A bacteriological study of some frozen and nonfrozen foods.

Over a period of 19 months, a total of 331 food samples were submitted to the Food Section of the Bacteriology Division for bacteriological examination. These included 184 samples of frozen seafoods from exporters and 147 samples of fresh, nonfrozen foods from food caterers. The total bacterial count for frozen seafoods ranged from 1 x 10(2) to 2.98 x 10(6) per gm with a mean of 2.14 x 10(5) per gm. Coliforms, Escherichia coli and Staphylococcus aureus were present in 48.9%, 3.3% and 8.2% of the samples examined respectively. Two of the cooked prawn samples showed the presence of Vibrio parahaemolyticus. For the fresh, nonfrozen foods, the total bacterial count ranged from 1 x 10(2) to 3.87 x 10(6) per gm with a mean of 2.58 x 10(5) per gm. The examination also showed that 74.8% were coliform positive, 14.9% were E. coli positive, and 4.8% were S. aureus positive. V. parahaemolyticus was not isolated in any of the samples tested. Other pathogens, namely, Vibrio cholerae, Salmonella and Shigella were not isolated from any of the foods examined. The bacterial levels in these foods were determined and their sanitary and public health significance is discussed.     

浙江省副溶血性弧菌污染水平及贝类海产品风险评估

摘要 ：目的 在研究浙江省各类食品中副溶血性弧菌污染水平的基础上,进行贝类海产品副溶血性弧菌感染风险评估。方法 对2215件市售食品用科玛嘉弧菌显色培养基分离副溶血性弧菌,并用API 20E鉴定条鉴定;用Ross Ranger-Sumner软件进行贝类海产品副溶血性弧菌感染风险评估;用PCR方法进行毒力基因检测。结果 副溶血性弧菌检出率鲜(活)海水产品为43.06 %、生/半生食海产品为32.52 %、鲜活淡水产品为22.22 %、生畜肉为13.52 %、生禽肉为11.44 %、散装熟肉制品为3.44 %、中式凉拌菜为2.98 %、生食蔬菜为2.10 %、鲜奶蛋糕为2.08 %。8月-10月副溶血性弧菌检出率显著高于4月～6月（P=0<0.01,x2=46.445）。农贸市场采集的食品副溶血性弧菌检出率显著高于超市（P=0.001<0.01,x2=10.252）。tdh毒力基因携带率为3.66 %（3／82）,trh基因全部阴性。生食或半生食牡蛎等贝类海产品副溶血性弧菌感染风险系数分别为50（生食）和48（半生食）,每年因食用牡蛎等贝类海产品导致副溶血性弧菌食源性疾病的人数为4.42×104人（生食）和2.21×104人（半生食）,如果烹饪彻底,风险系数降可至零。结论 浙江省各类食品中副溶血性弧菌污染问题突出,防止食品间交叉污染,不生食半生食海水产品,即食食品食用前加热处理是减少副溶血性弧菌食源性疾病发生的最有效方法。     

2012年甘肃省平凉市食源性致病菌污染监测结果分析

目的了解甘肃省平凉市食品中食源性致病菌污染状况,为预防控制食源性疾病提供科学依据。方法在选定的监测点和采样场所定期随机采样,按样品原有储存温度要求在最短时间内送实验室,按《2012年食源性致病菌监测工作手册》和中华人民共和国国家标准《食品卫生微生物学检验》(GB/T4789-2003)规定的程序和方法检测分离致病菌。结果全年共采集405份样品,从15份样品中检出致病菌,总检出率为3.70%;阪崎杆菌检出率最高为17.78%,七大类食品中婴幼儿食品污染最为严重、阳性率17.78%,街头食品中检出率最高为25.00%;中型餐馆、快餐店和集体食堂采集的食品中未检出;散装食品中检出率为1.97%,定型包装食品中检出率为16.00%。结论甘肃省平凉市市售食品存在食源性致病菌污染现象,婴幼儿食品中以阪崎肠杆菌污染为主,街头食品中食源性致病菌检出率最高。     

Parasitic contaminants in food

There is a wide variety of food products that may be contaminated with one or more parasites and consequently enabling transmission to human beings. The prevalence of specific parasites in food supplies varies between countries and regions. Sources of food-borne products contaminated with parasites are pigs, cattle, fish, crabs, crayfish, snails, frogs, snakes and aquatic plants. One of the major factors influencing the prevalence of parasitic infections in the population is the habit, and traditional popularity of eating raw or inadequately cooked foods. The parasites that may be acquired by eating these foods are nematodes, trematodes, cestodes and protozoa. The major genera of parasites are Trichinella, Gnathostoma, Angiostrongylus, Anisakis, Paragonimus, Clonorchis, Opisthorchis, Fasciola, Fasciolopsis, Echinostoma, Taenia, Spirometra and Toxoplasma. These food-borne parasitic infections are public health problems worldwide. The contamination of food affects many including humans, livestock industry, agriculture, and food manufacturing and processing. Unsafe foods must be condemned and destroyed. Today there is increasing travel hence there is the risk of humans' acquiring food-borne parasitic infections through eating native food often raw. Moreover, the consumption of imported livestock and foods, especially from endemic areas of food-borne parasitic zoonoses, can be the cause of infection. Awareness should be heightened wherever and whenever raw or inadequately cooked food are consumed.     

Detection of tdh and trh genes in Vibrio parahaemolyticus isolated from Corbicula moltkiana prime in West Sumatera, Indonesia

The occurrence of Vibrio parahaemolyticus in raw Corbicula moltkiana Prime from Lake Singkarak and Pasar Raya Padang market and in cooked samples in West Sumatera, Indonesia, was studied. Thirteen raw and seven cooked bivalve samples were positive using CHROMAgar Vibrio medium. All 47 V parahaemolyticus isolates were positive for toxR gene but negative for trh. However, 36% (17/47) of V parahaemolyticus strains were positive for tdh gene. Antibiotic profiling showed that 76% and 38% of isolates from raw and cooked bivalves respectively were resistant to ampicillin. Using RAPD-PCR analysis, most of the strains were clustered according to their source of isolation but some of the strains from raw and cooked samples were clustered together. These results indicate that pathogenic V parahaemolyticus isolates are present in Corbicula moltkiana Prime in West Sumatera, Indonesia, suggesting that V parahaemolyticus may also be present in seafood in other regions of Indonesia.     

Research note: Molecular subtyping of Salmonella enterica serovar Tshiongwe recently isolated in Malaysia during 2001-2002

Pulsed field gel electrophoresis (PFGE) and antimicrobial susceptibility analysis were undertaken on twenty-three strains of Salmonella enterica serovar Tshiongwe, an unusual serovar, which recently emerged in Malaysia. Antimicrobial susceptibility analysis showed that all the strains were sensitive to ampicilin, chloramphenicol, cotrimoxazole, and kanamycin. Twenty (87%) and 8 (3.5%) strains had resistance to tetracycline and streptomycin respectively. PFGE analysis subtyped 23 strains into 10 profiles (Dice coefficient of similarity, F = 0.7-1.0). The predominant profile, X1 was found in both clinical and environmental isolates and was widely distributed in different parts of Malaysia during the study period. In addition, isolates recovered from food, a hand-towel, apron and the surface of a table-top in one particular location had unique, indistinguishable profiles (X4/4a) and identical antibiograms. Similarly, isolates from cooked meat and a chopping board had PFGE profiles similar to some human isolates. These probably indicated cross-contamination and poor hygiene in food practices, hence contributing to Salmonellosis. Factors causing the emergence of this rare Salmonella serovar being responsible for food poisoning episodes during the study period remained unclear. The study reiterated the usefulness and versatility of PFGE in the molecular subtyping of this rare Salmonella serovar in Malaysia.     

市售熟食单核细胞增生李斯特菌流行病学分析

目的了解市售散装熟食中Lm污染状况，探索Lm在熟食中流行特征。确定控制Lm的关键控制点。方法采集市售熟食、宾馆饭店熟食、生产熟食用原料、生产场所环境及用具、熟食销售场所环境及用具、宾馆饭店熟食间环境及用具样品共883份检测Lm，用统计学处理分析结果。结果市售散装熟食Lm检出率为13．06％，宾馆饭店熟食Lm检出率为1．02％。二者间有极显著差异（P〈0．01）。生产原料Lm检出率为3．00％．生产环境及用具Lm检出率为22．22％。销售环境及用具Lm检出率11．02％，宾馆饭店熟食间环境及用具未检出Lm。二者间有显著差异（P〈0．05）。结论市售熟食Lm与宾馆饭店熟食有极显著差异；销售环境及用具Lm与宾馆饭店熟食间环境及用具有显著差异。Lm关键控制点：建立相对封闭的销售环境。加强熟食冰箱、柜台内外、销售用具的消毒措施。     

Prevalence of Vibrio parahaemolyticus in seafood from restaurants in the city of Mérida, Yucatán

We report the prevalence of the Vibrio parahaemolyticus in raw (11.54%), insufficiently cooked (0.00%) and partially cooked with heat (4.55%) sea foods, from restaurants of the city of Merida, Yucatan, Mexico. We studied 190 samples from March to August 1987. We isolated 12 strains (6.32%) from an equal number of samples, whose biochemical characteristics corresponded with Vibrio parahaemolyticus. We didn't find significant statistically differences when we compared the prevalences of the samples of raw and insufficiently cooked sea foods (chi 2 = 0.03, p greater than 0.05), of raw and partially cooked with boiled sea foods (chi 2 = 1.96, p greater than 0.05), and of insufficiently heated and partially cooked with heat sea foods (chi 2 = 0.24, p greater than 0.05). When we compared the prevalences of the samples of crustaceans and mollusks, of crustaceans and fishes, and of mollusks and fishes, we didn't find significant statistically differences: chi 2 = 0.022, p greater than 0.05; chi 2 = 0.52, p greater than 0.05 and chi 2 = 1.78, p greater than 0.05, respectively.     

Emergence of Salmonella enteritidis phage type 4 in the Caribbean: case-control study in Trinidad and Tobago, West Indies.

A prospective case-control study involving 46 case patients and 92 age- and neighborhood-matched control subjects was conducted in Trinidad and Tobago (T&T) between March 1998 and May 1999 to determine the etiology, sources, and risk factors for Salmonella enteritidis (SE) infection. SE infection in T&T was found to be associated with the consumption of shell eggs, and in particular raw or undercooked eggs. SE isolates from 30 (88%) of 34 patients and from 9 implicated egg or egg-containing food samples were phage type 4. Homemade eggnog and ice cream, cake batter, and egg-containing beverages were the main raw egg-containing foods, reflecting the cultural practices of the people of T&T. Public health education on the risks of eating raw or undercooked eggs, thorough cooking of all egg dishes, and refrigeration of shell eggs and egg dishes; studies tracing infected eggs to their sources; and testing of flocks of layer chickens for SE are needed to reduce the incidence of this infection.     

Effect of Modifying the Rate of Digestion of a Food on the Blood Glucose, Amino Acid, and Endocrine Responses in Patients with Cirrhosis

To see whether foods with slower rates of digestion may benefit the metabolic abnormalities seen in cirrhosis, the same food, processed in two different ways, was fed to seven patients with cirrhosis. The breakfast of lentils processed by prolonged heating, to produce more rapid in vitro digestion, resulted in a significantly higher incremental rise in large neutral amino acid levels at 60 min (p less than 0.02) and a tendency for a more rapid rise in total amino acid concentrations by comparison with conventionally cooked lentils with slower in vitro digestion rates. After more rapidly digested lentils, incremental levels of branched-chain amino acids were also higher at 60 min (67 +/- 9, p less than 0.001) despite a greater overall insulin response. Comparable incremental amino acid areas after both meals suggested that the total amount of amino acids absorbed was not influenced by processing. Greater blood glucose, insulin, and gastric inhibitory polypeptide responses were seen after the more processed meal with no significant differences in pancreatic glucagon, entroglucagon, or neurotensin levels. Processing a food to alter the rate of digestion may therefore be used to manipulate amino acid, glucose, and endocrine responses in cirrhosis.     

Fecal solids excreted by young men following the ingestion of dairy foods

Summary The amounts of intestinal residue excreted by healthy human subjects following the ingestion of a low-residue intake alone and in the presence of a dairy food, or a combination of dairy foods, have been determined. Sweet milk, buttermilk, Cheddar cheese, and a combination of sweet milk, Cheddar cheese, and vanilla ice cream were fed at three levels of intake.Among the periods when a dairy food was fed, total fecal solids were highest during the sweet-milk period, 20.7–25.5 gm., and lowest during the cheese and combination periods, 18.0–21.2 gm. compared to 14.8–16.1 gm. fecal solids on the low residue diet. Buttermilk induced less increase in total fecal solids (21.4–23.7 gm.) than did sweetmilk, but more than Cheddar cheese (18.0–20.8 gm.) or the combination of dairy foods (18.5–21.2 gm.). It is significant that sweetmilk fed in combination with Cheddar cheese and vanilla ice cream induced proportionately less increase in intestinal residue than sweetmilk fed alone.This investigation was supported by a grant from the National Dairy Council. Chicago. Ill.     

ANTIMICROBIAL DRUG RESISTANCE IN STRAINS OF Escherichia coli ISOLATED FROM FOOD SOURCES

A variety of foods and environmental sources harbor bacteria that are resistant to one or more antimicrobial drugs used in medicine and agriculture. Antibiotic resistance in Escherichia coli is of particular concern because it is the most common Gram-negative pathogen in humans. Hence this study was conducted to determine the antibiotic sensitivity pattern of E. coli isolated from different types of food items collected randomly from twelve localities of Hyderabad, India. A total of 150 samples comprising; vegetable salad, raw egg-surface, raw chicken, unpasteurized milk, and raw meat were processed microbiologically to isolate E. coli and to study their antibiotic susceptibility pattern by the Kirby-Bauer method. The highest percentages of drug resistance in isolates of E. coli were detected from raw chicken (23.3%) followed by vegetable salad (20%), raw meat (13.3%), raw egg-surface (10%) and unpasteurized milk (6.7%). The overall incidence of drug resistant E. coli was 14.7%. A total of six (4%) Extended Spectrum β-Lactamase (ESBL) producers were detected, two each from vegetable salads and raw chicken, and one each from raw egg-surface and raw meat. Multidrug resistant strains of E. coli are a matter of concern as resistance genes are easily transferable to other strains. Pathogen cycling through food is very common and might pose a potential health risk to the consumer. Therefore, in order to avoid this, good hygienic practices are necessary in the abattoirs to prevent contamination of cattle and poultry products with intestinal content as well as forbidding the use of untreated sewage in irrigating vegetables.     

云南省旋毛虫病家庭聚集性分析

目的 了解云南省旋毛虫病家庭聚集性，为健康促进和干预活动提供信息。方法采用二项分布拟合原理对生吃或半生吃猪肉、砧板生、熟食混用等与健康有关的生活行为和习惯及旋毛虫血清学阳性进行家庭聚集性分析。结果 旋毛虫血清学阳性、生吃或半生吃猪肉、砧板生、熟食混用行为习惯分别占调查人数的8．1％、13．8％、24．1％，其分布均存在显著的家庭聚集性（P均〈O．05）。结论 云南省人群旋毛虫感染呈家庭聚集性，可能与相关健康行为的家庭聚集性有关。     

Potential sources of Campylobacter species in the homes of farmworkers in Zimbabwe.

Chicken faeces, houseflies, household stored drinking water, cooked or prepared foods and handwashings of people of all age groups and hands of children under 5 years old were examined as potential sources and transmission routes of Campylobacter species in a farmworker community. Campylobacter species were found to be common in chicken faeces collected from the homesteads of the farmworkers but were rarely isolated from houseflies or household stored drinking water. They were not isolated from foods and hands of people of all ages. A comparison of Campylobacter species isolated from humans and chickens showed Campylobacter jejuni to be more common than Campylobacter coli in human isolates while the two species were evenly distributed in chickens. Most of the C. jejuni isolates from humans and chickens belonged to biotype II and none belonged to biotype III. There was some similarity in some C. jejuni serotypes isolated from humans and chickens. Chickens were therefore found to be the main potential source of Campylobacter species in the homes of farmworkers.     

Surveys on the contamination of marine fish with non-O1 Vibrio cholerae and Vibrio mimicus and food poisoning cases by these organisms

The present paper describes the relationship between the contamination with non-O1 Vibrio cholerae and Vibrio mimicus of marine fish, with special reference to the seasonal variation and the concentration of contamination, and the actual cases of domestic food poisoning by these organisms. A 10 year survey revealed that non-O1 Vibrio cholerae (non-O1 V. cholerae) strains were frequently isolated from fish during the summer season with some variations from one year to another, and isolates from fish showed similar biological properties to those of isolates from diarrhea cases of over-sea travellers. Experimentally enteropathogenic strains were included among these isolates. Vibrio mimicus (V. mimicus) strains were also isolated from fish, the frequency being not so high as in the case of non-O1 V. cholerae Strains of serovar O-41 which was most predominant among strains from diarrhea cases were also detected among the isolates from fish. The viable cell counts, however, were very small with regard to both non-O1 V. cholerae and V. mimicus From these observations, factors causing food poisoning by non-O1 V. cholerae or V. mimicus seemed to be essentially similar to those by Vibrio parahaemolyticus (V. parahaemolyticus); that is, the food poisoning by non-O1 V. cholerae or V. mimicus is apt to occur in the summer season and is caused by the consumption of raw fish, although the frequency might be significantly low in comparison to that of V. parahaemolyticus. The actual cases of the domestic food poisoning by non-O1 V. cholerae or V. mimicus were retrospectively surveyed by the literature.(ABSTRACT TRUNCATED AT 250 WORDS)     

Molecular epidemiology of Salmonella Enteritidis food poisoning by pulsed-field gel electrophoresis

During the years 1983 to 1999, a total of 120 Salmonella Enteritidis (SE) isolates from various sources, patient's stool, foods, kitchen wear, river water etc., in 61 cases of food poisoning in the Sakai City, were typed by pulsed-field gel electrophoresis (PFGE) after XbaI or NotI digestion of chromosomal DNA. XbaI and NotI restriction produced 2 (X1 and X2) and 3 (N1, N2 and N3) pulse-field profiles, respectively. The X1 and N1 types were further divided into 8 (Xla-Xlh) and 6 (N1a-N1f) subtypes, respectively. However, these strains of subtypes showed only 0-4 fragment changes in PFGE patterns and the index of discrimination of over 0.75, indicating that SE isolates belong to the same clonal lineage, or are revealing closely clonal relationships. These results suggested a possible strain transmission in case of food poisoning, and epidemiologically related SE isolates were spread in the Sakai City district during a long period.     

Detection of Vibrio parahaemolyticus and Vibrio cholerae in oyster, Crassostrea rhizophorae, collected from a natural nursery in the Cocó river estuary, Fortaleza, Ceará, Brazil

Oysters are edible organisms that are often ingested partially cooked or even raw, presenting therefore a very high risk to the consumers' health, especially in tropical regions. The presence of Vibrio cholerae and Vibrio parahaemolyticus in oysters sampled at an estuary in the Brazilian northeastern region was studied, with 300 oysters tested through an 8-months period. The salinity of the water at the sampling point varied between 3% and 27. V. cholerae was the most frequently detected species (33.3% of the samples), and of the 22 V. cholerae isolates, 20 were identified as non-O1/non-O139, with two of the colonies presenting a rough surface and most of remaining ones belonging to the Heiberg II fermentation group. V. parahaemolyticus was isolated from just one of the samples. Other bacteria such as Providencia spp., Klebsiella spp. and Morganella morganii were also isolated.     

An outbreak of food-borne Campylobacter jejuni infection and the possible role of cross-contamination

A point-source outbreak or campylobacter infection affected 24 of 51 delegates attending a business lunch. Failure to detect any specific vehicle for the infection led to observations of kitchen practice. Experiments demonstrated that cross-contamination as a result of handling raw and cooked food consecutively was a possible cause of the outbreak.     

Isolation of Shiga toxin-producing Escherichia coli O157:H7 from processed salmon roe associated with the outbreaks in Japan, 1998, and a molecular typing of the isolates by pulsed-field gel electrophoresis

Shiga toxin-producing Escherichia coil (STEC) O157 were isolated from processed salmon roe which had been a suspected food item in sporadic infections which occurred in Japan in 1998. A total of 45 samples of the processed salmon roe were pre-enriched in trypticase soy broth (TSB) at 36 degrees C for 6 h and novobiocin-supplemented modified EC broth (mEC-NB) at 42 degrees C for 18 h. After the pre-enrichments, the cultures were examined for possible occurrence of STEC O157, using an immunomagnetic separation (IMS) method. From the examination, a total of 84 strains of STEC O157:H7 that were positive for both stx 1 and stx 2 genes were isolated. By applying the most-probable-number technique, it was estimated that the number of STEC O157 was in the range of 0.73-1.5 per 10 g of the processed salmon roe. Subsequent analysis of the isolates by a pulsed-field gel electrophoresis (PFGE) revealed a pattern commonly seen in 82 isolates and another pattern in two isolates. Clinical isolates from 7 patients also showed an identical pattern to those of the 82 isolates and one isolate from a patient showed the other pattern identical to those of the two isolates. The isolates were found to belong to the phage type 14.     

Raw fish consumption in liver fluke endemic areas in rural southern Laos

Consumption of raw or insufficiently cooked fish is a major public health concern in Southeast Asia, and in Lao People's Democratic Republic (Lao PDR), in particular. We aimed to assess the knowledge, attitudes, perceptions and practices of villagers in liver fluke endemic areas related to raw fish preparation, consumption and its health consequences. In February 2010, eight focus group discussions (FGDs, 35 men and 37 women total) and direct observations were conducted in four randomly selected villages in Saravane District, Saravane Province (Lao PDR). FGDs distilled the knowledge, attitudes, perceptions and practices of adult community members on raw fish preparation, consumption and its consequences for health. Conversations were transcribed from notes and tape-recorders. MaxQDA software was used for content analysis. Knowledge regarding the health effects of raw fish consumption was heterogeneous. Some participants did not associate liver fluke infection with any ill health, while others linked it to digestive problems. Participants also associated vegetables and tree leave consumption with liver fluke infection. The majority of FGD participants considered fish flesh that had been prepared with weaver ant extract to be safe for consumption. Visual appearance, taste, smell and personal preference were given as reasons for consuming raw fish dishes. Moreover, participants considered it a traditional way of food preparation, practiced for generations in Laos. Ten different fish dishes that use raw or fermented fish were identified. All FGD participants reported consuming dishes with raw fish. This study reveals a low degree of knowledge among local people on the health risks related to frequent consumption of raw or insufficiently cooked fish. Fish dishes were considered to be ‘well-prepared’ (that is, ‘cooked’) even though the fish had not been heated. In future, successful health education campaigns will have to address the specific knowledge, attitudes, perceptions and practices of the concerned population.