Lactic acid bacteria viability in different refrigerated food matrices: a systematic review and Meta­analysis.

The aim of this systematic review and meta-analysis was to determine which variables affect the viability of lactic acid bacteria (LAB) added to different types of refrigerated foods during the first 28 days. Scopus, ScienceDirect, PubMed and Cochrane Central Register of Reviews databases were searched from 1997 to April 2022. A total of 278 studies, which showed randomized and controlled experiments published in peer reviewed journals, were included. The viability of LAB in different moments during the storage process was synthesized as mean point estimate (MPE) via random-effects meta-analyses and the effect of multiple factors on the LAB´s viability was evaluated by multiple meta-regression. The meta-analysis showed that the decrease in LAB viability will be more abrupt the greater the initial dose. The physical structure of food may influence bacterial viability. Fruit was the type of product that most quickly lost viability. Co-culture of two or more species did not affect viability. Preservation methods had an unfavorable effect and prebiotics had a beneficial effect on bacterial viability. Viability was genus dependent. The data obtained in this study provide an overview of the factors to be taken into account for the design of new foods.

Prevalence, genotypic diversity and detection of virulence genes in thermotolerant Campylobacter at different stages of the poultry meat supply chain.

Thermotolerant Campylobacter is the leading bacterial cause of foodborne illness in humans worldwide. The objectives of this study were to estimate prevalence and to identify and characterize potential sources of thermotolerant Campylobacter contamination in broilers on farms and at the slaughterhouse; to evaluate the clonal relationship among thermotolerant Campylobacter isolates from different stages of the broiler meat supply chain, and to analyze the presence of virulence genes in different sources of thermotolerant Campylobacter. A total of 1210 samples were collected from three broiler meat supply chains in Santa Fe, Argentina. At the farms, the sampling collection included broilers one week prior to slaughter, wild-living birds, domestic dogs, wild rodents, farm workers' boots, litter, feed, drinking water, flies, and darkling beetles (Alphitobius diaperinus). At the slaughtering line, the samples taken were from the evisceration zone (broiler cecum, working surfaces, evisceration knives and workers' hands), from the chiller zone (surfaces and direct supply water) and from the packing zone (work surfaces, workers' hands and broiler carcasses). The samples taken along each supply chain were in the same batch. The isolates obtained were identified to the species level (C. jejuni and C. coli) by multiplex PCR and were analyzed using pulsed-field gel electrophoresis to compare different profiles according to the source. Finally, the presence of 11 virulence genes was examined (cadF, cdtA, cdtB, cdtC, ciaB, flaA, flhA, iam, wlaN, virB11, racR). From 254 isolates, 128 (50.4%) were Campylobacter jejuni and 126 (49.6%) Campylobacter coli. C. jejuni was the species most prevalent in farm and C. coli the species most prevalent at the slaughterhouse. We detected thermotolerant Campylobacter in samples of wild birds, darkling beetles, farm workers' boots, flies and litter. At the slaughterhouse, the prevalence varied along the process line. By analyzing PFGE results, C. jejuni showed 21 profiles with three predominant genotypes, while C. coli showed 14 profiles with four predominant genotypes. A high genotype diversity was found; however, relationships between isolates from different stages of the broiler meat chain, between broiler and potential sources of thermotolerant Campylobacter contamination and between strains in the farm and in the slaughterhouse were detected. Furthermore, there was evidence of cross-contamination at the slaughterhouse. FlaA, flhA genes were detected in all strains, and the third most prevalent virulence gene was cadF. Only those strains obtained from flies, wild-living birds and broiler carcass samples harbored 10 of 11 pathogenic genes. The prevalence of some pathogenic genes between C. jejuni and C. coli was different. This evidence should contribute the scientific basis to implement risk management measures in public health.

[Epidemiological study of recorded trichinosis cases in Santa Fe Province, Argentina, 1998-2009]. / Estudio epidemiológico de los casos de triquinelosis registrados en la provincia de Santa Fe, Argentina, 1998-2009.

OBJECTIVE: To characterize recorded trichinosis cases and outbreaks in Santa Fe Province, Argentina, from 1998 to 2009 from epidemiological, clinical, and laboratory viewpoints. METHODS: An analysis was conducted of 1 519 epidemiological records of persons who had signs and symptoms compatible with trichinosis in Santa Fe Province in the period 1998-2009. A descriptive statistical analysis of information in epidemiological records and of clinical and laboratory results, as well as a bifactorial analysis of possible associations with epidemiological and environmental factors were also carried out. RESULTS: Trichinosis symptoms were found in 1 276 cases; 372 met the clinical case definition and 224 samples were positive by indirect immunofluorescence, independent of their clinical case classification. There were 27 outbreaks that involved 1 157 cases identified in eight departments, with greater frequency in the province's center and south. Annual distribution of epidemiologically associated cases was heterogeneous, with greater frequency in the period 2000-2003 and in the months of August to October. Probability of becoming sick was greater with consumption of products from informal sources (OR = 3.69; P = 0.014) and in rural areas (OR = 1.799; P = 0.011). Disease incubation period (median) was 12 days. The risk of becoming sick was 2.06 times greater in persons who ate meat or ate pork by-products than in those who did not. CONCLUSIONS: The greatest number of outbreaks occurred in departments that were more populous and where pork production was greater. Specific actions should be designed for prevention and control of the disease in those departments. Epidemiological risk analysis should be considered in evaluating, managing, and communicating trichinosis health risks.

Estudio epidemiológico de los casos de triquinelosis registrados en la provincia de Santa Fe, Argentina, 1998-2009 / Epidemiological study of recorded trichinosis cases in Santa Fe Province, Argentina, 1998-2009

OBJETIVO: Caracterizar desde los puntos de vista epidemiológico, clínico y de laboratorio los casos y brotes de triquinelosis que se registraron en la provincia de Santa Fe, Argentina, entre 1998 y 2009. MÉTODOS: Se analizaron 1 519 fichas epidemiológicas de personas que presentaron síntomas y signos compatibles con triquinelosis en la provincia de Santa Fe en el período 1998-2009. Se realizó el análisis estadístico descriptivo de la información contenida en las fichas epidemiológicas y los resultados clínicos y de laboratorio; se aplicó el análisis bifactorial para determinar las posibles asociaciones con factores epidemiológicos y ambientales. RESULTADOS: Se encontraron síntomas de triquinelosis en 1 276 casos; 372 cumplían la definición de caso clínico y 224 muestras resultaron positivas por inmunofluorescencia indirecta, independientemente de su clasificación como caso clínico. Se identificaron 27 brotes que involucraron a 1 157 casos en ocho departamentos, con mayor frecuencia en el centro y el sur de la provincia. La distribución anual de los casos asociados epidemiológicamente entre sí fue heterogénea, con una mayor frecuencia en el período 2000-2003 y en los meses de agosto a octubre. Hubo mayor probabilidad de enfermar cuando se consumieron productos de fuentes informales (OR = 3,69; P = 0,014) y en las áreas rurales (OR = 1,799; P = 0,011). El período de incubación de la enfermedad (mediana) fue de 12 días. Las personas que consumieron carne de cerdo o sus derivados tuvieron 2,06 veces más riesgo de enfermar que las que no la consumieron. CONCLUSIONES: El mayor número de brotes ocurrió en los departamentos más poblados y con mayor producción porcina. Se deben diseñar acciones específicas de prevención y control de la enfermedad en esos departamentos. Se debe considerar el análisis epidemiológico de riesgos al evaluar, gestionar y comunicar los riesgos sanitarios de triquinelosis.

OBJECTIVE: To characterize recorded trichinosis cases and outbreaks in Santa Fe Province, Argentina, from 1998 to 2009 from epidemiological, clinical, and laboratory viewpoints. METHODS: An analysis was conducted of 1 519 epidemiological records of persons who had signs and symptoms compatible with trichinosis in Santa Fe Province in the period 1998-2009. A descriptive statistical analysis of information in epidemiological records and of clinical and laboratory results, as well as a bifactorial analysis of possible associations with epidemiological and environmental factors were also carried out. RESULTS: Trichinosis symptoms were found in 1 276 cases; 372 met the clinical case definition and 224 samples were positive by indirect immunofluorescence, independent of their clinical case classification. There were 27 outbreaks that involved 1 157 cases identified in eight departments, with greater frequency in the province's center and south. Annual distribution of epidemiologically associated cases was heterogeneous, with greater frequency in the period 2000-2003 and in the months of August to October. Probability of becoming sick was greater with consumption of products from informal sources (OR = 3.69; P = 0.014) and in rural areas (OR = 1.799; P = 0.011). Disease incubation period (median) was 12 days. The risk of becoming sick was 2.06 times greater in persons who ate meat or ate pork by-products than in those who did not. CONCLUSIONS: The greatest number of outbreaks occurred in departments that were more populous and where pork production was greater. Specific actions should be designed for prevention and control of the disease in those departments. Epidemiological risk analysis should be considered in evaluating, managing, and communicating trichinosis health risks.

Pathogen translocation and histopathological lesions in an experimental model of Salmonella Dublin infection in calves receiving lactic acid bacteria and lactose supplements.

The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 10(9) CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 × 10(10) CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection.

Molecular microbial analysis of lactobacillus strains isolated from the gut of calves for potential probiotic use.

The intestinal microbiota has an influence on the growth and health status of the hosts. This is of particular interest in animals reared using intensive farming practices. Hence, it is necessary to know more about complexity of the beneficial intestinal microbiota. The use of molecular methods has revolutionized microbial identification by improving its quality and effectiveness. The specific aim of the study was to analyze predominant species of Lactobacillus in intestinal microbial ecosystem of young calves. Forty-two lactic acid bacteria (LAB) isolated from intestinal tract of young calves were characterized by: Amplified Ribosomal DNA Restriction Analysis (ARDRA), by using Hae III, Msp I, and Hinf I restriction enzymes, and 16S rDNA gene sequencing. ARDRA screening revealed nine unique patterns among 42 isolates, with the same pattern for 29 of the isolates. Gene fragments of 16S rDNA of 19 strains representing different patterns were sequenced to confirm the identification of these species. These results confirmed that ARDRA is a good tool for identification and discrimination of bacterial species isolated from complex ecosystem and between closely related groups. This paper provides information about the LAB species predominant in intestinal tract of young calves that could provide beneficial effects when administered as probiotic.