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This study aimed to determine the prevalence of Listeria spp. in fresh shrimp in Bogor, Indonesia, and to determine the antibiotic susceptibility patterns of isolated Listeria spp. A quantitative descriptive approach was employed. A total of 25 samples of fresh shrimp were obtained from randomly selected traditional markets (n = 18) and modern markets (n = 7). The results revealed that 14 samples (56.0%) were positive for Listeria spp. Among them, 11 (78.6%) and 3 (21.4%) were selected from traditional markets and modern markets, respectively. Thirty-six isolates, which upon biochemical characterization included 1 (2.8%) Listeria innocua, 26 (72.2%) Listeria grayi, 1 (2.8%) Listeria welshimeri, and 8 (22.2%) Listeria-like strains, were identified. The most common isolates were L. grayi, while the least common were L. innocua and L. welshimeri. The disk diffusion assay determined the susceptibility of the 36 strains to 10 commercial antibiotics. In general, 100% of the 36 isolated Listeria spp. were resistant to amoxicillin and nebacetin, and almost 100% were susceptible to chloramphenicol. However, antibiotic multiple resistance (AMR) was observed, with all Listeria strains resistant to more than two antibiotics. No isolate was resistant to only one antibiotic. The present study provides the first baseline data on the prevalence of Listeria spp. in fresh shrimp in Indonesia and the susceptibility of these isolates to antibiotics. [ABSTRACT FROM AUTHOR]

Camel milk is a valuable food choice, representing a primary need in the diet of people in dry zones. Camel milk is rich in nutrients, which makes it a favorable environment for the development of microorganisms. Staphylococcus and Listeria are significant opportunistic pathogens in humans, dairy cattle, and camels. The presence of these bacteria could present a potential public health issue. In the present study, 20 milk samples collected from camel farms in M'sila were investigated for the presence of Staphylococcus spp. and Listeria spp. Staphylococcus enumeration, and a search for Listeria spp. was performed according to the recommendations of ISO 6888-1(2004) and ISO 11290-1(2017) methods, respectively. The results show a contamination prevalence of 62% of staphylococcus spp. with an estimated average bacterial load of 2.7.102 cfu/mL, while for Listeria spp., only three samples were positive, with a prevalence of 14.28%. For each species, identification using API Listeria strips confirmed the presence of Listeria grayi, Listeria innocua, and Listeria seeligeri species, but no Listeria monocytogenes were recovered in these samples. According to the current results, we could conclude that the percentage of contamination with Staphylococcus in the tested camel milk samples was relatively high compared to the level of contamination with Listeria. There is no Algerian regulation setting microbiological criteria for raw camel milk; however, these results suggest that the hazard to the consumer cannot be excluded. [ABSTRACT FROM AUTHOR]

This survey aimed to study the occurrence of Listeria species in fish and meat samples and characterization of their virulence genes. Over all, Listeria spp. was found in 25.22% samples out of which 9.0% and 16.21% were L. monocytogenes and L. innocua,respectively. L. monocytogenes (n=10) belonged to 4b, 4d and 4e serovars. All the isolates revealed presence of virulence genes- plcA and iap, while plcB gene was also present in 90% of the isolates. The occurrence of L. monocytogenes in samples shows cogent evidence for their zoonotic potential and has public health significance.

Camel milk is a valuable food choice, representing a primary need in the diet of people in dry zones. Camel milk is rich in nutrients, which makes it a favorable environment for the development of microorganisms. Staphylococcus and Listeria are significant opportunistic pathogens in humans, dairy cattle, and camels. The presence of these bacteria could present a potential public health issue. In the present study, 20 milk samples collected from camel farms in M’sila were investigated for the presence of Staphylococcus spp. and Listeria spp. Staphylococcus enumeration, and a search for Listeria spp. was performed according to the recommendations of ISO 6888-1(2004) and ISO 11290-1(2017) methods, respectively. The results show a contamination prevalence of 62% of staphylococcus spp. with an estimated average bacterial load of 2.7.102 cfu/mL, while for Listeria spp., only three samples were positive, with a prevalence of 14.28%. For each species, identification using API Listeria strips confirmed the presence of Listeria grayi, Listeria innocua, and Listeria seeligeri species, but no Listeria monocytogenes were recovered in these samples. According to the current results, we could conclude that the percentage of contamination with Staphylococcus in the tested camel milk samples was relatively high compared to the level of contamination with Listeria. There is no Algerian regulation setting microbiological criteria for raw camel milk; however, these results suggest that the hazard to the consumer cannot be excluded.

Most Austrian dairies and cheese manufacturers participated in a Listeria monitoring program, which was established after the first reports of dairy product-associated listeriosis outbreaks more than thirty years ago. Within the Listeria monitoring program, up to 800 mL of product-associated liquids such as cheese smear or brine are processed in a semi-quantitative approach to increase epidemiological sensitivity. A sampling strategy within cheese production, which detects environmental contamination before it results in problematic food contamination, has benefits for food safety management. The liquid-based sampling strategy was implemented by both industrial cheese makers and small-scale dairies located in the mountainous region of Western Austria. This report considers more than 12,000 Listeria spp. examinations of liquid-based samples in the 2009 to 2018 timeframe. Overall, the occurrence of L. monocytogenes in smear liquid samples was 1.29% and 1.55% (n = 5043 and n = 7194 tested samples) for small and industrial cheese enterprises, respectively. The liquid-based sampling strategy for Listeria monitoring at the plant level appears to be superior to solid surface monitoring. Cheese smear liquids seem to have good utility as an index of the contamination of cheese up to that point in production. A modelling or validation process should be performed for the new semi-quantitative approach to estimate the true impact of the method in terms of reducing Listeria contamination at the cheese plant level.

Listeria spp. are ubiquitous in nature and can be found in various environmental niches such as soil, sewage, river water, plants, and foods, but the most frequently isolated species are Listeria monocytogenes and Listeria innocua. In this study, the presence of Listeria spp. in raw chicken meat and chicken-related products sold in local markets in Klang Valley, Malaysia was investigated. A total of 44 Listeria strains (42 L. innocua and 2 L. welshimeri) were isolated from 106 samples. Antibiotic susceptibility tests of the L. innocua strains revealed a high prevalence of resistance to clindamycin (92.9%), ceftriaxone (76.2%), ampicillin (73.8%), tetracycline (69%), and penicillin G (66.7%). Overall, 31 L. innocua and 1 L. welshimeri strain were multidrug resistant, i.e., nonsusceptible to at least one antimicrobial agent in three or more antibiotic classes. The majority of the L. innocua strains were placed into five AscI pulsogroups, and overall 26 distinct AscI pulsotypes were identified. The detection of multidrug-resistant Listeria strains from different food sources and locations warrants attention because these strains could serve as reservoirs for antimicrobial resistance genes and may facilitate the spread and emergence of other drug-resistant strains. [ABSTRACT FROM AUTHOR]

Recently, the European Food Safety Authority proposed that each EU member state should conduct a survey of Listeria monocytogenes in soft cheeses for sale in retail outlets. Hence, retail samples of soft cheeses in Greece ( n = 137) were analyzed qualitatively and quantitatively for both L. monocytogenes and other Listeria spp., as well as for pH and a. None of the cheeses analyzed were found positive for L. monocytogenes (0%; 95% confidence interval (CI) = 0.0-2.2%). Three samples (2.2%; 95% CI = 0.5-6.3%) were positive for other Listeria spp., with populations ranging from <5 to 4.5 × 10 CFU g. Although soft cheeses are regarded as foods that permit the proliferation of L. monocytogenes, 15.4% of the whey cheeses tested had pH values ≤4.4 and 29% of the interior mold-ripened cheeses had a values ≤0.92. Such low pH values for whey cheeses are unexpected, based on their manufacturing technology, and are associated with lower quality and reduced shelf life. Nonetheless, in the present survey, the percentage of whey cheeses in the Greek retail market exhibiting unusually low pH values or testing positive for Listeria spp. was much lower compared to the respective percentages reported from studies conducted in the 1990s. The absence of L. monocytogenes in the tested cheeses undoubtedly constitutes an encouraging result with respect to the safety of soft cheeses in the Greek retail market. However, the presence of other Listeria spp. in three of the tested samples implies that L. monocytogenes would, most likely, also be present in the food-processing or retail-handling environments of these products. Therefore, cheese manufacturers and retail handlers should continue or even intensify the application of all necessary measures with the aim of preventing food contamination. [ABSTRACT FROM AUTHOR]

This cross-sectional study determined the prevalence of Listeria spp. in bulk-tank milk on dairy farms in the region of Galicia in northwest Spain. The aim was to identify management practices associated with the presence ofListeria spp. and possible effects on milk hygienic quality. A total of 98 farms was randomly selected on the basis of an expected prevalence of 6.5% for Listeria monocytogenes from 20,107 dairy farms in the region. Bulk-tank milk samples were obtained from 98 farms, fecal samples from lactating cows from 97 farms, and silage samples from 83 farms. Listeria monocytogenes was detected in 6.1, 9.3, and 6.0% of these samples, respectively. Statistical analyses confirmed the relationship between low silage quality (as indicated by high pH) and presence ofListeria spp. in silage (29.5 vs. 6.2% for pH above or below 4.5, respectively). Only milking system [tie-stall systems (28.6%) vs. parlor milking (10%)] and inadequately controlled milking order [yes (32.0%) vs. no (10.7%)] had statistically significant effects on management practices for increasing the risk of Listeria contamination of bulk-tank milk. [ABSTRACT FROM AUTHOR]

Bison meat is a relatively new, emerging meat species gaining increased popularity in the US and European meat markets, but little is known of its microflora or pathogens that may be present. This study was carried out to determine the incidence of the foodborne pathogens Listeria, Salmonella, Escherichia coli/E. coli O157:H7 on slaughtered bison and to evaluate the bison slaughter process. Bison carcass sampling was carried out at monthly intervals over a period of 1 year at a Bison processing facility in the Midwestern United States. A total of 355 Bison carcasses were sampled by surface swabbing the carcasses at five points on the production line: pre-dehiding, post-evisceration, post-USDA inspection, post-washing and 24 h chilled carcass. Overall, the prevalence of Listeria spp., Salmonella spp., E. coli and E. coli O157:H7 was 18.3%, 3.94%, 38.3% and 1.13%, respectively. The prevalence of Listeria spp. at each sampling point tested was 42.24%, 18.1%, 6.03%, 1.72% and 3.77% while the prevalence of E. coli at each sampling point was: 88.79%, 73.28%, 52.59%, 56.89% and 11.3%, respectively. The data obtained suggests that current antimicrobial intervention strategies used at the plant are relatively effective in reducing Listeria and E. coli contamination on bison carcasses to some extent, however further study is required to determine the influence of current slaughter practices on carcass contamination. The data reported in this study to the authors’ knowledge is some of the first information reporting on the bacteriological status of Bison, and provides some useful baseline information for future research. [Copyright &y& Elsevier]

Most Austrian dairies and cheese manufacturers participated in a Listeria monitoring program, which was established after the first reports of dairy product-associated listeriosis outbreaks more than thirty years ago. Within the Listeria monitoring program, up to 800 mL of product-associated liquids such as cheese smear or brine are processed in a semi-quantitative approach to increase epidemiological sensitivity. A sampling strategy within cheese production, which detects environmental contamination before it results in problematic food contamination, has benefits for food safety management. The liquid-based sampling strategy was implemented by both industrial cheese makers and small-scale dairies located in the mountainous region of Western Austria. This report considers more than 12,000 Listeria spp. examinations of liquid-based samples in the 2009 to 2018 timeframe. Overall, the occurrence of L. monocytogenes in smear liquid samples was 1.29% and 1.55% (n = 5043 and n = 7194 tested samples) for small and industrial cheese enterprises, respectively. The liquid-based sampling strategy for Listeria monitoring at the plant level appears to be superior to solid surface monitoring. Cheese smear liquids seem to have good utility as an index of the contamination of cheese up to that point in production. A modelling or validation process should be performed for the new semi-quantitative approach to estimate the true impact of the method in terms of reducing Listeria contamination at the cheese plant level. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to establish the occurrence of Listeria spp., especially Listeria monocytogenes in ready to eat RTE food marketed in Algiers (Algeria). A total of 227 samples were collected from different producers and retailers. All samples were analyzed using a conventional cultivation method AFNOR V08-055. Out of 227 samples tested, 21 (9.3%) tested positive for Listeria spp. among them, 6 (2.6%) tested positive for L. monocytogenes. L. innocua was the most common Listeria species found being detected in 11 samples (4.8%), although both Listeria ivanovii and Listeria welshimeri were detected in 3 (1.3%) and 1 (0.4%) food samples respectively. The study of the antimicrobial sensitivity of Listeria monocytogenes strains showed no resistance. The study has enabled us to detect these contaminants in a wide range of RTE foods, to suggest that contamination likely occurs after heat treatment, and to assess the danger represented by this category of food for populations at risk. [Copyright &y& Elsevier]