The keystone of all prerequisite programs (PRPs) in any food processing or service operation has to be “personnel personal hygiene.” If workers’ hygienic practices are improper or slipshod, then the sanitation standard operating procedures for environmental and food equipment can and do become critically compromised.
Explore this issueJune/July 2016
Ongoing Problems with Hygiene
Despite common sense and extensive training tools that the food industry utilizes from farm to fork, there are still major issues with personal hygiene, resulting in serious foodborne disease outbreaks. In an extensive review series on the examination of food workers’ roles and contributions to foodborne disease outbreaks, Todd et al researched food worker hygiene issues from every angle. In Part 3 of the review series that appeared in the Journal of Food Protection, a total of 816 outbreaks were analyzed. In many instances, infected food workers were handling food with bare hands and had poor handwashing practices. A majority of the infected implicated workers were either shedders or had poor personal hygiene behaviors. The microbial pathogens had norovirus as the largest culprit followed by Salmonella spp. then S. aureus. A total of eight categories of outbreak types were analyzed. The most problematic category involved infected workers who deny their illness and remain unreported in the outbreak data. In all scenarios, the lack or disregard of basic hygiene practices when a food worker or family member has a microbial-borne illness is still profoundly common.
Further complicating the category factors, as seen in Part 5 of this series, even when workers understand they are ill, and workers and their managers try to prevent the microbial spread of the shedded pathogens, it’s difficult to screen and segregate all infected carriers with no symptoms. Also, even after ill infected workers leave the premises, they might already have contaminated food contact and environmental surfaces with residue of sputum, vomitus, or fecal matter that is almost impossible to track to properly disinfect contaminated surfaces. Many of these viral or bacterial pathogens can and do survive for long durations on inanimate surfaces, cross-contaminating ready-to-eat (RTE) food products.
Hand and Basic Surface Hygiene
While norovirus foodborne illness outbreaks are not fatal in most instances, they are the source of the majority of known outbreaks. Hepatitis A outbreaks in food handling are less common than norovirus, but Hep A has shown a propensity to be transferred from hands to equipment to products. If you can control norovirus contamination in your facility, the same practices and measures will work well for controlling Hepatitis A.
In one study published in Applied and Environmental Microbiology, finger pads—used to mimic gloves—were utilized as a model to assess Hepatitis A viral particle transfer from hands or gloves to RTE produce (i.e. lettuce). The greater the water volume used, and especially if soap and glove sanitizer (alcohol-based products) were applied, the higher the viral particle removal. Overall, Hep A adhered far better to skin than to disposable gloves.
Norovirus and some surrogate viral strains also displayed a lengthy survival on typical non-porous food contact surfaces. As the cruise ship industry has discovered, studies in food facilities demonstrate that norovirus can survive on food contact surfaces—staying infective for weeks. Unclean employee hands and contaminated equipment/cleaning utensils can transfer the Norwalk virus. A study in Journal of Food Protection discussed the need to utilize norovirus surrogates to truly assess survival rates on Zones 1 thru 3 to create realistic risk assessments on norovirus transfer from infected workers.
There seems to be a high risk of contamination of food ingredients and products from Norwalk virus and Hep A infected workers via the direct/indirect food contact surfaces serving as the intermediate. So once gloves are contaminated from an infected food handler, the virus easily adheres to and survives on Zone 1 and Zone 2 surfaces, creating a major cross-contamination concern. This viral transfer is enhanced if the food product has a high water activity and a porous surface.