Antibiotic Susceptibility, Biofilm-Forming Ability, and Incidence of Class 1 Integron of Salmonella spp., Escherichia coli, and Staphylococcus aureus Isolated from Various Foods in a School Canteen in China

2020 ◽  
Vol 17 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Wen Wang ◽  
Li Wang ◽  
Jianyu Su ◽  
Zhenbo Xu
2014 ◽  
Vol 77 (8) ◽  
pp. 1275-1288 ◽  
Author(s):  
WAN MEI LEONG ◽  
RENAE GEIER ◽  
SARAH ENGSTROM ◽  
STEVE INGHAM ◽  
BARBARA INGHAM ◽  
...  

Potentially hazardous foods require time/temperature control for safety. According to the U.S. Food and Drug Administration Food Code, most cheeses are potentially hazardous foods based on pH and water activity, and a product assessment is required to evaluate safety of storage >6 h at 21°C. We tested the ability of 67 market cheeses to support growth of Listeria monocytogenes (LM), Salmonella spp. (SALM), Escherichia coli O157:H7 (EC), and Staphylococcus aureus (SA) over 15 days at 25°C. Hard (Asiago and Cheddar), semi-hard (Colby and Havarti), and soft cheeses (mozzarella and Mexican-style), and reduced-sodium or reduced-fat types were tested. Single-pathogen cocktails were prepared and individually inoculated onto cheese slices (~105 CFU/g). Cocktails were 10 strains of L. monocytogenes, 6 of Salmonella spp., or 5 of E. coli O157:H7 or S. aureus. Inoculated slices were vacuum packaged and stored at 25°C for ≤15 days, with surviving inocula enumerated every 3 days. Percent salt-in-the-moisture phase, percent titratable acidity, pH, water activity, and levels of indigenous/starter bacteria were measured. Pathogens did not grow on 53 cheeses, while 14 cheeses supported growth of SA, 6 of SALM, 4 of LM, and 3 of EC. Of the cheeses supporting pathogen growth, all supported growth of SA, ranging from 0.57 to 3.08 log CFU/g (average 1.70 log CFU/g). Growth of SALM, LM, and EC ranged from 1.01 to 3.02 log CFU/g (average 2.05 log CFU/g), 0.60 to 2.68 log CFU/g (average 1.60 log CFU/g), and 0.41 to 2.90 log CFU/g (average 1.69 log CFU/g), respectively. Pathogen growth varied within cheese types or lots. Pathogen growth was influenced by pH and percent salt-in-the-moisture phase, and these two factors were used to establish growth/no-growth boundary conditions for safe, extended storage (≤25°C) of pasteurized milk cheeses. Pathogen growth/no-growth could not be predicted for Swiss-style cheeses, mold-ripened or bacterial surface–ripened cheeses, and cheeses made with nonbovine milk, as insufficient data were gathered. This challenge study data can support science-based decision making in a regulatory framework.


2020 ◽  
Vol 8 (3) ◽  
pp. 82-86
Author(s):  
Shyamala Rai ◽  
Barsha Karki ◽  
Sujita Humagain ◽  
Sandesh Rimal ◽  
Sandhya Adhikari ◽  
...  

The emergence of antibiotic resistance in microorganisms and the presence of such isolates in milk pose a great risk to public health. Therefore, this study aims to determine the antibiotic susceptibility pattern of Escherichia coli and Staphylococcus aureus isolated from milk and assess the microbial quality of milk. For this, a total of 70 milk samples were collected and the total bacterial count (TBC) was determined. E. coli and S. aureus were isolated using their respective selective media while antibiotic susceptibility testing was carried out by Kirby Bauer Disc Diffusion method. The TBC showed that the raw milk samples contained two-fold higher microbial load while the pasteurized milk samples contained four-fold higher microbial loads than the standard guidelines. A total of 62 isolates were identified from culture-positive milk samples of which 32 were E. coli and 30 were S. aureus. A significant correlation was observed between microbial load and the organism isolated (r = 0.339, p<0.01). All S. aureus isolates were susceptible to Chloramphenicol while 40% were resistant to Cefoxitin, indicating the presence of Methicillin resistant S. aureus (MRSA). Also, 12 multidrug resistant (MDR) S. aureus were identified. While for E. coli, all were susceptible to Chloramphenicol but resistant to Ampicillin. Also, 9 MDR E. coli were detected. Higher resistance was observed among isolates from the raw milk samples than the pasteurized milk. It can be concluded that the milk produced by small-scale farms and dairy industries of Kathmandu district are of poor quality. Hence, routine microbial quality assessment and antimicrobial resistance monitoring should be followed to safeguard public health.


Author(s):  
Samuel Ekene Odo ◽  
Chidiebere Francis Uchechukwu ◽  
Ugochi Rita Ezemadu

The prevalence of foodborne diseases in Nigeria is alarming despite efforts by Government and Non-governmental Organizations to prevent the spread of foodborne pathogens. Health and socio-economic implications of foodborne diseases are enormous, including loss of productivity and low quality of life. In Nigeria, most people eat food at least once outside their homes every day. Food is an indispensable basic need of all humans and animals to sustain a healthy, reproductive and productive life. Humans are very active and highly productive when they consume safe food and are in a state of good health; however, consuming food already contaminated with microbial pathogens or its products such as Escherichia coli  0157:H7, Salmonella spp., Shigella spp., Clostridium spp., Campylobacter spp., and Staphylococcus aureus-toxin to a harmful level can cause severe illnesses and even progress to death. Therefore, it is essential for food handlers and vendors to maintain proper personal hygiene, undergo regular health checks, constantly improve environmental sanitation and adequately prepare food to prevent the spread of foodborne diseases. Consumers of ready-to-eat foods and food products should consider the overall safety of the food; environment where the food was prepared, where and how the food is distributed in order to mitigate likely foodborne infections and diseases. Water used in preparing food and watering animals should be clean and safe.


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