Validation of growth models for Listeria monocytogenes and Yersinia enterocolitica in cooked chicken meat

ABSTRACT In this study, we investigated the fate of Listeria monocytogenes, pathogenic Yersinia enterocolitica, and Escherichia coli O157:H7 gfp+ inoculated in low numbers into ready-to-eat baby spinach and mixed-ingredient salad (baby spinach with chicken meat). Samples were stored at recommended maximum refrigerator temperature (8°C in Sweden) or at an abuse temperature (15°C) for up to 7 days. Mixed-ingredient salad supported considerable growth when stored at 15°C during shelf life (3 days), with populations of L. monocytogenes, pathogenic Y. enterocolitica, and E. coli O157:H7 gfp+ increasing from less than 2.0 log CFU/g on day 0 to 7.0, 4.0, and 5.6 log CFU/g, respectively. However, when mixed-ingredient salad was stored at 8°C during shelf life, only L. monocytogenes increased significantly, reaching 3.0 log CFU/g within 3 days. In plain baby spinach, only pathogenic Y. enterocolitica populations increased significantly during storage for 7 days, and this was exclusively at an abuse temperature (15°C). Thus, mixing ready-to-eat leafy vegetables with chicken meat strongly influenced levels of inoculated strains during storage. To explore the food safety implications of these findings, bacterial numbers were translated into risks of infection by modeling. The risk of listeriosis (measured as probability of infection) was 16 times higher when consuming a mixed-ingredient salad stored at 8°C at the end of shelf life, or 200,000 times higher when stored at 15°C, compared with when consuming it on the day of inoculation. This indicates that efforts should focus on preventing temperature abuse during storage to mitigate the risk of listeriosis. The storage conditions recommended for mixed-ingredient salads in Sweden (maximum 8°C for 3 days) did not prevent growth of L. monocytogenes in baby spinach mixed with chicken meat. Manufacturers preparing these salads should be aware of this, and recommended storage temperature should be revised downwards to reduce the risk of foodborne disease.

Download Full-text

Effect of Ozone on the Inactivation of Yersinia enterocolitica and the Reduction of Natural Flora on Potatoes

Journal of Food Protection ◽

10.4315/0362-028x-69.10.2357 ◽

2006 ◽

Vol 69 (10) ◽

pp. 2357-2363 ◽

Cited By ~ 32

Author(s):

MARÍA VICTORIA SELMA ◽

DAVID BELTRÁN ◽

ELISEO CHACÓN-VERA ◽

MARÍA ISABEL GIL

Keyword(s):

Listeria Monocytogenes ◽

Yersinia Enterocolitica ◽

Disease Outbreaks ◽

Wash Water ◽

Foodborne Disease ◽

Pathogenic Microorganisms ◽

Psychrotrophic Bacteria ◽

Fresh Vegetables ◽

Natural Flora ◽

Soil Irrigation

Fresh vegetables contaminated with Yersinia enterocolitica have been implicated in foodborne disease outbreaks. Surfaces of vegetables can become contaminated with pathogenic microorganisms through contact with soil, irrigation water, fertilizers, equipment, humans, and animals. One approach to reduce this contamination is to treat fresh produce with sanitizers. In this study, the ability of ozone to inactivate Y. enterocolitica inoculated in water and on potato surfaces was evaluated. Furthermore, the efficacy of ozone in reducing natural flora on whole potato was determined. Total aerobic mesophilic and psychrotrophic bacteria, total coliforms, and Listeria monocytogenes were enumerated. Finally, several disinfection kinetic models were considered to predict Y. enterocolitica inactivation with ozone. Treatments with ozone (1.4 and 1.9 ppm) for 1 min decreased the Y. enterocolitica population in water by 4.6 and 6.2 log CFU ml−1, respectively. Furthermore, ozonated water (5 ppm) for 1 min decreased Y. enterocolitica and L. monocytogenes from potato surfaces by 1.6 and 0.8 log CFU g−1, respectively. Therefore, ozone can be an effective treatment for disinfection of wash water and for reduction of potato surface contamination.

Download Full-text

Anti-bacterial effect of Rosmarinus officinalis Linn. extract and Origanum syriacum L. essential oil on survival and growth of total aerobic bacteria and Staphylococcus aureus using cooked chicken meat

Food Science and Technology ◽

10.1590/fst.60720 ◽

2021 ◽

Author(s):

Marwan AL-HIJAZEEN

Keyword(s):

Staphylococcus Aureus ◽

Essential Oil ◽

Chicken Meat ◽

Rosmarinus Officinalis ◽

Aerobic Bacteria ◽

Survival And Growth ◽

And Staphylococcus Aureus ◽

Cooked Chicken Meat ◽

Bacterial Effect

Download Full-text

Yersinia enterocolitica: Prevalence, virulence, and antimicrobial resistance from retail and processed meat in Egypt

Veterinary World ◽

10.14202/vetworld.2019.1078-1084 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1078-1084 ◽

Cited By ~ 1

Author(s):

Gamal Younis ◽

Mona Mady ◽

Amal Awad

Keyword(s):

Yersinia Enterocolitica ◽

Biofilm Formation ◽

Ground Beef ◽

Chicken Meat ◽

Diffusion Method ◽

Processed Meat ◽

Beef Meat ◽

Beef Burger ◽

Retail Chicken Meat

Aim: The objectives of this study were to investigate the prevalence of Yersinia enterocolitica in retail chicken meat, ground and processed beef meat, determine their virulence-associated genes, antimicrobial susceptibility pattern, molecular detection of extended-spectrum β-lactamases, and their capability of biofilm formation in vitro. Materials and Methods: A total of 210 samples (120 retail chicken meat, 30 ground beef, 30 beef burger, and 30 sausage samples) were collected from different retail chicken outlets and markets located at Mansoura city between December 2016 and April 2017. Meat samples were examined bacteriologically for the existence of Y. enterocolitica; bacterial colonies that displayed positive biochemical properties were subjected to polymerase chain reaction targeting 16 rRNA gene. Y. enterocolitica isolates were tested for their susceptibility to six antimicrobial agents using disk diffusion method. Uniplex PCR was used for screening Y. enterocolitica isolates for the presence of two virulence chromosome-associated genes (ail and yst), and β-lactamases (blaTEM and blaSHV). The capability of Y. enterocolitica to form biofilms was detected by tube method. Results: Thirty Y. enterocolitica isolates (14.29%) were recovered including 19 (15.83%) isolates from chicken meat, 3 (10%) from ground beef, 5 (16.67%) from beef burger, and 3 (10%) from sausage samples. Regarding ail gene, it was detected in 6.67% (2/30), while yst gene detected in 20% (6/30) Y. enterocolitica isolates. About 80%, 70%, 63.33%, and 50% of Y. enterocolitica isolates were sensitive to ciprofloxacin, gentamicin, cefotaxime, and streptomycin, respectively, while 83.33% of Y. enterocolitica isolates were resistant to both ampicillin and cephalothin. Interestingly, 21 (70%) isolates had the capability of biofilms formation in vitro. Among the multidrug-resistant (MDR) strains, a significant difference (p<0.05) was found between MDR and biofilm formation. However, biofilm formation was correlated with the resistance of the isolates to β-lactam antimicrobials and the presence of β-lactam-resistant genes. Conclusion: The presence of Y. enterocolitica in chicken meat, ground and processed beef meat represents a significant health risk for meat consumers, which reflects the contamination of slaughterhouses and processing operations, therefore, strict hygienic measures should be applied to minimize carcasses contamination.

Download Full-text

Verification of prediction of growth of Listeria monocytogenes micro-organism in chicken meat

Czech Journal of Food Sciences ◽

10.17221/8340-cjfs ◽

2000 ◽

Vol 18 (No. 5) ◽

pp. 183-186

Author(s):

A. Landfeld ◽

M. Karpíšková R Houška ◽

K. Kýhos ◽

P. Novotná

Keyword(s):

Listeria Monocytogenes ◽

Incubation Temperature ◽

Chicken Meat ◽

Raw Material ◽

Plate Count ◽

Raw Meat ◽

Total Plate Count ◽

Measured Water ◽

Number Of Bacteria ◽

Storage Temperatures

Raw chicken meat was comminuted and homogenised. There were measured water activity and pH (aw = 1 for temperature 25°C, pH = 5.8 for temperature 8°C). Input raw material was investigated for the presence of Listeria monocytogenes (negative) and the raw meat was inoculated by Listeria monocytogenes CCM 4699. Number of Listeria monocytogenes, total plate count and number of coliforms were determined in the range 0–7 days by bacteriological survey for the storage temperatures 4.9, 7 and 8.3°C. The increase of Listeria monocytogenes counts has been registered for temperature 4.9°C about log 1.5 CFU/g after 6 days, for temperatures 7 and 8.3°C about 2 log CFU/g (regarding to the starting counts). The prediction for listeria growth with the aid of Food MicroModel was also made. The best agreement between the experimentally analysed number of bacteria and prediction was received for the lowest incubation temperature 4.9°C.

Download Full-text