The deadliest foodborne pathogen in terms of fatality rates is often considered to be *Listeria monocytogenes*. While infections from Listeria are less common compared to other pathogens like Salmonella or E. coli, the consequences can be much more severe, especially for certain high-risk populations. Read more at the link above.
Posted in Food Microbiology Research, Listeria, Listeria Deli Meats, Listeria Enoki Mushrooms, Listeria France, Listeria Ice Cream, Listeria in Cheese, Listeria innocua, Listeria invanovi, Listeria monocytogenes, Listeria Smoked Fish, Listeria valentina, Listeria welshimeri, Listeriolysin, listeriosis, Pet Food Listeria monocytogenes, Research
Validated alternative test methodologies may be used in place of culture-based methods recommended for environmental monitoring programs (EMPs) for Listeria in food production facilities. In order to help guide decisions on which testing method to use to simplify Listeria EMP implementation in food production facilities, alternative methods were compared to the culture-based method in actual EMPs for Listeria. Seventy-two samples collected from two facilities of souzai production businesses that use meat and meat products as ingredients, one facility of processed meat product production business, and one facility of processed meat product and souzai production business were applied to EMPs for Listeria using the culture-based method, 3MTM Molecular Detection System (MDS), and InSite L. mono Glo (InSite). The kappa coefficient in MDS was 0.65 for Listeria monocytogenes and 0.74 for Listeria spp., both of which were deemed substantial compared with the culture-based method. The kappa coefficient in InSite was −0.01 for L. monocytogenes and 0.50 for Listeria spp., which indicated poor and moderate reproducibility, respectively. When the medium of InSite was smeared on agar medium, 7 of the 19 samples tested positive only for Listeria spp. (negative for L. monocytogenes) but L. monocytogenes was cultured, indicating that the sensitivity of detecting L. monocytogenes via fluorescence may be low. MDS was considered a useful alternative for both L. monocytogenes and Listeria spp. as targets, and InSite was not possible as a substitute for detecting L. monocytogenes; however, it is considered a helpful alternative method for detecting Listeria spp. EMPs for Listeria often target Listeria spp. as an indicator of L. monocytogenes. The alternative methods studied in this study are rapid, simple, and useful in EMPs for Listeria. However, the data in this study were a comparatively small sample set and impacted by variability, so more robust comparisons are desirable in the future.
Listeria bacteria are widespread in the environment and they are worldwide commonly found in soil and water, as well as in animal digestive tracts. There are more than 15 species of bacteria in this genus, but human cases of Listeria infection are almost always caused by Listeria monocytogenes (L. monocytogenes) while Listeria ivanovii is pathogenic in animals but rarely in humans. The other species are not considered to be pathogenic in humans or animals.
L. monocytogenes are able to form communities of bacteria called biofilms and are therefore resistant to a wide range of stresses. This capacity varies among genotypes . They can tolerate acidic, dry and salty conditions, in the presence or absence of oxygen. Moreover, unlike most pathogenic bacteria, they are able to survive and multiply in refrigerated foods, making ready-to-eat foods of particular concern.
Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Listeria, Listeria invanovi, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pathogen, pathogenic, Research
The use of active coatings is shown as an option to offer safe ready-to-eat fruits and respond the growing demand of consumers for fresh, environmentally friendly and products free from chemical preservatives. In this work, chitosan (Ch), chitosan + vanillin (Ch-V), and chitosan + geraniol (Ch-G) coatings were applied on apple cubes to evaluate their microbiological quality for 12 days of refrigerated storage. All combinations applied demonstrated significant bactericidal effects on native microbiota, resulting in number of mesophilics, psychrotrophics, and yeasts and molds under the detection limit (<2.00 log) immediately after coating and during 12 days for most of them. Moreover, Escherichia coli O157:H7 and Listeria innocua artificially inoculated on apple cubes showed great reductions after coating treatments, exerting vanillin or geraniol enriched coatings outstanding antimicrobial activity. In fact, after 12 days of refrigerated storage, apple cubes treated with vanillin and geraniol (>2.00 log CFU/g) showed reductions in E. coli O157:H7 counts greater than 2.00 log in comparison with the control (4.68 log CFU/g). The preliminary results of this study demonstrated that Ch, Ch-Va, and Ch-Ge could be an interesting alternative to improve the safety of apple cubes and, therefore, a novel option to offer safe, ready-to-eat apple to consumers.
Posted in Decontamination Microbial, E.coli O157, E.coli O157:H7, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria invanovi, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research
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In recent years, the role of Listeria monocytogenes as a foodborne pathogen in public health has increased. Its presence poses a risk for humans, especially in ready-to-eat foods, such as ham. Understanding the presence and distribution of Listeria spp. on swine carcasses meant for Italian dry-cured hams can be a useful tool to improve food safety. This study assessed the distribution of Listeria spp. (as a marker of contamination with L. monocytogenes) on slaughtered pig carcasses intended for the production of high-quality, Italian, dry-cured ham and examined the roles of the site sampled on the carcass, farming cycle (open versus closed), farm-to-slaughterhouse distance, and time spent in lairage. Samples were collected from swine carcasses (n = 150) before refrigeration, from three different carcass locations (head, shoulder, and thigh), and assessed for the presence of listeriae. A total of 115 carcasses were contaminated with Listeria spp. in at least one location. In all, 178 listeriae were isolated and identified: 130 Listeria innocua, 28 Listeria welshimeri, 17 Listeria ivanovii, and 3 L. monocytogenes. Listeriae were detected on 62.7% of heads, on 25.3% of shoulders, and on 30.7% of thighs, with significant differences between heads versus shoulders and thighs. Animals reared in closed-cycle farms were more contaminated (P < 0.05) than were animals from open-cycle farms (90 versus 71.8%). The distance between farms and slaughterhouse was not related to the contamination rate. Carcasses of swine that stayed in lairage before slaughtering for more than 10 h showed a higher degree of contamination (90%) and were positive for Listeria spp. in more sample sites (55%) compared with those held for less than 2 h (73% of carcasses and 33.3% of samples). Our results show that heads should be detached from carcasses immediately after slaughter for meat-safety purposes and the amount of time animals stay in lairage should be limited. These results will be useful for a more-valid implementation of good manufacturing processes for slaughtering.
FoodWorld 