Wiley Online
According to Codex Alimentarius Commission recommendations, management options applied at the process production level should be based on good hygiene practices, HACCP system, and new risk management metrics such as the food safety objective. To follow this last recommendation, the use of quantitative microbiological risk assessment is an appealing approach to link new risk-based metrics to management options that may be applied by food operators.
Through a specific case study, Listeria monocytogenes in soft cheese made from pasteurized milk, the objective of the present article is to practically show how quantitative risk assessment could be used to direct potential intervention strategies at different food processing steps.
Based on many assumptions, the model developed estimates the risk of listeriosis at the moment of consumption taking into account the entire manufacturing process and potential sources of contamination. From pasteurization to consumption, the amplification of a primo-contamination event of the milk, the fresh cheese or the process environment is simulated, over time, space, and between products, accounting for the impact of management options, such as hygienic operations and sampling plans. A sensitivity analysis of the model will help orientating data to be collected prioritarily for the improvement and the validation of the model.
What-if scenarios were simulated and allowed for the identification of major parameters contributing to the risk of listeriosis and the optimization of preventive and corrective measures.
Dairy Foods
In 1985, the world changed for the dairy industry. The New England Journal of Medicine reported that from Jan. 1 to Aug. 15, there were 142 confirmed cases and 48 deaths associated with listeriosis, a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes.
The cases were centered in the local Hispanic population of Los Angeles. These were “confirmed” cases; however, the actual number is estimated to be significantly higher. The outbreak was eventually linked to Jalisco Mexican Products Inc., commonly known as “Jalisco Cheese.” Investigators determined that an unknown portion of the milk used to make the company’s fresh Mexican-style cheeses was not pasteurized. This was not by mistake. Raw milk added to pasteurized milk enhanced the flavor of the cheese, giving it a slight rancid flavor.
At the time, we knew virtually nothing about Listeria. We were asking:
- What is it and how pathogenic is it?
- Where did it come from?
- How does it grow?
- Can we control it?
But the most important questions in 1985 were: Will sanitizers destroy it and does it survive pasteurization?
