Tag Archives: foodborne illness

Foodborne Bacteria: Do You Know How They Grow?

Food safety concerns are on all food manufacturers’ minds (and, honestly, probably in their dreams too), so it is critical to know how bacteria grow.  Armed with that knowledge, we are better able to stay ahead of bacterial contamination in the food manufacturing facilities.

Petri dish with bacteria.

Petri dish with bacteria. Source: processingmagazine.com

Often, when I was in the plant environment, I would refer back to a case study put together by the Royal Society for Public Health in 2010. It laid out some excellent basics on growth factors for bacteria in a concise manner that readers of The Wide Line may appreciate.

The RSPH states, “In order to grow, bacteria require a source of nutrients, an appropriate atmosphere, neutral or alkaline conditions, available moisture and an appropriate temperature. (In turn), the nutrient source needs to have available moisture, a source of energy, nitrogen, vitamins, and minerals.” A large number of bacteria are able to grow with or without oxygen. Some bacteria (obligate aerobes), will only grow if oxygen is present. Other bacteria (obligate anaerobes) will only grow in the absence of oxygen.

The RSPH’s “Growth Requirements of Bacteria” section continues: “Most bacteria grow best in a neutral or alkaline environment. Bacteria do not grow well in foods which are too acidic (with a pH of less than 4.5).”  So, the more acidic the food, the less likely it is to support the growth of bacteria.  In addition, foods that are dried or high in salt or sugar have a reduction in available moisture content, and bacteria will grow poorly on these foods.

Finally, “Most bacteria will not grow in cold conditions, or will only grow and divide slowly. High temperatures will also inhibit the growth of bacteria.”  For example, most food poisoning bacteria die when exposed to a temperature of 70°C for two minutes or more. The optimum temperature range for the growth of most bacteria is 5°C to 63°C, which is known as the ‘temperature danger zone’.

The RSPH concisely acknowledges that there are multiple areas in all food production facilities that need to be assessed for risk regularly, as well as monitored daily in order to prevent microbiological product contamination. All processing steps have the potential to increase the chance of microbial corruption.  Nelson-Jameson carries food safety products that assist with control and surveillance in every step of the production process—from ingredient receiving through manufacturing, storage, and shipping of finished products.  Contact a sales representative today to find out how Nelson-Jameson can help strengthen your food safety prevention and protocol.

Tags: , , , , ,

Testing the Water

j0444789What is the difference between water activity and water “moisture” content? Well, it all depends on what you want to achieve. Do you want to monitor the amount of water and dry matter present in a product? Or do you want to increase and monitor the shelf stability of a product?

“Water ‘moisture’ content is the amount of water contained in a product”. Measuring water “moisture” content is better used to determine quality of the process. For example, if the product is a cheese powder that is spray dried, it is common practice to measure the water “moisture” content to determine yield and to ascertain if your drying process is running according to the diagnosed plan.

Water activity is defined as the measurement of the availability of free water for biological reactions—especially the biological reactions that can make humans and animals very sick.  Water activity is more critical in the food industry. Bacteria love water; gram-negative bacteria like E.coli need a minimum of .97 moisture content for growth, and the Staphylococcal toxin produced by Staphylococcus aureus only needs a minimum of .93 for growth. To put this into perspective, know that pure water’s moisture content is 1.00. Thus, it is critical for food manufacturers to know and monitor the water activity before, during, and after manufacturing for safety. See the table below for the water activity and content levels of common foods:

Water Activity of Common Foods (aw)

fresh meats and fish:                     0.99

moist cakes:                                       0.90-0.95

soy sauce:                                           0.80

jams, marmalades, jellies:            0.75-0.80

dried spices, milk powder:           0.20-0.60

Water Content of Common Foods (%)

apples:                 84

peppers:              92

salami, beef       60

dried fruit            31

wheat flour        11

Water activity is crucial to food safety. Microbes are everywhere, and will find any way possible to a food source, ultimately causing spoilage. Moisture analysis monitoring processes are set up to eliminate as many microbes as possible, with the key to moisture control and water activity being to find ways to bind the water so that it doesn’t allow microbes to find a food source—thus extending a product’s shelf life. Contact one of Nelson Jameson’s product specialists today to discuss your moisture analysis and water activity needs.

Tags: , , , , ,

Summer Food Safety for Moms-To-Be

Source: Downthemeadow.com

Source: Downthemeadow.com

Summer is here, and if you’re like us in the lab, you have sunshine, beaches, backyard cookouts, picnics, and Listeria monocytogenes on your mind. Warm weather and good food are two things we can all appreciate; however, unfortunately these conditions are also ideal for foodborne illness caused by Listeria.

According to the USDA’s Crystal McDade-Ngutter, Ph.D: “Listeria monocytogenes is a dangerous bacterium that you should be on the lookout for all year round—especially in the summer months. Listeria can cause a foodborne illness called listeriosis. It can grow at refrigeration temperatures and is one of the deadliest foodborne illnesses.” Listeriosis can be fatal, and is especially dangerous to numerous populations, including pregnant women.

For those expecting or hosting someone that is expecting at their next summer barbeque or picnic, consider these preventative measures that can help keep pregnant women and their mini-barbeque/picnic goer safe this summer:

  • Do not eat hot dogs, luncheon meats, or deli meats unless they are reheated until steaming hot.
  • Avoid getting fluid from hot dog packages on other foods, utensils, and food preparation surfaces, and wash hands after handling hot dogs, luncheon meats, and deli meats.
  • Do not eat soft cheeses such as feta, Brie, and Camembert, blue-veined cheeses, or Mexican-style cheeses such as queso blanco, queso fresco, and Panela, unless they have labels that clearly state they are made from pasteurized milk.
    • It is safe to eat hard cheeses, semi-soft cheeses such as mozzarella, pasteurized processed cheese slices and spreads, cream cheese, and cottage cheese.
  • Do not eat refrigerated pâté or meat spreads.
    • It is safe to eat canned or shelf-stable pâté and meat spreads.
  • Do not eat refrigerated smoked seafood unless it is an ingredient in a cooked dish such as a casserole. Examples of refrigerated smoked seafood include salmon, trout, whitefish, cod, tuna, and mackerel which are most often labeled as “nova-style,” “lox,” “kippered,” “smoked,” or “jerky.” This fish is found in the refrigerated section or sold at deli counters of grocery stores and delicatessens.
    • It is safe to eat canned fish such as salmon and tuna or shelf-stable smoked seafood.
  • Do not drink raw (unpasteurized) milk or eat foods that contain unpasteurized milk.
  • Use all refrigerated perishable items that are precooked or ready-to-eat as soon as possible.
  • Clean your refrigerator regularly.
  • Use a refrigerator thermometer to make sure that the refrigerator always stays at 40 °F or below.

Follow these tips to ensure that you and your little one have a fun and safe summer. For additional summer food safety tips, check out Krisina Beaugh’s “Checklist For the Perfect Summer Picnic.”

Tags: , , , , , , , , ,

Making Sense of Listeria

Listeria monocytogenes (ABC News)

Listeria monocytogenes (ABC News)

The Centers for Disease Control estimates “approximately 1600 illnesses and 260 deaths due to listeriosis [infection caused by listeria] occur annually in the United States.” Even though responsible for fewer illnesses than other pathogens that are out there, listeria’s relatively high mortality rate (especially for certain segments of the population) naturally resonates with both consumers and food producers as a focus for concern. This has especially been the case with numerous high-profile listeria cases making headlines in the past several months.

Consumers may be surprised to find out that, opposed to being some isolated super-bug, “Listeria monocytogenes is commonly found in soil and water. Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin, such as meats and dairy products.” Beyond that, food processors, understanding the threat that listeria presents, are especially concerned with the fact that: “When Listeria bacteria get into a food processing factory, they can live there for years, sometimes contaminating food products.”

So what is to be done to combat listeria?   Consumers can check out information on prevention from the CDC here and information from the FDA on proper handling of ready-to-eat, refrigerated foods here. The continuing presence of listeria in the headlines will no doubt also give pause for many food processors to review internal practices/standards, and review local, state, and federal resources to address the issue. Fortunately, risks can be minimized by utilizing programs and products that target some of the following areas: cleaning and sampling; ensuring proper temperatures when processing and handling food; and separating foods and parts of the production/preparation process to avoid cross-contamination.

To assist producers find products that can be of use, Nelson-Jameson has compiled a collection of products, including testing/sampling supplies, color-coded products, and numerous other offerings to both test for and prevent listeria concerns. You can check out these products here.

Tags: , , , , , , , , , , , , ,

Avoid “Blech” Friday: Carefully Handle the Leftovers!

Source: Food Network

Source: Food Network

In our house, there are two camps when “Black Friday” hits: the “Dedicated Shoppers” and, those like myself, the “Thanks, I’m Not Giving Up” eaters.

The “Thanks, I’m Not Giving Up,” population, still basking in the glory of the stomach-stuffing of the previous day, shuns leaving the home in favor of recreating the glory of Thanksgiving though various helpings of leftovers throughout the day. Often, this is done in a traditional wardrobe of elastic-waist fleece pants and a hooded sweatshirt. In such regalia, the following exchanges may take place (in one’s head):

Q: “Would I like a mound of reheated green bean casserole?”
A: “Please…I think it only gets better on the second day!”

Q: “Care for some stuffing reanimated with a healthy dose of leftover gravy?”
A: “Well, it is the holiday season…”

Q: “Can I fit the rest of the turkey leftovers into one sandwich?”
A: “Well, I suppose everyone else ate while they were out shopping…”

Much like with Black Friday shoppers, it pays to plan, my fellow “Thanks, I’m Not Giving Up” eaters! As soon as Thanksgiving is over, start thinking strategy! To avoid making it a “Blech Friday,” (the natural enemy of seasonal reheat-aficionados) consider some of these tips from Diane Van, Food Safety Education Staff Deputy Director of the USDA Food Safety and Inspection Service:

Continue reading

Tags: , , , ,
Comments Off on Avoid “Blech” Friday: Carefully Handle the Leftovers!