Production of Staphylococcus aureus Enterotoxin A in Raw Milk at High Temperatures

2014 ◽  
Vol 77 (9) ◽  
pp. 1612-1616 ◽  
Author(s):  
I. I. SABIKE ◽  
H. FUJIKAWA ◽  
M. Z. SAKHA ◽  
A. M. EDRIS
Keyword(s):  
Staphylococcus Aureus ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Food Poisoning ◽  
Raw Milk ◽  
The Other ◽  
Milk Samples ◽  
Natural Microflora ◽  
Processing And Storage ◽  
And Storage

Improper processing and storage of raw milk contaminated with Staphylococcus aureus at elevated temperatures can result in the production of staphylococcal enterotoxins, especially type A (SEA), which is most frequently associated with food poisoning outbreaks such as the large one in Osaka, Japan, in 2000. In this study, the characteristics of S. aureus growth and SEA production at various high temperatures in raw milk samples were studied using two raw milk samples naturally containing low and high levels of natural microflora. The optimal temperatures found for SEA production in the two milk types were as high as 40 and 44°C (range, 36 to 48°C), and SEA production was dependent on the initial dose of S. aureus. These high temperatures were close to that of the outbreak in Japan. Thus, it was concluded that temperature was critical for SEA production in raw milk. It was also observed that natural microflora in the milk samples considerably suppressed SEA production but not staphylococcal growth. On the other hand, the amount of toxin in most milk samples decreased after peaking during storage.

scholarly journals Staphylococcus aureus growth and enterotoxin production in different types of milk

2012 ◽  
Vol 60 (5) ◽  
pp. 103-108 ◽  
Author(s):  
Bohdana Janštová ◽  
L. Necidová ◽  
B. Janštová ◽  
L. Vorlová
Keyword(s):  
Staphylococcus Aureus ◽  
Storage Temperature ◽  
Raw Milk ◽  
Storage Conditions ◽  
Growth Patterns ◽  
Significant Finding ◽  
Uht Milk ◽  
Staphylococcal Enterotoxins ◽  
Natural Microflora ◽  
And Storage

The aim of our study was to assess Staphylococcus aureus growth and the time of first detection of staphylococcal enterotoxins type A, B and C (SEA, SEB, SEC) in different type of milk, depending on the strain and storage conditions. Raw, pasteurized, and UHT milk were inoculated with three strains of S. aureus, and growth patterns were determined by the plate method in accordance with EN ISO 6888-1. Baird-Parker agar medium was used for the detection of S. aureus and the Enzyme Linked Fluorescent Assay (ELFA) used with a miniVIDAS analyzer tested the production of staphylococcal enterotoxins. The results of model experiments showed the dependence of the growth rate and subsequent production of staphylococcal enterotoxins on incubation (storage) temperature, S. aureus strain, and type of milk. A significant finding was that the growth of S. aureus and production of enterotoxins in raw milk was inhibited by natural microflora, and production of enterotoxins was therefore not detected in raw milk within 102 hours of storage either at 15 °C or 22 °C. The highest risk of SEs production is associated with secondary contamination of pasteurized and UHT milk when stored at room temperature, where production was first detected after 12 hours of incubation.

Occurrence of Enterotoxic Staphylococcus aureus in Raw Milk from Yaks and Cattle in Mongolia

2007 ◽  
Vol 70 (7) ◽  
pp. 1726-1729 ◽  
Author(s):  
URANCHIMEG TSEGMED ◽  
GIOVANNI NORMANNO ◽  
MARIT PRINGLE ◽  
KAREL KROVACEK
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Products ◽  
Food Poisoning ◽  
Raw Milk ◽  
Latex Agglutination ◽  
Animal Origin ◽  
Foodborne Illnesses ◽  
First Report ◽  
Milk Samples ◽  
Milk And Dairy Products

Staphylococcal food poisoning is considered one of the leading foodborne illnesses in humans worldwide and is associated with contaminated foods of animal origin, such as milk and dairy products. In this study, we investigated the occurrence of staphylococci and the enterotoxigenic properties of Staphylococcus aureus isolated from raw milk from yaks (Bos mutus) and cattle in Mongolia. Staphylococci were isolated from 72 (74%) of the 97 raw milk samples. Of the samples containing staphylococci, 69% (50 of 72) were from yaks and 30.5% (22 of 72) were from cattle. S. aureus was detected in 10% of yak (7 of 72) and 21% of cattle (15 of 72) milk samples. Staphylococcal enterotoxin C was detected in 23% (5 of 22) of the S. aureus strains investigated, based on the reverse passive latex agglutination technique. Three of the five enterotoxigenic strains were from yaks and two were from cattle. None of the S. aureus strains tested produced staphylococcal enterotoxins A, B, or D. To our knowledge, this is the first report of the occurrence of staphylococci and enterotoxigenic S. aureus in milk from yaks and cattle in Mongolia.

scholarly journals Prevalence and Characteristics of Staphylococcus aureus Isolated From Retail Raw Milk in Northern Xinjiang, China

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaomeng Kou ◽  
Huixue Cai ◽  
Shudi Huang ◽  
Yongqing Ni ◽  
Baolong Luo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Virulence Gene ◽  
Raw Milk ◽  
Resistance Rate ◽  
Control Measures ◽  
Cow Milk ◽  
Distribution Area ◽  
Northern Xinjiang ◽  
Milk Samples

Staphylococcus aureus is one of the main pathogens causing mastitis in dairy animals worldwide. It is an important opportunistic pathogen of raw milk, and the enterotoxin causes significant food poisoning. Monitoring the antibiotic resistance of S. aureus in raw milk is helpful for a risk assessment of S. aureus. In this study, 62 strains (43.1%) of S. aureus were isolated from 144 retail raw milk samples of different varieties from four regions in northern Xinjiang, China. Among them, the isolation rates at Shihezi, Hami, Altay, and Tacheng were 58.1% (54/93), 12.9% (4/31), 18.2% (2/11), and 22.2% (2/9), respectively. The isolation rate of positive strains in cow milk samples was the highest (61.7%, 37/60), followed by camel milk (35.9%, 23/64), and horse milk (10.0%, 2/20). The results of the classical virulence genes test showed that 12.9% (8/62) of the isolates carried at least one virulence gene. The main genotype was see (6.5%, 4/62), followed by sea+sec (3.2%, 2/62), sea (1.6%, 1/62), and sec (1.6%, 1/62). The analysis of 13 resistance genes and the susceptibility to 12 different antibiotics of 62 isolates showed that 80.6% (50/62) of the strains were resistant to at least one antibiotic, and 46.8% (29/62) were resistant to three or more antibiotics. The isolated strains had the highest resistance rate to penicillin (72.6%, 45/62), and 25.8% (16/62) of the isolates carried the blaZ resistance gene. In addition, 32 strains (51.6%, 32/62) of methicillin-resistant S. aureus were detected. All isolates had the ability to form biofilms. The pulsed-field gel electrophoresis results showed that the 47 isolates revealed 13 major pulsotypes (P1–P13) and 26 subtypes with 80% similarity, indicating the overall genetic diversity in the distribution area and sources of the samples. These findings indicate that S. aureus causes serious pollution of raw milk in northern Xinjiang, which has a negative effect on public health. Therefore, control measures and continuous monitoring should be undertaken to ensure the quality and safety of raw milk.

Phylogeny Characterization of Seb Gene Encoding Enterotoxins in Staphylococcus aureus Isolated from Raw Milk and Cheese

2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
Fatima N. Aziz ◽  
Laith Abdul Hassan Mohammed-Jawad
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Raw Milk ◽  
Staphylococcal Enterotoxin B ◽  
Human Pathogen ◽  
Conventional Pcr ◽  
Biochemical Tests ◽  
Specific Primers ◽  
Gene Encoding

Food poisoning due to the bacteria is a big global problem in economically and human's health. This problem refers to an illness which is due to infection or the toxin exists in nature and the food that use. Milk is considered a nutritious food because it contains proteins and vitamins. The aim of this study is to detect and phylogeny characterization of staphylococcal enterotoxin B gene (Seb). A total of 200 milk and cheese samples were screened. One hundred ten isolates of Staphylococcus aureus pre-confirmed using selective and differential media with biochemical tests. Genomic DNA was extracted from the isolates and the SEB gene detects using conventional PCR with specific primers. Three staphylococcus aureus isolates were found to be positive for Seb gene using PCR and confirmed by sequencing. Sequence homology showed variety range of identity starting from (100% to 38%). Phylogenetic tree analyses show that samples (6 and 5) are correlated with S. epidermidis. This study discovered that isolates (A6-RLQ and A5-RLQ) are significantly clustered in a group with non- human pathogen Staphylococcus agnetis.

The occurrence of pyridoxamine phosphate in milk

1961 ◽  
Vol 28 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Margaret E. Gregory ◽  
L. A. Mabbitt
Keyword(s):  
Acid Treatment ◽  
Vitamin B ◽  
Total Vitamin ◽  
Active Compounds ◽  
Milk Samples ◽  
Fresh Milk ◽  
Freeze Dried ◽  
Processing And Storage ◽  
And Storage ◽  
Mild Acid

SummaryThe presence of pyridoxamine phosphate in extracts of freeze-dried raw and evaporated milks has been demonstrated by separation and identification of the vitamin B6 active compounds by chromatography and electrophoresis on paper. Its presence in the milk extracts is the cause of the higher values for vitamin B6 activity measured with Streptococcus faecalis as compared with those obtained with Str. faecium or Saccharomyces carlsbergensis. This is because Str. faecalis can utilize the phosphate for growth as readily as free pyridoxamine, whereas Str. faecium and S. carlsbergensis cannot. The mild acid treatment used for extracting the vitamin B6 active compounds from the milk samples for microbiological assay was found to be insufficient to hydrolyse the pyridoxamine phosphate. Further treatment of the acid extracts with intestinal phosphatase released the pyridoxamine from its phosphate and increased the vitamin B6 activity measured with S. carlsbergensis and Str.faecium so that the total vitamin B6 activities of the freeze-dried raw and evaporated milks measured microbiologiclly, were then in agreement with the values found in previous tests with chicks and rats.Pyridoxamine phosphate could only be detected in small amounts in a sample of fresh milk. The possibility that more of it was formed during the processing and storage of the freeze-dried samples is discussed.

scholarly journals Prevalence and antibiotic susceptibility profile of Staphylococcus aureus from milk and milk products in Nasarawa State, Nigeria

2020 ◽  
Vol 18 (1) ◽  
pp. 1-12
Author(s):  
A. Yakubu ◽  
I.O Abdullahi ◽  
C.Z. Whong ◽  
B. Olayinka
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Susceptibility ◽  
Hazard Analysis ◽  
Raw Milk ◽  
Fermented Milk ◽  
Milk Products ◽  
Milk Samples ◽  
Critical Control Points ◽  
Agar Disc ◽  
Resistance Patterns

This study determined the prevalence and antibiotic susceptibility profile of Staphylococcus aureus isolated from milk and milk products in Nasarawa State, Nigeria. A total of 180 samples comprising of fresh raw milk, bulk milk, Nono, and Kindirmo were collected over a period of 6 months. Standard microbiological procedures were employed in the isolation, identification, characterization and determination of the antibiogram of S. aureus from the milk samples. Characterization was achieved by morphological, biochemical characteristics using conventional methods and Microgen® STAPH-ID kits. The isolates were tested for susceptibility or resistance to a panel of 11 commonly used antibiotics using the agar disc diffusion technique. Out of the 180 milk samples examined, nine (9) S. aureus were isolated giving a prevalence of 5.0%. The occurrence of S. aureus was higher in Nono (12.1%) and Kindirmo (10.6%) than in fresh raw milk (5.9%). The kind of water (well water) used for cleaning utensils at the Nono and Kindirmo selling points was found to be a risk factor associated with the occurrence of S. aureus in the products. All of the isolates were resistant to cefoxitin (100%), ampicillin (100%), and amoxicillin/clavulanic acid (100%). The isolates displayed various rates of resistance to erythromycin (22.2%), sulphamethoxazole/trimethoprim (22.2%), and tetracycline (44.4%). Five (5) antibiotic resistance patterns were recorded among the isolates an indication of different levels of use and misuse of antibiotics in the areas studied. The detection of Staphylococcus aureus in fresh and fermented milk in the areas studied suggests that consumption of dairy products especially those produced using traditional methods, constitute a hazard to consumers. It is recommended that since compliance with basic hygiene requirements is not guaranteed, hazard analysis and critical control points (HACCP) concepts should be seen as a part of an effective total hygiene concept at the selling points. Keywords: Antibiotic susceptibility profile, Milk, Nasarawa State, Nigeria, Prevalence, Staphylococcus aureus

scholarly journals Molecular Detection of Staphylococcal Enterotoxins and mecA Genes Products in Selected Food Samples Collected from Different Areas in Khartoum State

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mohammed Yahya Ahmed ◽  
Hashim Abdalbagi Ali ◽  
Babbiker Mohammed Taher Gorish ◽  
Sara Omer Ali ◽  
Eman Saif Aldein Abdalrhim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Meca Gene ◽  
Food Poisoning ◽  
Meat Products ◽  
Low Frequency ◽  
Raw Milk ◽  
Food Samples ◽  
Increased Risk ◽  
Enterotoxin B ◽  
Staphylococcus Aureus Enterotoxins

Staphylococcal food poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Nowadays, many researchers worldwide noted an emergence of resistant strains such as Staphylococci particularly for the antibiotic methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes, in selected food samples. A total of 400 selected food samples were collected from different areas in Khartoum State. The selected foods included cheese, meat products, fish, and raw milk. One hundred samples from each type of food were cultivated, and the resultant growth yielded 137 (34.25%) S. aureus, 126 (31.5%) bacteria other than S. aureus, and 137 (34.25%) yielded no growth. Eighty-four of the 137 S. aureus isolates were randomly selected and tested for the presence of mecA and enterotoxin genes. The oxacillin sensitivity test showed that 15 (11%) of 137 S. aureus isolates were oxacillin resistant. The PCR assay showed that the mecA gene was detected in 15 of 84 (17%) S. aureus isolates. Simultaneously, only 2 (2.385%) out of 84 S. aureus isolates showed an enterotoxin B gene product. There was a relatively moderate prevalence of methicillin-resistant Staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of selected food samples collected from Khartoum State. These findings elucidate the increased risk on public in Khartoum being affected by Staphylococcal food poisoning upon consumption of dairy or meat products prepared in unhygienic conditions that could lead to intoxication by Staphylococcus aureus enterotoxins.

Preservation and Storage Mechanisms for Raw Milk Samples for Use in Milk-Recording Schemes

1996 ◽  
Vol 59 (2) ◽  
pp. 151-154 ◽  
Author(s):  
HUMBERTO G. MONARDES ◽  
ROBERT K. MOORE ◽  
BRIAN CORRIGAN ◽  
YVON RIOUX
Keyword(s):  
Cell Count ◽  
Somatic Cell Count ◽  
Potassium Dichromate ◽  
Dairy Herd ◽  
Raw Milk ◽  
Storage Conditions ◽  
Sample Storage ◽  
Milk Samples ◽  
Whole Process ◽  
And Storage

This study, carried out by the Quebec Dairy Herd Analysis Service, compares (during summer conditions in Quebec) the performance of three types of preservatives for raw milk under four different systems of sample storage: no refrigeration, refrigeration at the laboratory only, refrigeration during transport and at the lab, and complete refrigeration from sampling at the farm to analysis. The objective was to determine the best preservative and storage conditions for protecting milk components during transportation and storage of raw milk samples collected at the farm and sent to a central testing lab for analysis. Milk samples were analyzed at day 3 and at day 7 after sampling to observe the effect of aging. A total of 12,480 samples were collected during the trial. The components studied were percentage of fat and protein and somatic cell count (SCC). In general, samples preserved with bronopol (2-bromo-2-nitropropane-1,3-diol and 2-bromo-2-nitropropanol) in liquid or in microtab tended to give higher readings for fat and protein contents than samples preserved with potassium dichromate. Significantly lower fat values were observed in 7-day-old samples compared to 3-day-old samples. Fat depression was more accentuated in nonrefrigerated samples. Under current methods of handling raw milk samples, refrigeration during the whole process of sampling, transportation, and until analysis, seems an ideal to attain to avoid significant reductions of fat values.

scholarly journals Influence of soft cheese technology on the growth and enterotoxin production of Staphylococcus aureus

2009 ◽  
Vol 27 (No. 2) ◽  
pp. 127-133 ◽  
Author(s):  
L. Necidová ◽  
Z. Šťástková ◽  
M. Pospíšilová ◽  
B. Janštová ◽  
J. Strejček ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Technological Process ◽  
Raw Milk ◽  
Toxin Production ◽  
Milk Products ◽  
Model Experiments ◽  
Soft Cheese ◽  
Strict Compliance ◽  
Technological Processing ◽  
And Storage

The aim of this study was to monitor <I>S. aureus</I> growth and toxin production in soft cheese during the technological processing. In model experiments, raw milk was inoculated separately with five <I>S. aureus</I> strains isolated from milk and milk products. All the strains were producers of staphylococcal enterotoxins (SEs) of types A, B, or C. SEs were detected by the enzyme-linked fluorescence assay (ELFA) performed in the MiniVIDAS device. This study has shown that the amount of SEs varied with the tested strains and stages of the technological process. SEs were detected in soft cheese made from pasteurised milk inoculated with 2.9 × 10<sup>5</sup> CFU/g of <I>S. aureus</I>. The prevention of <I>S. aureus</I> contamination and multiplication during the cheese making process is a prerequisite for the production of safe soft cheese. The most important enterotoxin dose build-up factor can be overcome by strict compliance with the cooling requirements during the manufacture, distribution and storage of the product.

BACTERIAL COUNTS OF RAW MILK AND FLAVOR OF THE MILK AFTER PASTEURIZATION AND STORAGE

1972 ◽  
Vol 35 (4) ◽  
pp. 203-206 ◽  
Author(s):  
G. B. Patel ◽  
G. Blankenagel
Keyword(s):  
Raw Milk ◽  
Bacterial Counts ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Standard Plate ◽  
Plate Counts ◽  
Subsequent Storage ◽  
And Storage ◽  
Common Defect

A total of 216 raw milk samples with a variety of Standard Plate Counts and psychrotrophic bacteria counts were laboratory-pasteurized, stored at 7 C, and then evaluated for flavor after 1 and 2 weeks. Results showed that milk with counts of &gt;1,000,000/ml before heating frequently developed objectionable flavors after pasteurization and subsequent storage. The most common defect was a bitter flavor which appeared within 2 weeks after pasteurization in nearly all samples which as raw milk had counts exceeding 10,000,000/ml. This off-flavor developed in spite of small numbers of organisms in the pasteurized product and in the absence of post-pasteurization contamination.

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