Bacteriological Quality of Ready-Mixed Mink Feed in Finland

Frozen samples of Finnish ready-mixed mink feed were analyzed for total bacterial count, the number of faecal streptococci, the coliform count, the number of haemolytic bacteria and the number of sulphite-reducing bacteria. The investigation comprised 242 feed samples from 38 central kitchens and larger private farm kitchens, the combined feed production of which is about 85 % of the yearly feed production of Finland.Of all samples 48.3 % had a total bacterial count of 10⁶ … 6} × 106 bacteria per g of feed. The total bacterial count was relatively constant during the first four production periods of the year (December-August) and was elevated during the last period (September-November). The percentage of samples containing less than 2.5 × 10⁴ faecal streptococci per g of feed was 49.8 %; 62 % of the samples contained less than 2.5 × 10⁴ coliform bacteria per g. The content of coliform bacteria was lowest during the third production period (May); 48.5 % of the samples contained 5 × 10³ … 10⁵ haemolytic bacteria per g, and 4.6 % were negative. The content of haemolytic bacteria was relatively constant during the whole production year; 52.6 % of the feed samples contained 5 × 10³ … 10⁵ sulphite-reducing bacteria per g, and 17.2 % were negative. The mean content of sulphite-reducing bacteria was lowest during the second production period (March-April).The results are discussed and compared with corresponding results from Norway and Denmark.     

Antimicrobial resistance in Enterococcus spp. and Escherichia coli isolated from poultry feed and feed ingredients

Poultry feed is at the start of the food safety chain in the "farm-to-fork" model, and might serve as a source of antimicrobial resistant bacteria present in poultry meat. Antimicrobial resistance was investigated in 1137 enterococci and 163 Escherichia coli strains recovered from 23 samples of commercial broiler feed and 66 samples of raw feeding materials taken over half a year timespan. Enumeration of enterococci and E. coli were also performed using traditional plating and fluorescent in situ hybridisation methods. Viable enterococci were detected in all feed samples and in 66% of samples of separate feed ingredients, while E. coli was present in 50% and 32% of feed and raw feeding materials, respectively. The median values (50th percentile) for plate and FISH counts for feeds were, respectively, 2.70 log CFU/g and 5.52 log cells/g for enterococci, and 0.15 log CFU/g and 6.00 log cells/g for E. coli. Among enterococci recovered from feed ingredients, resistance to rifampicin, erythromycin, nitrofurantoin, tetracycline, and ciprofloxacin was found in 59.8%, 21.6%, 21.2%, 18.0% and 6.9% of the isolates, respectively. A considerable proportion of the enterococci isolates obtained from broiler feed displayed resistance to tetracycline (69.1%), rifampicin (58.5%), erythromycin (52.9%) and nitrofurantoin (36.2%). Lower percentage of resistance was observed to chloramphenicol (4.6%), ciprofloxacin (3.9%), vancomycin (1.9%) and ampicillin (1.2%). Among E. coli recovered from feed ingredients and poultry feeds, resistance to ampicillin, tetracycline and streptomycin was found in 22.9%, 27.6% and 19.0% and in 22.4%, 41.4% and 17.0% of the isolates, respectively. These data show that feedstuffs and poultry feeds are extensively contaminated by resistant enterococci and, in a lesser extent, by E. coli, thus leading to their introduction in the farm environment.     

Prevalence, numbers and antimicrobial susceptibilities of Salmonella serovars and Campylobacter spp. in retail poultry in Phnom Penh, Cambodia

Salmonella and Campylobacter are common bacterial pathogens associated with human gastro-enteritis; and raw poultry is considered to be an important source of these bacteria. To evaluate whether the Salmonella serovars and Campylobacter spp. bacteria could be monitored for the purpose of microbial presence, enumeration and antimicrobial resistance in raw poultry, 152 poultry carcasses were randomly selected from 10 markets in retail outlets of Phnom Penh during March 2006 to February 2007. The majority of poultry samples was contaminated by Salmonella serovars (88.2%) and Campylobacter spp. (80.9%). A very high contamination of Salmonella was found at 3-4 log?? CFU/g for 22.4% of samples and of Campylobacter at 7-8 log?? CFU/g for 1.3% of samples. Fifty nine different Salmonella serovars contaminated 134 poultry carcasses; five most prevalent serovars covered 29.1% of serovars isolates (Anatum, Typhimurium, Corvallis, Stanley and Enteritidis). Three Campylobacter species contaminating 123 raw poultry were Campylobacter jejuni (50.0%), Campylobacter coli (29.0%) and Campylobacter lari (21.0%). High antibiotic resistance percentages were found among Salmonella serovars and Campylobacter spp. isolates. This study revealed that raw poultry at the retail outlets in Phnom Penh markets are contaminated with high prevalences of food-borne pathogens, and communicating the importance of minimizing this risk in reducing human infections.     

The isolation of salmonella from kangaroos and feral pigs processed for human consumption

A total of 154 feral pig carcases and 81 kangaroo carcases were examined for the presence of Salmonella, coliforms and total aerobic counts. Approximately 34% of pig carcases yielded one or more serotypes of Salmonella, while about 11% of kangaroo carcases were contaminated with salmonella. The results differed widely between sampling occasions. A total of 13 serotypes were isolated from feral pigs with S. anatum (31 isolates) and S. typhimurium (9 isolates) being the predominant serotypes. Coliforms were isolated from approximately 90% of carcases. The mean log10 coliform count on feral pigs was 4.39 +/- 1.45/g and the mean log10 total count was 6.15 +/- 1.15/g. About 21% of carcases were contaminated with more than 100,000 coliforms/g. A total 3 serotypes were isolated from kangaroos (S. bahrenfeld, S. binza, and S. onderstepoort). The mean log10 coliform count on kangaroos was 3.54 +/- 1.04. More than 50% of kangaroo carcases were contaminated with less than 100 coliforms/g. About 15% of carcases were contaminated with more than 10,000 coliforms/g. The mean log10 total count was 5.2 +/- 1.01/g.     

Enterotoxigenicity of staphylococci isolated from raw milk obtained from settled and nomadic herds around Zaria, Nigeria

Staphylococcal isolates from 135 raw milk samples obtained from settled herds (42) and nomadic herds (93), were characterized and assayed for enterotoxin production. Of the 42 samples from settled herds, 13 (31%) were California Mastitis Test (CMT)-positive, but all the samples contained staphylococci. Only 3 (3.2%) of the 93 raw milk samples from nomadic herds were CMT-positive but 58 (62.4%) contained staphylococci. Of the 13 isolates from CMT-positive milk obtained from settled herds, one produced enterotoxin A, while amongst the 29 from CMT-positive milk, 4 elaborated enterotoxin A and 3 produced type D. None of the isolates from milk obtained from nomadic herds was enterotoxigenic.     

One year investigation of the prevalence and diversity of clostridial spores in raw milk from the Tokachi area of Hokkaido

We investigated the seasonal prevalence and diversity of clostridial spores in raw milk from the Tokachi area of Hokkaido. Samples of raw milk were collected quarterly from May 2013 through February 2014. The mean clostridial spore count for the raw milk from 336 milk tankers was 27.6 CFU/100 ml. The clostridial species isolated most frequently from raw milk samples was Clostridium tyrobutyricum. The dominant species was C. tyrobutyricum regardless of the season. The percentage of samples with low spore counts (<10 CFU/100 ml) was highest (60.9%) during winter (February) and lowest (34.5%) in autumn (November). In comparison, the percentage of samples with high spore counts (>100 CFU/100 ml) was highest (5.7%) in autumn (November) and lowest (1.1%) during spring (May).     

鹿场环境中细菌的分布及耐药性调查

为探究辽宁省西丰县鹿场环境中细菌的分布及耐药性情况,本试验采集了鹿场粪便、饮水、空气、饲料等样品,进行了细菌的分离培养及鉴定,对分离到的菌株16S rDNA基因进行PCR扩增、测序分析,并对分选出的致病菌和条件致病菌进行药敏试验。结果显示,所测样品共分离纯化出27株菌,公鹿精饲料、母鹿精饲料、粗饲料和水的含菌量分别为1.0×10⁵、8.7×10⁴、2.7×10⁷ CFU/g和2.9×10⁴ CFU/mL,表明水和粗饲料不符合国家规定的养殖场环境卫生要求;16S rDNA基因序列在NCBI比对后,鉴定出有大肠埃希菌、志贺氏菌等15种不同菌株,其中致病菌和条件致病菌共13种,这13种细菌对呋喃唑酮、多黏菌素B和头孢氨苄等耐药,对头孢曲松、环丙沙星和丁胺卡那等药物敏感。本试验结果可为鹿场细菌性疾病的防控及用药提供参考依据。     

Isolation of Campylobacter spp. from semen samples of commercial broiler breeder roosters

Pooled semen samples from 12 groups of mature commercial broiler breeder roosters were analyzed for the presence of Campylobacter. Each of the 12 groups was comprised of eight individuals and was sampled weekly for five consecutive weeks. Once a day, roosters were allowed to have a restricted amount of feed after the semen samples were collected by abdominal massage. This feeding schedule reduced the amount of fecal contamination in and around the vent as well as in the semen sample. For replications 1, 2, and 3, the numbers of Campylobacter-positive groups were 8, 5, and 5, respectively, out of 12. For replications 4 and 5, 6 of 8 and 6 of 11 groups were positive, respectively. Only two groups were positive for Campylobacter at all sampling times, two groups were negative each time, and eight groups produced variable results. Also, fecal droppings, external swabs of the genitalia, and semen samples were taken from individual roosters between 49 to 65 wk of age. Of the total 275 semen samples collected, 9.47% contained naturally occurring Campylobacter, whereas 9.6% of 114 fecal droppings and 7.9% of the 114 genital swabs were positive. Levels of the organism present in the fecal samples ranged from 1.0 to 4.2 log colony-forming units (CFU)/g with an average of 2.9 log CFU/g feces. For semen, the levels ranged from as low as enrichment recovery only to as high as 3.1 log CFU/ml of semen with an average of 1.2 log CFU/ml. For swabs of genitalia, the levels of Campylobacter were so low that recovery was achieved only through enrichment. These data suggest that rooster semen may serve as a vehicle for transmission of Campylobacter to the reproductive tract of the hen and subsequently to the fertile egg.     

Survey on the Listeria contamination of ready-to-eat food products and household environments in Vienna, Austria

Qualitative and quantitative contamination of ready-to-eat food-stuffs with the pathogen Listeria monocytogenes was studied in 1586 samples collected from 103 supermarkets (n = 946) and 61 households (n = 640) in Vienna, Austria. Seventeen groups of ready-to-eat foods were classified into three risk categories for contamination (CP1-CP3). Three to four samples were randomly collected at the retail level from each CP. Regarding the households, the sampling procedure was started with food items of CP1, and if not available, was continued with sampling of food items of CP2 and finally of CP3. Additionally, 184 environmental samples (swabs from the kitchen area, dust samples from the vacuum cleaner) and faecal samples (household members and pet animals) were included. One-hundred and twenty-four (13.1%) and 45 (4.8%) samples out of 946 food samples collected from food retailers tested positive for Listeria spp. and L. monocytogenes, respectively, with five smoked fish samples exceeding the tolerated limit of 100 CFU/g food. Food-stuffs associated with the highest risk of contamination were twice as frequently contaminated with L. monocytogenes as food-stuffs associated with a medium risk of contamination. Products showing the highest contamination rate were fish and seafood (19.4%), followed by raw meat sausages (6.3%), soft cheese (5.5%) and cooked meat products/patés (4.5%). The overall contamination rate of foods collected at the household level was more than two times lower. Only 5.6% and 1.7% of 640 food-stuffs analysed tested positive for Listeria spp. and L. monocytogenes, respectively. However, CP1 foods were rarely collected. Pulsed-field gel electrophoresis (PFGE) typing of the collected L. monocytogenes isolates revealed a high degree of diversity between the isolates, with some exceptions. PFGE typing of isolates harvested from green-veined cheese revealed a match among strains, although the manufacturer seemed to be distinguishable. Typing of household strains revealed an epidemiological link within one family. In this case, food-stuffs and the kitchen environment were contaminated by an indistinguishable isolate. In addition, the same isolate was collected from a pooled faecal sample of the household members suggesting that consumption of even low contaminated food items (<100 CFU/g) results in Listeria shedding after the passage through the gut.     

Bacteriological investigation on “Mauro” sold in Catania

Seaweeds known as “Mauro” are traditionally used fresh or to prepare omelettes in Sicily (Italy). Twenty samples sold in Catania between May 2005 and September 2007 were analyzed for Escherichia coli, Total Enterobacteria, Aeromonas spp., Pseudomonas spp., Vibrio spp., and Salmonella spp. Thirty Vibrio strains were examined for the presence of the virulence genes, toxR, toxRS, tl, tdh, and trh in the genomes of the isolates. Total Enterobacteria ranged between 2.23 and 6.85 log CFU/g, and in six samples, E. coli ranged between 0.70 and 2.74 log CFU/g. Aeromonas spp. was present in samples between 1.0 and 5.90 log CFU/g, while Pseudomonas spp. ranged between 2.70 and 7.27 log CFU/g. Vibrio spp. was present in 75% of samples at values between 1.30 and 4.60 log CFU/g. The most frequently isolated species was V. alginolyticus (76.66% of isolates), of which 82.60% were positive for toxR and the remaining 17.40% of strains were positive for toxRS. V. parahaemolyticus was identified in 13.33% of strains; all were positive for toxR and, in one case, for both toxR and toxRS. V. coralliitycus was isolated in 6.66% of strains (all positive for toxR), and one was identified as V. mimicus (positive for toxRS). The results of this study suggest that there is need for stringent quality control during harvesting and distribution of Mauro.

     

16种植物性饲料原料中黄曲霉毒素B1、T-2毒素、赭曲霉毒素A、伏马毒素(B1+B2)污染调查检测及控制建议

为掌握黄曲霉毒素B1、T-2毒素、赭曲霉毒素A、伏马毒素(B1+B2)在植物性饲料原料中的污染状况,指导帮助饲料企业和养殖企业开展霉菌毒素防控,降低霉菌毒素对饲料产品质量及畜禽养殖产品危害,减少经济损失,2020年对16种60份植物性饲料原料进行调查采样,采用液相色谱—串联质谱法、免疫亲和柱净化—高效液相色谱法检测,依...     

Bacteriological quality of raw cow's milk from four dairy farms and a milk collection centre in and around Addis Ababa

Bacteriological quality of raw cow's milk taken at different sampling points from four dairy farms and a milk collection centre in and around Addis Ababa was evaluated. Milk samples were aseptically collected from udder, bucket, storage container before and after cooling and upon arrival at the processing plant. A high increase in the mean total aerobic plate count was observed in milk samples taken from the bucket (1.1 x 10(5) cfu/ml), storage container before cooling (4 x 10(6) cfu/ml) and upon arrival at the processing plant (1.9 x 10(8) cfu/ml). The mean coliform counts ranged from 1.3 x 10(4) cfu/ml (storage container before cooling) to 7.1 x 10(4) cfu/ml (upon arrival at the processing plant). The hygienic quality of raw milk from the collection centre was poor with a mean total bacterial count of 1.3 x 10(7) cfu/ml. Milk sampled from the udder contained mainly staphylococci and micrococci as udder-specific bacteria, while samples taken at later stages were additionally contaminated with bacteria of environmental origin (especially Enterobacteriaceae). Lack of knowledge about clean milk production, use of unclean milking equipment and lack of potable water for cleaning purposes were some of the factors which contributed to the poor hygienic quality of raw milk in the study farms.     

水貂膨化配合饲料筛选试验

采用对动、植物性饲料干、湿法膨化技术的加工工艺 ,配制成水貂膨化配合饲料 ,与新鲜鱼、肉搅碎后 ,再加入蒸、煮或炒熟的玉米、大豆 ,形成糊状饲料进行饲养水貂的不同饲料配方正交筛选试验。试验设计选用L4(2 3 )正交表 ,设置三因素 ,每因素二水平。试验动物选择纯种美洲标准貂 ,在生长前期、冬毛生长期分别进行了 89d与 5 9d的正交试验。试验结果表明 ,各因素极差值对影响日增重的主次关系估计为C >B >A ;B、C因素与A因素已达到显著水准 (P <0 0 5 ) ,B、C因素之间无显著差异。     

Shedding of food-borne pathogens and microbiological carcass contamination in rabbits at slaughter

To obtain microbiological data from rabbits at slaughter, 500 fecal samples and 500 carcasses samples were examined. All samples tested negative for Listeria and Salmonella. Campylobacter were detected in two fecal samples. Of the 500 fecal samples, 45.8% tested positive for eae (intimin), 1.2% for stx (Shiga toxin), and 1.8% for both eae and stx. By colony hybridization, 56 eae positive Escherichia coli strains were isolated. Among them, 27 strains (48.2%) were of the serotypes O178:H7 and O153:H7, whereas 15 strains (26.8%) belonged to a serogroup that has not yet been described (O(CB10681):H7). All strains possessed intimin beta1 and the translocated intimin receptor (tir) capable of being tyrosine phosphorylated. None of the strains harbored the genes for Shiga toxins, EAST1 (astA), bundlin (bfpA), or the EAF plasmid. Slaughter rabbits therefore constitute a reservoir for certain atypical enteropathogenic Escherichia coli. On rabbit carcasses, average total bacterial counts accounted for 3.3 log CFU cm(-2). Enterobacteriaceae and coagulase positive staphylococci (CPS) were detected on 118 (23.6%) and 153 (30.6%) carcasses, respectively. Enterobacteriaceae and CPS counts of positive samples were mainly <1.5 log CFU cm(-2). Among 153 selected CPS isolates, 98.7% were identified as Staphylococcus aureus. None of the 151 isolated strains harbored the gene for methicillin resistance (mecA). Genes for staphylococcal enterotoxins (SE) were detected in 102 strains. The combinations of seg and sei (53 strains) and sed, seg, sei, and sej (27 strains) dominated.     

Microflora of two different types of poultry litter

1. The microbiological composition of litter (straw and wood shavings) was sampled, prior to placing 1-d-old chicks, during housing of the birds and after depopulation. Two independent trials were conducted. 2. The total aerobic plate count (APC) was determined and the predominant microflora of the samples was identified using flow charts. 3. Before chick placement, the APC of wood shavings (about 4.0 log/g) was lower than the APC of straw (about log 7.5/g). With stocking, in both types of litter the APC increased to about log 9.76/g straw-litter and log 9.89/g wood shavings, respectively. After depopulation, the APC remained high (> log 9 in both types of litter) within the period of observation. 4. From both experiments, 1981 isolates were collected and identified, most of them were Gram-positive. During stocking the birds, the number of Gram-positive isolates (in particular Gram-positive irregular rods and Micrococcaceae) increased; after depopulation it stayed at that high value, whereas the number of Gram-negative isolates remained low. In both types of litter the isolates were obtained in a comparable proportion.     

Clinical, bacteriological and therapeutic aspects of bovine mastitis caused by aerobic and anaerobic pathogens.

Twenty cows and three heifers with summer mastitis-like signs were included in the study. Forty aerobic and 38 anaerobic bacterial isolates representing 23 different species were isolated from udder secretions, the mean number of species being 3.4/sample. Pathogens most often were recovered in quantities exceeding 10(5) CFU/ml. Growth of pathogenic bacteria in the blood was found in only one case. Most cases occurred in housed animals and had often been preceded by teat injury. No anaerobic growth was found in milk samples of a control group consisting of 29 cows with ordinary acute mastitis. Values of indicators of inflammation in milk (NAGase and plasmin activity) were high, mean values being 914.1 and 1.3 units. The animals with aerobic/anaerobic mastitis were treated using various antimicrobial agents. All but three quarters were lost to milk production. Two animals with complete recovery were given a combination of penicillin G and tinidazole.     

PCR detection of staphylococcal enterotoxin genes in Staphylococcus aureus strains isolated from raw and pasteurized milk

Milk is considered a nutritious food because it contains several important nutrients including proteins and vitamins. Conversely, it can be a vehicle for several pathogenic bacteria such as Staphylococcus aureus. This study aimed to analyze the frequency of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI and SEJ in S. aureus strains isolated from raw or pasteurized bovine milk. S. aureus was found in 38 (70.4%) out of 54 raw milk samples at concentrations of up to 8.9 x 10(5) CFU/ml. This microorganism was present in eight samples of pasteurized milk before the expiration date and in 11 samples analyzed on the expiration date. Of the 57 strains studied, 68.4% were positive for one or more genes encoding the enterotoxins, and 12 different genotypes were identified. The gene coding for enterotoxin A, sea, was the most frequent (16 strains, 41%), followed by sec (8 strains, 20.5%), sed (5 strains, 12.8%), seb (3 strains, 7.7%) and see (2 strains, 5.1%). Among the genes encoding the other enterotoxins, seg was the most frequently observed (11 strains, 28.2%), followed by sei (10 strains) and seh and sej (3 strains each). With the recent identification of new SEs, the perceived frequency of enterotoxigenic strains has increased, suggesting that the pathogenic potential of staphylococci may be higher than previously thought; however, further studies are required to assess the expression of these new SEs by S. aureus, and their impact in foodborne disease. The quality of Brazilian milk is still low, and efforts from the government and the entire productive chain are required to attain consumer safety.     

Growth Model of a Plasmid‐Bearing Virulent Strain of Yersinia pseudotuberculosis in Raw Ground Beef

The growth kinetics of virulence plasmid‐bearing Yersinia pseudotuberculosis (YPST) in sterile ground beef were studied at temperatures ranging from 0 to 30°C. In irradiated sterile ground beef, YPST replicated from 0 to 30°C, with corresponding growth rates (GR) ranging from 0.023 to 0.622 log CFU/h at 0–25°C, and the GR was 0.236 log CFU/h at 30°C. The maximum population densities (MPD) ranged from 8.7 to 11.0 log CFU/g. The growth and MPD of YPST were reduced significantly at 30°C. Models for GR and MPD of YPST in raw ground beef (RGB) as a function of storage temperatures were produced and displayed acceptable bias and accuracy. The models were validated with rifampicin‐resistant YPST (rif‐YPST) in sterile ground beef stored at 4, 10 and 25°C. The observed GR and MPD were within 95% of the predicted values. When compared to non‐sterile retail ground beef, the growth of rif‐YPST was not inhibited and displayed similar GR at 0, 10 and 25°C and MPDs as sterile ground beef at 10 and 25°C. Moreover, there was no loss of virulence plasmid in YPST during its growth in ground beef indicating that RGB contaminated with virulence plasmid‐bearing YPST could cause disease due to refrigeration failure, temperature (10–25°C) abuse, and if the meat was not properly cooked.     

Observations on intramammary infections in first calf heifers in early lactation

Intramammary infections and mastitis were monitored on four occasions at three-week intervals in 61 first calf heifers in five dairy herds during the first ten weeks of lactation. Of 940 quarter milk samples examined 65% were classed as negative, 10.4% as positive for mastitis (mainly subclinical), 1.8% as group 3 (infection present but no elevation in somatic cell count) and 22.8% as group 4 (elevated somatic cell count). Seventy-seven percent of the infections detected and identified were those due to coagulase-negative staphylococci, the main species being S. hyicus, S. epidermidis, S. simulans and S. hominis. Other infections detected with Corynebacterium pyogenes (three samples), Escherichia coli (one sample), Micrococcus spp. (one sample), S. aureus (two samples) and Streptococci (non-agalactiae) (seven samples).The geometric mean somatic cell count for 23 quarters infected with coagulase-negative staphylococci was 311 x 10(3) cells / mL compared to 134 x 10(3) cells / mL in noninfected adjacent contralateral quarters. The respective figures for% cell volume in Channel 8 (mainly neutrophils) were 10.6% and 3.5%. There was a highly significant association between herd and the proportion of quarter milk samples in the four mastitis categories.