colômbia em avaliar B. cereus toxigênico e providencia informação importante para a avaliação de riscos microbiológicos em alimentos pulverizados.