Effect of processing on the microbiological quality and safety of chicken carcasses at slaughterhouse

Microbiological contamination of chicken meat depends on the conditions under which the animals are reared, slaughtered and processed. The aim of this study was to determine the influence of farm origin and processing stages at slaughterhouse on the microbial safety and quality of chicken. Samples of chicken carcasses from three different farms were taken from a slaughterhouse. Mesophiles, Escherichia coli, coagulase positive Staphylococcci counts, presence of Listeria monocytogenes,Campylobacter and Salmonella were determined at five sampling points: after defeathering, after evisceration, after washing, after chilling and after cutting. Chilling reduced log numbers of mesophiles, coagulase positive Staphylococci and E. coli by 0.85, 1.52 and 2.2 log units, respectively. Salmonella was not detected after chilling. High prevalence of Campylobacter spp was observed at all the stages ranging between 84% and 100%. L. monocytogenes was not detected in chicken carcasses after defeathering. However, it was detected after evisceration and after washing and chilling. The most critical stage for L. monocytogenes contamination was the portioning operation, the prevalence in breast and legs being 88% and 84%, respectively.     

Nonhydrolyzable Heptose Bis- and Monophosphate Analogues Modulate Pro-inflammatory TIFA-NF-κB Signaling

d -Glycero-d -manno-heptose-1β,7-bisphosphate (HBP) and d -glycero-d -manno-heptose-1β-phosphate (H1P) are bacterial metabolites that were recently shown to stimulate inflammatory responses in host cells through the activation of the TIFA-dependent NF-κB pathway. To better understand structure-based activity in relation to this process, a family of nonhydrolyzable phosphonate analogues of HBP and H1P was synthesized. The inflammation modulation by which these molecules induce the TIFA-NF-κB signal axis was evaluated in vivo at a low-nanomolar concentration (6 nM) and compared to that of the natural metabolites. Our data showed that three phosphonate analogues had similar stimulatory activity to HBP, whereas two phosphonates antagonized HBP-induced TIFA-NF-κB signaling. These results open new horizons for the design of pro-inflammatory and innate immune modulators that could be used as vaccine adjuvant.     

Review: Modified Atmosphere Packaging and its effects on the microbiological quality and safety of produce

Modified Atmosphere Packaging and related technologies are increasingly used to extend shelf-life of fresh produce. This paper reviews the effect of such technology on the spoilage microbiological flora and food-borne pathogens which may be present in produce and also on the organoleptic properties of the product.     

新的免疫细胞传感器CANARY的研究应用进展

免疫细胞传感器的出现推动了病原体检测的发展.该文综述了B淋巴细胞作为传感器敏感元件的构建,B细胞传感器的检测原理及其在病原体检测中的应用研究进展,并展望了免疫细胞传感器的潜在发展前景.     

Habitat structure influences below ground biocontrol services: A comparison between urban gardens and vacant lots

Urban agriculture offers a framework for local self-reliance by provisioning food security, employment opportunities, and other community benefits. However, urban agriculture must rely on the supporting and regulating services of the soil food web. Hence, we quantified belowground biocontrol activity in urban gardens and vacant lots in two post-industrial cities using an in situ insect baiting technique. Due to the differences in habitat structure, we hypothesized that belowground biocontrol services will differ between gardens and vacant lots and the influence of habitat structure would differ with the type of biocontrol organism. Results revealed that biocontrol activity, as assessed by % mortality of baited insects, varied between 51% and 98% with higher activity often recorded in vacant lots than gardens. Major contributions to bait insect mortality were by ants, followed by microbial pathogens and entomopathogenic nematodes, respectively. Ants showed higher (p < 0.0001) % mortality in vacant lots (60% ± 33.4%) than in urban gardens (33.3% ± 22.2%) whereas microbial pathogens exhibited higher (p < 0.0001) mortality in gardens (27.8% ± 15%) than vacant lots (8.3% ± 16.7%). Ants caused higher (p < 0.0001) mortality when larger-mesh size cages were used compared with the smaller-mesh size cages, but mortality by microbial pathogens did not differ with cage type. The high biocontrol activity indicates the resilience of the soil food web in urban ecosystems and the differential effects of habitat structure on biocontrol activity can help guide landscape planning and vegetation management to enhance urban environments and boost local self-reliance.     

Temporal patterns in the occurrence of Salmonella in raw meat and poultry products and their relationship to human illnesses in the United States

The prevalence and level of microbial pathogens on various commodities often exhibit seasonal patterns. As a consequence, the incidence of foodborne illness tends to follow these trends. Of the various product classes, the occurrence of microbial contamination can be high on raw meat and poultry products, with Salmonella potentially occurring in all meat and poultry product classes. Since 1999, the Food Safety and Inspection Service in the United States has collected samples of meat and poultry products and analyzed them for the presence of Salmonella. This study uses a common modeling approach to estimate the seasonal change in the proportion of test-positive samples for seven classes of raw meat and poultry products. The results generally support the hypothesis of a seasonal increase of Salmonella during the summer months. The proportions of test-positive samples decrease rapidly in the late fall for all product classes except chicken and ground turkey, which remain somewhat elevated through late winter. A comparison of the pathogens' seasonal pattern in meat and poultry with human cases reveals that the seasonal increase in human cases precedes the seasonal increase in meat and poultry by between one and three months. These results suggest that while contaminated meat and poultry products may be responsible for a substantial number of human cases, they are not necessarily the primary driver of the seasonal pattern in human salmonellosis.     

Transmission of Bacterial Zoonotic Pathogens between Pets and Humans: The Role of Pet Food

Recent Salmonella outbreaks associated with dry pet food and treats raised the level of concern for these products as vehicle of pathogen exposure for both pets and their owners. The need to characterize the microbiological and risk profiles of this class of products is currently not supported by sufficient specific data. This systematic review summarizes existing data on the main variables needed to support an ingredients-to-consumer quantitative risk model to (1) describe the microbial ecology of bacterial pathogens in the dry pet food production chain, (2) estimate pet exposure to pathogens through dry food consumption, and (3) assess human exposure and illness incidence due to contact with pet food and pets in the household. Risk models populated with the data here summarized will provide a tool to quantitatively address the emerging public health concerns associated with pet food and the effectiveness of mitigation measures. Results of such models can provide a basis for improvements in production processes, risk communication to consumers, and regulatory action.     

Essential oil nanoemulsions: antibacterial activity in contaminated fruit juices

Many human acid tolerant bacterial and fungal pathogens can be transmitted through the consumption of the contaminated fruit juices. We aim to formulate essential oil nanoemulsions (basil, black seed, turmeric, clove & cinnamon), determine their ability to clear contamination by food borne bacterial pathogens from fruit juices. The antibacterial activity of the optimised formulations was tested in the fruit juices against bacterial pathogens causing gastrointestinal tract infections. The minimum bactericidal concentration (MBC) of clove emulsions ranged from 15.6 to 25 μL mL⁻¹. Cinnamon oil emulsion had an MBC ranging between 15 and 31 μL mL⁻¹. At MBC, cinnamon oil emulsions caused a 6log₁₀ decrease in viable counts by 8 h and maintained the sterility of fruit juices for 7 days at ambient temperature. Thus, clove and cinnamon microemulsions can be used as juice additives to control food borne bacterial pathogens and maintain the bacterial sterility of fruit juices.     

A multifaceted approach to harness probiotics as antagonists on plant based foods,for enhanced benefits to be reaped at a global level

Investigations into probiotics have focused on their health benefits thus far, with some of the findings finally reaching the food and pharmaceutical industries, which have used them for commercial purposes. In biocontrol research some microbes, mainly isolated from plants, have shown antagonism towards both enteric and plant pathogens, and some of them represent probiotic species. Fresh fruits and vegetables are regarded as health‐promoting dietary constituents, and if probiotics could be used to control the pathogens on them then they could turn out to be even healthier. The fresh produce industry still depends on agrochemicals and the increase in the demand for high‐priced organically grown produce indicates consumer concerns regarding the use of agrochemicals. If the potential of probiotic organisms to serve as biocontrol agents for fresh produce is exploited, all fresh produce can be made as safe as organically grown produce, and much more wholesome. This review appraises the feasibility of such a move by evaluating how research has progressed in both disciplines (probiotic and biocontrol) and suggests sharing results from research via information technology, efficient collaboration, and the use of novel molecular biological tools to achieve the objective of probiotic antagonists. © 2018 Society of Chemical Industry     

Rapid and standardized methods for detection of foodborne pathogens and mycotoxins on fresh produce

Due to the increase in consumption of fresh produce regarding to the health demand in the last decades, a considerable portion of foodborne outbreaks has been trackbacked to contaminated fresh produce, which have appeared as highly possible vehicles for foodborne outbreaks nowadays. Delays in detection of pathogens and mycotoxins on fresh produce hindered the trace-back investigations in finding the source and revealed the urgent need of rapid and reliable methods. In the frame of this review, we summarized available fast, reliable and standardized methods (conventional, molecular, rapid and recently developed methods) used for detection of the most common foodborne pathogens and mycotoxins which are the most likely causative agents of outbreaks caused by contaminated fresh produce.