Prevalence Of Listeria Species Research Articles

A comparative study on the occurrence, genetic characteristics, and factors associated with the distribution of Listeria species on cattle farms and beef abattoirs in Gauteng Province, South Africa

These cross-sectional studies reported the occurrence, genetic characteristics, and factors associated with the distribution of Listeria species on cattle farms and beef abattoirs in Gauteng Province, South Africa. A total of 328 samples (faeces, feeds, silage, and drinking water) were collected from 23 cattle farms (communal, cow-calf, and feedlot), and 262 samples (faeces, carcass swabs, and effluents) from 8 beef abattoirs (low throughput and high throughput) were processed using standard bacteriological and molecular methods to detect Listeria species. The factors associated with the prevalence of Listeria species were investigated, and multiplex polymerase chain reaction (mPCR) was used to determine Listeria species, the pathogenic serogroups, and the carriage of eight virulence-associated genes by Listeria monocytogenes. The overall prevalence of Listeria species in cattle farms was 14.6%, comprising Listeria innocua (11.3%), Listeria monocytogenes (3.4%), Listeria welshimeri (0.0%) compared with 11.1%, comprising Listeria innocua (5.7%), Listeria monocytogenes (4.6%), Listeria welshimeri (0.8%) for beef abattoirs. Of the three variables (area, type of farm/abattoir, and sample type) investigated, only the sample types at abattoirs had a significant (P < 0.001) effect on the prevalence of L. innocua and L. welshimeri. The frequency of distribution of the serogroups based on 11 L. monocytogenes isolated from farms was 72.7% and 27.3% for the serogroup 1/2a-3a and 4b-4d-4e, respectively, while for the 12 L. monocytogenes isolates recovered from abattoirs, it was 25%, 8.3%, 50% and 16.7% for the serogroup 1/2a-3a, 1/2b-3b, 1/2c-3c, and 4b-4d-4e respectively (P < 0.05). All (100%) isolates of L. monocytogenes from the farms and abattoirs were positive for seven virulence genes (hlyA, inlB, plcA, iap, inlA, inlC, and inlJ). The clinical and food safety significance of the findings cannot be ignored.

Prevalence of Listeria species in raw vegetables sold in Burdur province

In this research, a total of 90 raw vegetables (spinach, broccoli, lettuce, parsley, arugula, purslane, garden cress, scallions, and mushrooms) were used as materials, each of the vegetables included 10 samples obtained from different producers and district bazaars in Burdur province. Listeria spp. was detected in 9 (10%) of a total of 90 vegetable samples. However, none of the 9 isolated Listeria spp. from this study is classified as L. monocytogenes. Antibiotic susceptibility testing by disc diffusion method showed that 100% of the isolates were susceptible to ampicillin and penicillin G while the highest resistance has been found against meropenem and erythromycin (88.88%), and trimethoprim-sulfamethoxazole (66.66%). In conclusion, raw vegetables are considered to pose a hazard to food safety and public health due to Listeria species contamination.

Prevalence of Listeria Species and Listeria monocytogenes on Raw Produce Arriving at Frozen Food Manufacturing Facilities

The ubiquity of Listeria monocytogenes in the environment affects the food industry and presents concerns for frozen food facilities. This study determined the prevalence and numbers of Listeria species and L. monocytogenes on raw produce arriving at frozen food facilities. Raw produce was collected using multilevel blinding protocols to ensure anonymity of participants and avoid traceback. Five raw vegetables were selected: corn, carrots, green beans, peas, and spinach. Raw products were collected after arrival at the facilities but before cleaning or other preprocessing steps that are typically performed inside the facility. The U.S. Food and Drug Administration's Bacteriological Analytical Manual method for detection of Listeria spp. and L. monocytogenes was followed, with PCR screening followed by selective plating methods. Listeria numbers were estimated from positive samples using the most-probable-number (MPN) methodology. A total of 290 samples were collected, with 96 and 17 samples positive for Listeria spp. (33.1%) and L. monocytogenes (5.9%), respectively. Enumeration data for the 96 Listeria spp. samples indicated 82 samples had greater than 100 MPN of Listeria spp. per g and 14 samples had less than 100 MPN Listeria spp. per g. The prevalence of Listeria spp. varied by commodity: spinach (66.7%), peas (50%), corn (32.2%), green beans (22.2%), and carrots (13%). L. monocytogenes prevalence was determined in corn (13.6%), peas (6.3%), and green beans (4.2%) arriving at processing facilities. Such data were previously unavailable to frozen vegetable processors and are valuable in implementing process control standards. The prevalence and pathogen concentration data from raw commodities found in this study can provide the industry with information to conduct more accurate quantitative risk assessments and a baseline to model and target appropriate pathogen reduction steps during processing.

Prevalence of Listeria Species on Food Contact Surfaces in Washington State Apple Packinghouses.

The 2014 caramel apple listeriosis outbreak was traced back to cross-contamination between food contact surfaces (FCS) of equipment used for packing and fresh apples. For Washington state, the leading apple producer in the United States with 79% of its total production directed to the fresh market, managing the risk of apple contamination with Listeria monocytogenes within the packing environment is crucial. The objectives of this study were to determine the prevalence of Listeria spp. on FCS in Washington state apple packinghouses over two packing seasons and to identify those FCS types with the greatest likelihood to harbor Listeria spp. Five commercial apple packinghouses were visited quarterly over two consecutive year-long packing seasons. A range of 27 to 50 FCS were swabbed at each facility to detect Listeria spp. at two sample times, (i) postsanitation and (ii) in-process (3 h of packinghouse operation), following a modified protocol of the FDA's Bacteriological Analytical Manual method. Among 2,988 samples tested, 4.6% (n = 136) were positive for Listeria spp. Wax coating was the unit operation from which Listeria spp. were most frequently isolated. The FCS that showed the greatest prevalence of Listeria spp. were polishing brushes, stainless steel dividers and brushes under fans/blowers, and dryer rollers. The prevalence of Listeria spp. on FCS increased throughout apple storage time. The results of this study will aid apple packers in controlling for contamination and harborage of L. monocytogenes and improving cleaning and practices for sanitation of the FCS on which Listeria spp. are the most prevalent.IMPORTANCE Since 2014, fresh apples have been linked to outbreaks and recalls associated with postharvest cross-contamination with the foodborne pathogen L. monocytogenes These situations drive both public health burden and economic loss and underscore the need for continued scrutiny of packinghouse management to eliminate potential Listeria niches. This research assesses the prevalence of Listeria spp. on FCS in apple packinghouses and identifies those FCS most likely to harbor Listeria spp. Such findings are essential for the apple-packing industry striving to further understand and exhaustively mitigate the risk of contamination with L. monocytogenes to prevent future listeriosis outbreaks and recalls.

Prevalence of Listeria Species and Serotyping of Listeria monocytogenes Bacteria Isolated from Seafood Samples

Listeria species are well acknowledged as causal agents of human listeriosis with foodborne appearances. Seafoods are measured as the chief sources of Listeria spp. An existing survey was performed to apprise the incidence rate of Listeria spp. as well as distribution of pathogenic serotypes amongst the Listeria monocytogenes bacteria recovered from seafood samples. Three-hundred and fifty seafood samples were obtained and cultured. Listeria isolates were recognized using biochemical and PCR techniques. Distribution of 1/2a, 1/2b and 4b serotypes were examined using the PCR. Forty out of 350 (11.42%) samples harbored Listeria Spp. Incidence of L. monocytogenes, L. ivanovii and L. seeligeri were 62.50%, 20% and 7.50%, respectively. Incidence of Listeria spp. amongst the fish, shrimp, lobster and crab samples were 14%, 12%, 13% and 8%, respectively. Incidence of L. monocytogenes amongst the fish, shrimp, lobster and crab samples were 9%, 6%, 7% and 6%, respectively. Distribution of 1/2a, 1/2b and 4b serotypes were 48%, 28% and 8%, respectively. Discoveries disclosed the latent portion of seafoods as sources of Listeria spp. and alerted to health personnel regarding the requirement for appropriate management and cooking in persons that have recognized high-risk of developing food poisoning.

Prevalence of Listeria species in dairy farms in Khartoum State (Sudan)

This is a cross sectional study conducted at Khartoum State, Sudan with the objective of investigating the occurrence of Listeria spp. in dairy farms and associated environment. One hundred and twenty dairy farms were included in the study (720 samples of milk, teats, utensils, feed, water and air were collected). Conventional microbiological methods to isolate and identify Listeria spp. were done. The overall prevalence of Listeria spp. was 14.7%. Seven species of Listeria were isolated from milk and other sources in dairy farm environment. The identified animal pathogenic Listeria spp. include. L. monocytogenes and L. ivanovii, Other isolated Listeria spp. were L. seeligeri, L. welshimeri, L. innocua. L. grayi and L. murrayi. The presence of Listeria spp. in milk were L. monocytogenes (2.5%), while 1.7% for each of L. seeligeri, L. welshimeri and L. ivanovii were found. The most frequently isolated species was L. welshimeri (33.3%). High prevalence of Listeria spp. was observed in water (24.2%) followed by teats (20.0%), feed (16.7%) and utensils (14.2%) compared to milk (7.5%) and air (5.8%). Dairy farm hygiene and environment have the significant impact on the prevalence of Listeria spp. This study concluded that diversity of the prevalence of Listeria spp. in dairy farm environment necessitates conduction of microbial risk assessment in milk value chain.

İnci Kefalinde (Chalcalburnus tarichi, Pallas 1811) Listeria Türlerinin Varlığı ve Yaygınlığı

Lake Van is not a very convenient environment for life of both sea and freshwater fish due to its high alkaline (pH 9.8) and salty (0.21%) water and only pearl mullet (Chalcalburnus tarichi, Pallas 1811) are present in the lake. In this study, the presence and prevalence of Listeria species in samples of the pearl mullet (Chalcalburnus tarichi, Pallas 1811) living as an endemic species in Lake Van and taken a total of 160 times for 12 months were examined. The method recommended by the United States Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) was used for the isolation and identification of Listeria species. Among the pearl mullet samples examined, Listeria spp. were isolated in 20 (12.50%) and of them L. innocua in 10 (6.25%) and L. welshimeri in 8 (5.00%) and L. ivanovii in 2 (1.25%) were identified. In this study, the presence of Listeria species in pearl mullet samples examined according to the seasons was revealed for the first time. Failure to identification of L. monocytogenes in any of the samples that is an important pathogen for humans, was assessed as an indicator that these fish did not constitute a public health risk in terms of listeriosis. As a result, Listeria spp. and other pathogenic microorganisms not to pose a risk to public health and in order to prevent the deterioration of fishes and reduce the economic losses, the transportation, storage and marketing of the caught fishes should be done under hygienic and cold conditions.

Prevalence of Listeria species and L. monocytogenes in ready-to-eat foods in the West Pomeranian region of Poland: Correlations between the contamination level, serogroups, ingredients, and producers

Poland is one of the largest food producers in Europe, and the West Pomeranian region of Poland is a large producer of RTE food. Thus, the objective of this study was to determine the prevalence of Listeria sp. and L. monocytogenes (LM) in RTE foods manufactured by 13 selected Polish food producers whose processing plants are located in this region. In total, 650 samples of RTE foods, and 263 ingredients of salads and desserts were analyzed. Almost 18% of the RTE foods failed to meet the zero tolerance limit for Listeria, which means they should not be allowed for retail. LM was isolated from 13.5% of the samples, with counts of 10–100 CFU/g noted in half of them. Products with meat and dairy ingredients, and fish products, sandwiches, sprouts and sushi, were at the highest statistically significant risk of LM contamination. Four serogroups were identified among the LM isolated from RTE foods, of which the 4b-4d-4e serogroup was predominating. The samples most heavily contaminated with LM contained even 2 serogroups. Results were subjected to the cluster analysis and principal component analysis to determine correlations between food groups, food ingredients, producers, contamination level, and serogroups of LM.

Prevalence of Listeria Species in Dairy Cows and Pregnant Women with Reference to Virulotyping of Listeria monocytogenes in Egypt

This study was conducted to determine the prevalence of Listeria spp . in milk and feces of dairy cows as well as stool of pregnant women in Sharkia and Dakahlia Governorates, Egypt. Three hundred and fifty samples including; normal raw milk (n=200), mastitis milk (n=50), feces of dairy cattle (n=50) and stool of pregnant women (n=50) were randomly collected. Listeria spp. were isolated on Oxford agar and then subjected to biochemical and molecular identification. The overall isolation rate of Listeria spp. was 16%. The prevalence rates of Listeria monocytogenes were 8%, 4%, 2% and 4% in feces of dairy cows, normal milk, mastitis milk and stool of pregnant women, respectively. The prevalence of L. ivanovii and L. welshimeri in milk of dairy cows were 6% and 4%, respectively. L. monocytogenes isolates were molecularly confirmed to the species level by amplification of 16S rRNA gene. The distribution of internalin A (inlA) and internalin B (inlB) was determined in 15 identified L. monocytogenes isolates. The overall prevalence of inlA gene and inlB gene in L. monocytogenes isolates from different sources were 80% and 40%, respectively. Two L. monocytogenes isolates from normal raw milk and feces of dairy cows didn’t harbor both inlA and inlB genes. Listeria spp. isolated from normal milk, feces, mastitis milk and stool of pregnant women, potentially can cause human illness and abortion in pregnant women. Internalin (A&B) genes are considered the best indicator for virulence determination of L. monocytogenes isolated from different sources.

Optimization and Molecular Detection of Neuraminidase Gene in Listeria Monocytogenes

Background: Listeria monocytogenes is one of the human pathogenic microbes causing Listerosis and is usually found as a contaminant in many foods and dairy samples. Neuraminidases (NAs) plays a key role in many pathogenic bacteria and has the ability to block sialic acid (a virulence factor) that targets mucosal surfaces. Objectives: In the current study, NA or sialidase-producing Listeria monocytogenes were screened from different milk samples of cow. Methods: Listeria monocytogenes was identified by morphological, biochemical, and hlyA gene polymerase chain reaction (PCR) assay. Furthermore, molecular detection of 432 bp amplicon of sialidase enzyme (Neuraminidase) gene in the native isolates was noted. Results: The prevalence of Listeria species was found to be around 4.16%. Sialidase enzyme was found to be produced in high amounts in isolated L. monocytogenes. Furthermore, NA was purified by ammonium sulphate precipitation and gel filtration techniques. The partially purified sialidase enzyme possessed a molecular mass of 27.0 ± 1 with an isoelectric point of 7.6. The optimum pH and temperature were 4.6 to 8.2 and 30 to 35°C, respectively. The enzyme had no effect on metal ions, such as Mn+2, Zn+2, and Ca+2, whereas Hg+2 and Al+3 had potentially acted as inhibitors. Conclusions: This study suggests that the sialidase of L. monocytogenes plays a significant role in its pathogenesis.

Multidrug Resistant Listeria Species from Milk and Milk Products

A total of 295 samples from milk (110), kalaari (110), ice-cream (75) were analysed to reveal the prevalence of Listeria species in and around Jammu. The overall prevalence of Listeria species was 8 (2.71 %). Listeria monocytogenes was isolated from 7 samples (2.37 %) which included 3 (2.72 %) in milk, 4 (3.63 %) in kalaari and one isolate of Listeria ivanovii (4.54 %) from ice-cream. The prevalence was higher in winter months (p < 0.05). All isolates of L. monocytogenes (n = 7) and L. ivanovii (n = 1) were hemolytic and Christie, Atkins, Munch-Peterson tests were positive while 5 L. monocytogenes, one L. ivanovii were phosphatidylinositol specific phospholipases C positive. All Listeria isolates were sensitive to Amoxicillin + Sulbactam Ampicillin, Erythromycin and Enrofloxacin, Levofloxacin, Gentamycin and multidrug resistant to Amikacin, Cephalexin, Cefixime, Cefuroxime and Oleandomicin.

Preliminary studies on the prevalence of &lt;i&gt;Listeria monocytogenes&lt;/i&gt; in &lt;i&gt;Clarias gariepinus&lt;/i&gt; and &lt;i&gt;Orechromis niloticus&lt;/i&gt; in Ibadan, Oyo state

Prevalence of Listeria species in Clarias gariepinus and Oreochromis niloticus were examined. Sixty (60) of fishes were randomly selected from commercial outlet in Ibadan. Sex, Total Length, and Weight were determined. Simple percentages were used to analysis the data. The results show that 12 out of 60 (20%) were positive for Listeria species. Male has highest number of infection (18.91%) fishes with average length of 20-30cm had 41.17%, 351-400g had highest number of infection (28.57% ). C. gariepinus (26.67%) shows the higher presence of Listeria species than O. niloticus. There is no correlation between infection and species, sex or length. The result shows high presence of Listeria species and further suggested that there is high risk of contacting listeriosis though the listeriosis outbreak has not been recorded in the study area.Key words: Listeria species, Prevalence, Infection

Cover Caption

Journal of Food ScienceVolume 80, Issue 5 p. i-ii ContentFree Access Cover Caption First published: 08 May 2015 https://doi.org/10.1111/1750-3841.12621AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract April Online Cover: Dumplings with various fillings, from “Effect of Filling Type and Heating Method on Prevalence of Listeria species and Listeria monocytogenes in Dumplings Produced in Poland” by Barbara Szymczak and Waldemar Da¸browski; photo credit: Mariusz Szymczak; p. M1061. Volume80, Issue5May 2015Pages i-ii RelatedInformation

Prevalence of Listeria species in Fresh Salad Vegetables and Ready-to-Eat Foods Containing Fresh Produce Marketed in Canterbury, New Zealand

Fresh produce, the most common food, is source of high value nutrients in human diet. However, some pathogenic bacteria associated with fresh produce may cause illness. For example, Listeria monocytogenes is a microorganism that causes a disease of variable severity, such as mild gastroenteritis, severe infections of the blood stream and/or the central nervous system, and even leads to abortion in pregnant women. The aim of this study was to determine the prevalence of Listeria spp. in fresh produce. Four common fresh vegetables (lettuce, car- rot, purple cabbage, green cabbage) were tested in the amount of Listeria spp. over a 5-week period, and eight individual samples of each fresh vegetable were collected from two fruit and vegetable markets each week. Listeria spp. were detected in all the purple cabbage samples col- lected from these two markets. Listeria spp. were also present in 60% and 100% of the green cabbage samples obtained from market 1 and market 2, respectively. Listeria spp. were found in the lettuce samples collected from both markets during week 1 to week 3. Carrot samples had the lowest percentage (20%) of Listeria spp. Generally Listeria spp. were present in all the four vegetables sampled. However, variations were recorded between vegetable types and sources. Selected ready-to-eat products containing fresh produce were also collected to test the presence of Listeria spp. and it turned out that two samples were Listeria spp. positive. Our data sug- gested that Listeria spp. were generally prevalent in fresh vegetables and Ready-to-Eat (RTE) food products containing fresh produce.

Prevalence of Listeria Species in Environment and Milk Samples

The previous notion that infection by pathogenic Listeria (listeriosis) is not an important health problem in India starts to be revised now, mainly due to changing habits of the production, distribution and storage of food, favoring the multiplication and spread of cold–tolerant bacteria like Listeria. Despite this altering scenario, data on the prevalence of Listeria on the Indian subcontinent are still rather sporadic. We investigated the occurrence of Listeria species in environmental and raw milk samples from Mysore city (moderately hot, semi–arid climate). Environmental samples included cow dung from cowshed, grazing pasture and soil samples from vegetable–cultivation land. Cold enrichment was used to recover Listeria species from raw cow milk (from individual animals) (n=130), cow dung (collected from individual animals) (n=130) and soil (n=100) samples. 10 g sample in case of cowdung and soil and 10mL in case of milk were transferred to 90 mL BHI broth and incubated at 4oC for two weeks. Aliquots from the enriched broth were streaked on Oxford and PALCAM plates, at weekly intervals. Listeria isolates were subjected to phenotypic and genotypic characterization. Phenotypic characterization included standard biochemical tests such as catalase test, motility at 25 °C and 37 °C, acid production from the canonical panel of carbohydrates, nitrate reduction, esculin hydrolysis, methyl red and Voges Proskauer reaction. Genus– and species–specific primers were used for PCR differentiation of the isolates. L. ivanovii was isolated from 1% of the soil samples, L. seeligeri from 0.76% of the cowdung samples and L. innocua from 0.76% of the raw milk samples tested. Strategies to reduce the incidence of Listeria in environment and milk samples should be implemented.

Prevalence of Listeria species in raw hamburger meatballs and chicken burgers in eastern Turkey

The aim of this study was to determine the prevalence of Listeria spp. in raw hamburger meatballs and chicken burgers obtained from different fast-food and markets in Elazig and Malatya Provinces in the east of Turkey during 2010 and 2011. A total of 71 samples, consisting of 35 samples of raw hamburger meatballs and 36 samples of chicken burgerswere investigated for the presence of Listeria spp. by culture method and a polymerase chain reaction assay targeting the listeriolysin O sequence for L. monocytogenes. We found that 34.3, 22.9, 5.7 and 5.7%, respectively of hamburger meatballs tested positive for Listeria spp., L. innocua, L. monocytogenes and L. welshimeri, respectively. However, 58.3, 33.3, 13.9, 8.3 and 2.8% of chicken burgers were found to be positive for Listeriaspp., L. innocua, L. monocytogenes, L. grayi and L. welshimeri, respectively. L. innocuawas isolated more frequently than the other species. This study shows the need for carefully evaluating the risk to acquire listeriosis from consumption of raw hamburger meatballs and chicken burgers. Key words: Listeria spp, Listeria monocytogenes, raw hamburger meatballs, chicken burgers, polymerase chain reaction.

Prevalence of Listeria species in retail quail products from Isfahan, Iran

Listeria species are Gram positive, short, non sporing rods, microaerophilic. Of the six species currently recognized, Listeria monocytogenes is the most important as it causes a range of infections in humans and animals. This study was undertaken to determine the occurrence of Listeria spp. in retail quail products in Isfahan, Iran. A total of 150 samples of meat, liver, heart, kidney, and feces of quail were obtained from retail stores in Isfahan, and analyzed using standard culture methods and biochemical tests. Out of the total 150 samples, 10 (6/6%) were positive in Listeria spp. The occurrence of Listeria spp. in samples of meat, liver, heart, kidney, and feces was 10, 3, 0, 0, and 20% respectively. Only one sample was contaminated with L. monocytogenes (0/6%) and other samples were contaminated with Listeria innocua(6%). Key words: Quail, culture method, Listeria species.

Prevalence and antibiotic resistance of Listeria species in food products in Taipei, Taiwan

A total of 400 samples including meat products, dairy and dairy products, fresh vegetables, fresh seafood, and ready-to-eat food products from supermarkets in Taipei area were collected and analyzed for the prevalence of Listeria species. The overall occurrence ofListeria spp. was 16.5%, and most of them were isolated from meat products and vegetables. Listeria monocytogenes was isolated from 22 out of the 400 (5.5%) samples studied. Other species found were Listeria innocua (7.5%), Listeria ivanovii (1%), Listeriaseeligeri (0.5%), Listeria grayi (0.5%) and Listeria welshimeri (1.5%). The possibility of antibiotic resistance of the 66 isolated Listeria spp. was also examined by the standard disk diffusion method. L. monocytogenes strains isolated from food sample were treated with 8 antibiotics currently used in human or domestic animal therapy. Considering the fact that L. monocytogenes is slowly becoming antibiotic resistant, a continuous examination of emerging antimicrobial resistance of this pathogen is important to ensure effective treatment of human listeriosis. Overall, Listeria spp. was resistant to penicillin (7.58%), chloramphenicol (3.7%) and tetracycline (1.96%), but sensitive to amoxicillin, vancomycin, ampicillin, rifampicin and sulfamethoxazole. The results in this study are helpful in enriching the data on antibiotic resistance of strains isolated from food and in developing effective risk management strategies. Key words: Listeria spp., Listeria monocytogenes, moxicillin, vancomycin, ampicillin, rifampicin.

Disinfectant effect of Methylated Ethanol against Listeria species

This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol) as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2) raw milk samples from different lactating cows within Sokoto metropolis (Nigeria). 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The samples were analyzed using selective culture and isolation technique in which the 288 samples collected before disinfection, 114 (39.6%) were positive for Listeria species. Among the positive samples 44 (38.6%) were Listeria innocua, 16 (14.0%) Listeria ivanovii, 36 (31.6%) Listeria monocytogenes, 11 (9.6%) Listeria welshimeri and 7 (6.1%) Listeria seeligeri, while none of the 288 samples collected after disinfection was positive. The study has shown high prevalence of Listeria species in milk collected without washing/disinfecting the teats and has also established the sensitivity of Listeria species to methylated ethanol which can be used as dip for disinfecting udder teats before milking in order to prevent contamination with Listeria species and other methylated spirit-sensitive organisms. This study is essential to educate Fulani herdsmen and other milk handlers on the importance of disinfecting udder teats before milking.

Prevalence of Listeria species including L. monocytogenes from apparently healthy animals at Baroda Zoo, Gujarat State, India

Listeriosis is a infectious bacterial disease of domestic and wild animals and humans. A total of 56 faecal samples were collected from mammals and birds at Baroda Zoo, Vadodara, Gujarat State, India. Confirmation of the isolates was based on biochemical tests followed by phenotypic characterization by hemolysis on sheep blood agar, Christie Atkins Munch-Petersen (CAMP) test, phosphatidylinositol-specific phospholipase C (PI-PLC) assay and phosphatidylcholine-specific phospholipase C (PC-PLC) assay. The isolates were subjected to genotypic characterization with the help of polymerase chain reaction (PCR) assay for five virulence-associated genes, plcA, prfA, hlyA, actA and iap. Listeria monocytogenes isolates were further subjected to multiplex-PCR based serotyping. From 56 samples three (5.36%) were found positive for Listeria spp. of which one (1.79%) was identified as L. monocytogenes and two (3.57%) were identified as L. innocua. The isolate of L. monocytogenes was hemolytic, CAMP positive, PI-PLC positive, hlyA, pclA and prfA positive by PCR and turned out to be PC-PLC positive and was serotyped as 4b.