Microbiological quality of ayib, a traditional Ethiopian cottage cheese

One-hundred samples of ayib, a traditional Ethiopian cottage cheese, were purchased from Awassa market and analysed for their aerobic mesophilic counts, psychrotropic counts, yeasts and molds, coliforms, spore-formers, enterococci, lactic acid bacteria, Listeria monocytogenes, staphylococci and Bacillus cereus. The majority of the samples showed counts of mesophilic aerobic bacteria, yeasts and enterococci of 10⁸, 10⁷ and 10⁷ cfu/g. About 55% of the samples were positive for coliforms and faecal coliforms. Listeria spp. were not detected in any of the samples. B. cereus and S. aureus were isolated at varying frequencies but at low numbers (10²–10³). The pH value of the samples varied between 3.3 and 4.6 with about 40% having pH lower than 3.7.     

传统泡菜的微生物学研究

从实验室自制的泡菜中分离出1株产酸快的乳酸菌菌株,对其形态特征、菌落特征、生理生化特性进行了鉴定,并以该菌株为纯发酵剂,在温度30℃条件下,分别以0％、5％、10％、15％、20％的接种量制备泡菜,7d后对自然发酵和人工发酵的泡菜进行品质对比,结果表明,人工接种发酵组的产酸速度和风味明显优于自然发酵组,为泡菜的工业化生产提供依据。     

Microbiological characteristics of Botillo, a Spanish traditional pork sausage

Counts of total aerobic mesophilic flora on Standard Plate Count (SPC) agar, lactic acid bacteria on de Man Rogosa Sharpe (MRS) agar, salt tolerant flora on SPC agar +7.5% NaCl, and Enterobacteriaceae on Violet Red Bile Glucose (VRBG) agar, and some physico-chemical parameters (Total solids and NaCl contents and pH and a_w values) were determined in 15 units of Botillo, a traditional dry-fermented sausage made in the NW of Spain.In general, high counts of all the investigated microbial groups were observed, with average values of 8.65 log Colony Forming Units (CFU)/g for the total aerobic mesophilic flora, 8.87 log CFU/g for the lactic acid bacteria, 6.56 log CFU/g for the salt tolerant flora, and 2.98 log CFU/g for the Enterobacteriaceae.After the end of the incubation period, from MRS agar, SPC agar +7.5% NaCl, and VRBG agar, 10 colonies were randomly taken from each Botillo unit and from each culture medium. A total of 150 strains per culture medium were then identified using classical methods.Among the isolates from MRS agar, Lactobacillus sakei predominated (23.3% of the isolates), followed by Lactobacillus alimentarius (17.3%), Lactobacillus curvatus (15.3%), Lactobacillus plantarum (12%) and Lactobacillus farciminis (10%). Of the 150 isolates obtained from SPC agar +7.5% NaCl, only 34 strains (22.6% of the isolates) belonged to the Staphylococcaceae or Micrococcaceae families. Among the Staphylococcaceae, Staphylococcus saprophyticus (8.6% of the isolates) was the main species, followed by Staphylococcus xylosus (4%), Staphylococcus lentus (2%) and Staphylococcus cohnii cohnii (1.3%); Staphylococcus epidermidis, Staphylococcus sciuri and Staphylococcus capitis were isolated in very low proportions. The Micrococcaceae strains isolated, belonging to the Micrococcus genus, could not be identified at species level. Of the 140 isolates obtained from VRBG agar, Hafnia alvei (32.14% of the isolates) was the main species, followed by Serratia liquefaciens (12.85%), Klebsiella oxytoca (5.71%) and Enterobacter cloacae (3.71%); only one isolate was identified as Salmonella (Salmonella arizonae) and one as Escherichia coli.     

Microbiological quality of rabbit meat

World rabbit meat production is estimated to be over 1 million tons, and Spain is the third largest producer. Although rabbit meat is marketed and consumed worldwide, information on microbiological quality is very scarce. Here, we report indicator organisms, spoilage flora, sensory quality, and some physicochemical traits of 24 h postmortem chilled rabbit carcasses and prepackaged rabbit meat stored chilled in air for 0 to 3 days at the retail level. The mean total bacterial count (4.01 +/- 0.48 log CFU/g) for carcasses dressed at a small abattoir by a manual process was significantly lower (P < 0.05) than that (4.96 +/- 0.90 log CFU/g) for carcasses dressed at a large abattoir in automated slaughter lines. Both groups of carcasses had mean pH values of 5.98. The dominant contaminants on carcasses from the small abattoir were Pseudomonas, lactic acid bacteria, and yeasts. These microorganisms and Brochothrix thermosphacta were dominant on carcasses from the large abattoir. On prepacked hind legs (pH 6.26 +/- 0.18) stored at -1 to +1 degree C (supermarket 1), mean aerobic mesophilic count was 5.87 +/- 1.03 log CFU/g, and the major microbial groups were Pseudomonas, yeasts, lactic acid bacteria, and B. thermosphacta. On prepacked whole carcasses (pH 6.37 +/- 0.18) displayed at -1 to +5 degrees C (supermarket 2), mean aerobic mesophilic count was 6.60 +/- 1.18 and the same microbial groups were dominant. Relative Escherichia coli incidence was supermarket 2 > large abattoir > supermarket 1 > small abattoir. Overall, low numbers of coliforms, Enterobacteriaceae, psychrotrophic clostridia, coagulase-positive staphylococci, and molds were found. Sensory scores, pH values, and L-lactic acid content differentiated fresh carcasses from retail samples. Data obtained suggest that the microflora of chilled rabbit meat are different from those found on the meat of other animals.     

Microbiological quality of Australian beef

A survey of the microbiological quality of beef carcasses and boneless beef produced in Australia was conducted during the period June to November 1998. Sponge samples were collected from 1,275 carcasses, and meat samples were drilled from 990 cartons of frozen boneless beef. Carcass and boneless beef samples were respectively collected from 21 and 27 establishments that concentrated on export and from 38 and 3 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering no more than 150 cattle equivalents per week. The mean log total viable counts (TVCs) were 2.42/cm2 and 2.52/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 10.3% of carcasses and 5.1% of boneless beef samples and coagulase-positive staphylococci on 24.3% of carcasses and 17.5% of boneless beef. Salmonella was detected on 0.2% of carcasses and 0.1% of boneless beef and E. coli O157:H7 recovered from 0.1% of carcasses but not detected on 990 boneless beef samples. Mean log TVCs/cm2 differed significantly (P < 0.05) between establishment types. They were lower on carcasses from export establishments (2.20) compared with domestic (2.61) and very small plants (3.10). There were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. Excision samples were taken from 670 carcasses to make comparisons with the first baseline study of Australian meat, carried out in 1993 to 1994. While there were differences in sampling and microbiological techniques between the two studies that require detailed consideration, there were small but significant improvements in several microbiological criteria for carcasses and boneless meat.     

Microbiological quality and safety of ready-to-eat street-vended foods in Johannesburg, South Africa

Fifty-one ready-to-eat street foods, 18 dishwater, and 18 surface swab samples were collected from six vendors in Johannesburg, South Africa. Food temperatures were recorded at the time of sampling. Standard methods were used to determine aerobic plate counts (APCs), spore counts (SCs), and Enterobacteriaceae counts (ECs) for food samples as well as coliform counts (CCs) for water and swab samples. In addition, Petrifilm Escherichia coli count (PC) plates were used for the enumeration of coliforms in food, water, and swab samples. The presence of selected foodborne pathogens in the food samples as well as the presence of nonpathogenic E. coli 1 (in food and water samples) was also tested for. Predominant colonies isolated from APC plates were characterized to the genus level. Holding temperatures for cooked meats and gravies ranged from 42.0 to 94.0 degrees C, and those for uncooked salads ranged from 29.0 to 39.0 degrees C. Mean APC values of 3.4 (+/-0.4) log CFU/g, 4.0 (+/-1.2) log CFU/ml, and 2.1 (+/-0.4) log CFU/25 cm2 were obtained for food, water, and swab samples, respectively. Mean SC values of 1.6 (+/-0.2) log CFU/g and 1.5 (+/-0.3) log CFU/25 cm2 were obtained for food and swab samples, respectively. A mean EC value of 2.0 (+/-0.4) log CFU/g for food samples and mean CC values of 2.5 (+/-0.3) log CFU/ml and 1.3 (+/-0.3) log CFU/25 cm2 for water and swab samples, respectively, were determined. Mean PC values of 1.6 (+/-0.1) log CFU/g, 1.9 (+/-0.6) log CFU/ml, and 1.4 (+/-0.4) log CFU/25 cm2 were determined for food, water, and swab samples, respectively. Bacillus cereus was detected in 22%, Clostridium perfringens in 16%, Salmonella spp. in 2%, and E. coli (non-O157:H+) in 2% of the 51 food samples. E. coli was found in 14 water samples (78%) and in 3 food samples (6%). Campylobacter spp., Listeria monocytogenes, Staphylococcus aureus, Vibrio cholerae, and Yersinia enterocolitica were also tested for in the food samples, but they were not detected. The 340 isolates obtained from APC plates for food, water, and swab samples were predominantly Bacillus spp., Micrococcus spp., and Staphylococcus spp. for all three sample types. It was concluded that the foods analyzed in this study were of acceptable quality and safety.     

冷冻饮品生产中几个应注意的问题

冷冻饮品已纳入国家QS认证范围,生产企业必须通过QS认证才能生产和销售。在冷冻饮品的生产中,对于不同规模、不同产品品种（冰淇淋、雪糕、雪泥、冰棍、食用冰、甜味水）以及相应的工艺来说,归根到底是生产中产品的质量安全问题,主要问题有：生产工艺条件、设备的保养、生产过程的清洗、消毒、产品的贮存等。     

Microbiological quality of artisanal Sepet cheese

Microbial diversity in milk and in cheese itself affects the biochemical and sensory characteristics of artisanal cheeses. In this study, the microflora of Sepet cheese, which is a traditional artisanal cheese in Turkey, was investigated. Average lactococci, lactobacilli, enterococci, yeast, mould, coliform, psychrotrophic and total aerobic bacteria, presumptive Staphylococcus aureus counts were; 7.31 ± 1.08, 7.19 ± 1.02, 6.84 ± 0.92, 3.19 ± 1.40, 0.84 ± 0.89, 2.18 ± 1.81, 4.92 ± 1.15, 7.53 ± 1.13 and 1.25 ± 1.70 log cfu/g, respectively. Staphylococci, coliform and mould counts were less than 1.00 log cfu/g at the end of ripening, which was at around 6–8 °C for 3 months. According to phenotypic and genotypic identifications, isolates were closely related to Lactobacillus plantarum, Weisella confusa, Weisella paramesenteroides, Pediococcus pentasaceous, Enterococcus casseliflavus, Enterococcus durans and Enterococcus faceium. This study provides baseline data on the microflora of traditional artisanal Sepet cheese, which is a prerequisite for a successful scale up to industrial production.     

Microbiological quality of fresh-cut sweet potatoes

Sweet potato roots were dipped in various concentrations of chlorine for 5 min at 1 or 20 °C before and after slicing, and then stored at 2 or 8 °C for 14 days to evaluate the effects of different chlorine treatments and storage temperatures on the microbiological quality of fresh‐cut sweet potato slices. The microflora of fresh‐cut sweet potato slices was dominated by mesophiles, followed by psychrotrophs and fungi initially and during storage. The 2 °C storage was necessary to keep the microbial load at a low level. No spoilage was observed in fresh‐cut sweet potatoes at both storage temperatures for 14 days. Chlorination of sweet potatoes before slicing was not effective in ensuring acceptable microbiological quality of fresh‐cut sweet potatoes. Dipping slices in 200 ppm chlorine at 1 °C reduced the population of all micro‐organisms during storage.     

茶饮料生产标准化与品质控制

报告了正在我国蓬勃发展的茶饮料产销态势、生产标准化与品质管理有关信息，并对品控技术的现状及发展趋势作一筒要分析，供有企业制订企业标准和组织实施现代管理参考，以使我国茶饮料加工产业能持续、健康、稳步发展。     

Microbiological quality of Australian sheep meat

Microbiological quality of sheep carcasses and boneless sheep meat produced in Australia was surveyed during the period June to November 1998. Sponge samples were collected from 917 carcasses, and meat samples were drilled from 467 cartons of frozen boneless meat. Carcass and boneless meat samples were respectively collected from 7 and 10 establishments that concentrated on export, and from 36 and 5 establishments supplying the Australian domestic market of which 31 were very small plants slaughtering cattle and sheep but no more than 1,200 sheep equivalents per week. The mean log total viable counts were 3.55/cm2 and 3.30/g for carcasses and boneless meat, respectively. Escherichia coli was detected on 29.2% of carcasses and 24.5% of boneless meat samples and coagulase-positive staphylococci on 24.1% of carcasses, and 38.6% of boneless meat samples. Salmonella was detected on 0.1% of carcasses and 1.3% of boneless meat samples. E. coli O157:H7 was recovered from 0.7% of carcasses and 1.3% of boneless sheep meat. There were statistically significant differences between establishment types for some microbiological criteria, although there were no significant differences in prevalence of Salmonella or E. coli O157:H7 between establishment types. While there were differences in sampling and microbiological techniques between this study and another conducted in 1993 to 1994 that require detailed consideration, there were small but significant improvements in several microbiological criteria for boneless meat. While data that would allow for comparison of carcass data were not gathered, it is unlikely that improvements in the microbiological quality of boneless sheep meat could accrue without improvements to carcasses.     

Microbiological quality of frozen raw and cooked shrimps

The microbiological quality of frozen raw and cooked shrimps destined for import and export was determined. The total number of frozen shrimp samples tested were 657 comprising 54 (FW) freshwater shell-on, 29 freshwater peeled deveined, 123 seawater (SW) shell-on, 410 seawater peeled deveined, and 41 seawater cooked. The geometric means for APC g⁻¹, coliform counts (MPN g⁻¹) and E. coli counts (MPN g⁻¹) were, respectively, FW shell-on, 890 000, 82 and 14; FW peeled deveined, 430 000, 16 and 5; SW shell-on, 310 000, 10 and 3; SW peeled deveined, 410 000, 9 and 3 and seawater cooked 7000, 4 and 3. 653 (99%) of the samples had S. aureus counts of less than 50 MPN g⁻¹. Shigella and Vibrio cholerae were not detected and Salmonella was positive for 3 (0·5%) of the 657 samples tested.     

影响果汁饮料质量的关键技术

果汁饮料因其营养丰富及饮用方便而受到很多人的追捧,成为消费时尚。然而我国果汁加工业还没有一个比较完善的通用加工流程,很多问题仍然得不到合理的解决。介绍了影响果汁饮料质量的几个关键技术,以期带动行业发展。     

Microbiological quality of Australian sheep meat in 2004

The third national baseline microbiological survey of Australian sheep carcases and frozen boneless sheep meat was conducted in 2004. Carcases (n=1117) sampled at 20 slaughter establishments were found to have a mean log total viable count (TVC, 25°C) of 2.28 cfu/cm(2) and Escherichia coli was isolated from 43.0% carcases with a mean log 0.03cfu/cm(2) on positive samples. In samples from 10 boning (fabrication) plants (n=560) the mean log TVC for frozen boneless sheep meat was 1.85cfu/g and the mean log count for the 8.2% of samples with detectable E. coli was 1.39cfu/g. E. coli O157:H7 was isolated from 6/1117 carcases and from 1/560 boneless samples. Salmonella was isolated from 0/1117 carcases and from 3/560 samples of boneless product. Campylobacter sp. were isolated from 4/1117 carcases and from 1/560 boneless samples. Coagulase positive staphylococci were isolated from 23.4% to 32.7% of carcases and boneless sheep meat samples, respectively, with positive samples having a mean log count of 0.93cfu/cm(2) and 1.14cfu/g, respectively. The low level of bacteria described here is consistent with a very low risk to human health due to bacterial hazards in Australian sheep meat.     

Microbiological quality of retail chicken by-products in Spain

The microbiological quality of retail chicken parts (legs, wings and giblets) and processed chicken products (hamburgers and sausages) in Spain was investigated. Mean counts (log(10) cfu/g) ranged from 5.56 to 7.28, 5.96 to 7.87, 3.49 to 5.42, 2.60 to 4.33 and 2.47 to 3.48 for mesophiles, psychrotrophs, coliforms, Escherichia coli and Staphylococcus aureus, respectively. Chicken parts were generally regarded as being of unacceptable quality, since psychrotrophs, E. coli and S. aureus counts were higher than the maximum limits established in the guidelines for poultry meat. On the basis of Spanish Microbiological Standards, 80% of the samples of hamburgers and sausages were also regarded as being of unacceptable quality. The main reason for the lack of acceptability was excessive counts of mesophiles. The results in this study indicate that chicken by-products (especially those made with ground meat) could represent notable hazards to humans and are a cause of public health concern.     

Microbiological quality of some retail spices in India

A total of 154 samples of 27 kinds of spices from retail shops of 20 States of India was investigated to determine their microbial status. As per ICMSF specifications, the total aerobic mesophilic bacteria (TAMB) count showed that 51% of the samples were in the unacceptable level (>10⁶ cfu g⁻¹). While moulds were detected in 97% of the samples, yeast was found in only one. Bacillus cereus, Clostridium perfringens, Staphylococcus aureus and members of Enterobacteriaceae occurred in 85, 59, 11 and 85%, respectively of the kinds. Whereas black pepper powder, caraway, garlic and red chilli did not contain B. cereus, this foodborne pathogen was found in all the samples of ajmud, small cardamom and cumin powder. Coliforms and faecal coliforms were found in 33 and 15%, respectively of the kinds. Escherichia coli was detected in only one sample, of garlic. Salmonella and Shigella were found only in 2.6% of the samples. Although they contained less TAMB, the non-packaged spices had a higher load of moulds, B. cereus and Enterobacteriaceae than that of polyethylene-packaged ones.     

Microbiological quality of freshly shot game in Germany

In the framework of a project on the hygiene status of freshly shot game 289 samples were microbiologically analysed: 127 samples from wild boars, 95 from roe deer and 67 from red deer. The microbiological parameters evaluated were the mesophilic aerobic count (APC), which showed mean log10-counts of 2.6 cfu/cm² for roe deer, 2.9 cfu/cm² for red deer and 3.2 cfu/cm² for wild boars and the numbers of Enterobacteriaceae, which gave mean log10-values of 2.1 cfu/cm² for all three species with differing ranges. The concentrations of coagulase positive staphylococci were >2.0 log10 cfu/cm² between 3.2 and 6.3%, according to species. Listeria was found in 14 samples and three samples gave a positive result for Campylobacter. Salmonella was not found in any of the samples analysed.