Best practices to keep Salmonella at bay

If you’ve been keeping your eyes on the food safety news of the last few months, you’ll have noticed that an outbreak of Salmonella is ongoing in the United States. As of Oct. 28, 2021, 37 states have been affected and more than 650 people have been reported sick, with 129 hospitalizations. No deaths have been recorded as of that date. Although the number of illnesses attributed to this outbreak is high, it is possible the actual number is much higher in that some people did not report their symptoms.

The outbreak is being traced back to whole, raw, red, white and yellow onions from ProSource Produce LLC and Keeler Family Farms. These onions were imported to the United States from Chihuahua, Mexico. Since onions typically feature a shelf life of up to three months, there is a possibility of product still being in commerce. The contaminated product is being sold in mesh sacks ranging from 50 to 2 lbs.; and cartons ranging from 50 to 5 lbs.

Salmonella infection causes an illness called salmonellosis. The symptoms can show up anywhere between six hours and six days after infection. Symptoms typically last between 4-7 days and usually can be resolved without medical treatment. Thus, it’s particularly difficult to track and accurately count the number of people affected. Salmonella lives in the intestines of humans and animals. People can become infected by eating contaminated food or drinking contaminated water, or via direct contact with infected animals.

How do processors help consumers from becoming infected? First, it is important for both processors and consumers to be aware of pathogen growth and have controls in place to prevent growth from occurring.

Things processors can do include: meeting lethality requirements, receiving COAs, maintaining storage conditions, have pest control plans in place, monitor air quality, have an employee health policy, and ensure proper water drainage.

We all know raw poultry and eggs are known sources of Salmonella, and that reaching lethality during processing will destroy it. However, Salmonella is also common in dry conditions. and difficult to detect there. It can be killed by heat, but that won’t help prevent contamination if it is present in ingredients applied to already cooked product. Therefore, it’s crucial that processors know their dry-goods suppliers and receive COAs, to prevent contamination of already cooked product.

Another thing to be aware of is pest control. Pigeons, rats and mice are known carriers of Salmonella in the food industry. Even if you don’t have these pests in your facility, be aware that Salmonella can still enter the plant via employees’ boots or forklifts that drive outside and back inside. Use of boot wash stations and cleaning of forklift tires can help maintain sanitary conditions and keep pathogens like Salmonella from infiltrating the facility.

The environment of the facility is also a big factory. Plants located in rural areas may need to monitor air quality at a higher level and change filters more often. This is particularly important if the plant is near a farm, as contaminants could enter the plant via the ventilation system.

Humans can also be a source of Salmonella entering the plant if they are infected and continue to work. All employees should be washing their hands properly and staying home if they are sick. Facilities should log employee health, and if an employee went home sick, the reason they went home should be recorded. This is confidential information that should not be shared, but it may turn out to be helpful should a recall happen.

Water is not a source of Salmonella, but it can aid in the survival of the pathogen in the plant environment. Proper drainage that prevents water from pooling decreases the chances that Salmonella will survive and grow.

For consumers there are a few key things to do to help prevent getting sick. Processors should always remind their consumers to follow these guidelines. Consumers should clean, separate, cook and chill.

Washing hands, utensils, and any produce reduces the risk of cross-contamination. All produce should be washed prior to cutting or peeling to reduce pathogens. Hands and utensils should be washed in between contact with raw and cooked foods.

Separating food that won’t be cooked from raw meat, poultry and seafood limits chances of cross-contamination. Not only is this important during meal preparation, but it should be considered when putting groceries away. Raw products should be kept on the bottom shelf of the refrigerator to prevent any leakage from dripping on to ready-to-eat foods.

Cooking food thoroughly eliminates the chances of obtaining Salmonella from raw product.

Chilling perishable foods within two hours of being out, and thawing food in the fridge instead of at room temperature, both limit the possibility of pathogen growth.

Salmonella is a common, pesky pathogen that is difficult to eliminate should it enter your plant. It is easier to be aware of how Salmonella can enter your facility and have controls in place to limit the ability for it to grow. By instituting and installing as many of the preventative measures mentioned above, processors and consumers can safely enjoy foods without as much concern for getting sick from Salmonella.

— Sam Bibbs, food safety consultant, sam@werfoodsafety.com

Salmonellosis outbreak from ’95 does NOT support humidity as a critical parameter in jerky processing

I just had a rather enlightening conversation with a senior USDA-FSIS official about the need for humidity during jerky manufacturing.

I asked, “How does humidity destroy pathogens?”

The official really didn’t know the answer, but he did state that, without humidity, pathogens can become heat-resistant, and Salmonella can grow and survive normal lethality.

When I asked for the studies that backed up these statements, the official pointed to the same studies they always do. I then explained how those studies didn’t actually take product to lethality (i.e., what was surviving was only surviving longer than the non-treated Salmonella). The official countered by citing the salmonellosis outbreak from 1995 in New Mexico — as is typical of this conversation.

Here, too, the problem with citing that case is lethality, as the product implicated in that outbreak should be considered a raw beef jerky, not fully cooked.

Per the published outbreak report by the CDC (https://www.cdc.gov/mmwr/preview/mmwrhtml/00039423.htm), partially frozen product was placed on racks and was pushed into a drying room. The chamber temperature (not the product’s internal temperature) was set at 140 F for three hours, then reduced to 115 F for approximately 19 hours. Therefore, the product was never exposed to a lethality treatment, and hence, by definition, it was a raw product. The report also states that no product temperatures were ever recorded.  

I promised to send the official the CDC report to remind them (or make them aware) that the production technique that was used resulted in a raw product that clearly wasn’t ready to eat (and that doesn’t even factor in other inputs or lack of them, such as sanitation, equipment, plant elevation, etc.).

It’s a shame this conversation even needed to happen, and that we have to point this out about a case more than 25 years in the past. However, it’s not the only time we’ve had these conversations lately — we have been seeing more and more actions by USDA-FSIS around humidity requirements based on these incorrect assumptions and faulty arguments. When we bring up actual science around heat resistance and pathogen growth, little discussion occurs, and FSIS inevitably falls back on the New Mexico outbreak as their “final answer” for why humidity is needed in jerky processing.

Is humidity during processing a control factor? Yes, as it assists in heat transfer. When you are measuring the internal temperature of a product, you are, in fact, measuring the transfer of energy into the product. One way to increase the rate of transfer is to increase the humidity in your cooking vessel.  At home, when you boil something, it cooks faster than it would if you cooked it in a pan, given the same energy input. But that doesn’t make humidity a critical parameter, it makes it a supporting parameter. The critical parameter is the rapid transfer of energy into the product to denature the proteins of the pathogens, rendering them non-viable (killing them). You measure this energy transfer by using internal product temperature monitoring devices.  

The entire paradigm of “chamber” temperature and “chamber” humidity now falls on a very niche part of the industry (who implement and know their process — and make some great products!). It doesn’t apply to the vast majority of the industry making jerky or other shelf-stable products.

HACCP is about analyzing for hazards, not creating a plan and then making products. Know your process and apply your controls, and you’ll be in great shape.

However, unless you want to spend a lot of time arguing with regulators, point to the sentence in the 1999 version of Appendix A, which allows you to rely on a sealed oven during cooking as the evidence of how you deal with heat transfer. I promise you that it will be a lot less frustrating!

— Andrew Lorenz, president, We R Food Safety!, andrew@werfoodsafety.com