Food Safety Risk Factors and Their Importance
This blog frequently discusses food safety risk factors, including time and temperature abuse, employee personal hygiene, cross-contamination, and inadequate cleaning/sanitizing. Readers might wonder how these risk factors contribute to foodborne illness.
One responsibility of the Centers for Disease Control (CDC) is to compile statistics on the causes of foodborne illness outbreaks, as they are reported by local or state health departments. Food safety risk factors are included in these reports.
First, a qualifier on these results. The results often rely on the establishment personnel’s self-reporting and might be biased, less than the true numbers. In addition, foodborne illnesses and their contributing risk factors often go unreported, for any number of reasons. Symptoms might be confused with other illnesses or be so mild as to go unnoticed. The onset times for illnesses vary depending on the dose of food consumed and the health of the ill person. The suspect food might not be available for analysis. Often, an investigation begins sometime after the actual illness event, so information is difficult to recall accurately.
More than one risk factor is often included in these reports. For example, cross-contamination may occur along with poor personal hygiene, improper cleaning and sanitizing, contaminated food supplies, and food preparation practices. In other cases, the report is incomplete, and no causes are identified.
During 2017–2019, a total of 800 foodborne illness outbreaks associated with 875 retail food establishments were reported by state and local health departments. The report is lengthy and complicated, but the reader is encouraged to review it: the citation is at the end of this article. Here are the important points from this report:
• 69.4% had a confirmed or suspected agent. Viruses (norovirus), bacteria (salmonella), parasites (cyclospora), and chemicals (scombroid or histamine) accounted for 48.1%, 46.8%, 13% and 14% respectively.
Of the 800 outbreaks investigated, a large percentage was caused either by a bacterium (Salmonella) or a virus (Norovirus). These two causes account for 55.6% of all cases.
Within the group of viruses, Norovirus continues to be a prominent cause, as it has for quite a few years. The public demands ready-to-eat foods such as salads and sandwiches, foods with no further cooking step, and these foods are vulnerable to hand contamination. In this report, the most common contributing factor was contamination by a food worker suspected of having an infectious illness. Contamination was spread either through the air (aerosols from vomit) or bare-hand contact.
While the food law requires a written policy and employee training regarding restrictions and exclusions of ill employees, only 62.4% of the managers interviewed said there was a written policy to that effect. However, only 17% of these policies included all information required by law. This indicates that any employee training or standard operating procedures might not be complete, either.
The second major group, bacterial causes, 46.8% of the cases, were from Salmonella, Escherichia coli O157:H7, or Clostridium perfringens, that either exist at unsafe levels in foods (e.g., in ground beef) or have contaminated food at a certain point in the food chain. In these cases, the contaminated food did not go through a kill step or the step was inadequate (undercooking, improper cooling, or inadequate reheating). Time-temperature abuse is a prominent cause of illness, as it has been for many years. Of particular note, improper or slow cooling accounts for 10.6% of all outbreaks, at least 80 of the 800 cases.
Taken together, these findings are a reminder that following the Food Code guidance on cross-contamination prevention and proper cooking, reheating, holding, and cooling of food is important to prevent bacterial illness.
Appendices copied from the article:
(1) Top five contributing factors to foodborne illness outbreaks
(A) Other mode of contamination by a food handler, worker, or preparer who was suspected of having an infectious illness;
(B) Contaminated raw product (the suspect food was intended to be consumed raw, undercooked, or under processed)
(C) Bare hand contact with ready-to-eat food by a food worker who was suspected of having an infectious illness
(D) Cross-contamination of ingredients
(E) Unspecified source of contamination
Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report Surveillance Summaries V. 72 (6) 6/2/23 ‘Foodborne Illness Outbreaks at Retail Food Establishments — National Environmental Assessment Reporting System, 25 State and Local Health Departments, 2017–2019’