Microbial Risk Assessment: Salmonella in Chicken

This is a reconstruction of paper from Oscar 2004. He used @Risk software to carry out the risk assessment. I am reconstructing his paper using R- software taking the same model input values. So for details, please refer to the paper of Oscar 2004. The following are the important model parameters described in that paper.

Model design

The following 5 nodes were considered during model development.

Node 1- Retail

"The incidence of Salmonella contamination of whole chickens ranged from 0% to 100% with a median value of 30%. The MPN of Salmonella on contaminated whole chickens is low, often below 10 MPN, whereas the maximum MPN per chicken ranges from >300 to >1100. A minimum value of 1 MPN (by definition, the minimum level of contamination that is possible), a median value of 10 MPN, and a maximum value of 450 MPN per chicken were used to define the input settings for the PERT distribution for the extent of Salmonella contamination of ready-to-cook whole chickens at retail."

Microbial Risk Assessment: Salmonella in Peanut butter: graphs

Have you already read the first part titled:

Microbial Risk Assessment: A case study of salmonella in peanut butter

If you have not read that part, first you should read that part before looking at these graphs. This is graphical output of that microbial risk assessment using Monte Carlo simulation.

Microbial Risk Assessment: Salmonella in Peanut butter

Do you know the case of salmonella outbreak from peanut butter in America?

Background:

In 2008/2009, 9 people died and at least 714 people (half of them children) fell ill, all from food poisoning after eating products containing salmonella contaminated peanuts. It triggered the most extensive food recall in US involving 46 states, more than 360 companies, and more than 3,900 different products manufactured using Peanut Corporation of America (PCA) ingredients. In September 2015, Stewart Parnell was sentenced to 28 years in prison for his role in the nationwide outbreak.( for details check Wikipedia)

Microbial Risk Assessment

Let’s carry out microbial risk assessment of salmonella from peanut butter. The assumption of this case study is taken from the paper of Chen 2013.

The salmonella is not very common in peanut. Based on the historical data, the initial prevalence of salmonella in peanut during manufacturing is estimated to be 5.5 x 10^-6 (i.e. 55 units out of 10⁷ units could be contaminated with salmonella).