The array of hot and cold prepared foods sold through the convenience store channel continues to get more sophisticated as on-the-go consumers seek out fast, yet more (often perceptually) healthful options than the historical c-store snack of a bag of chips or candy bar. These products come with a number of formulating challenges, most notably maintaining freshness and ensuring food safety.
Where ever food preparation takes place, have it be the hand-made sandwiches being packed at a commissary or the manufacturing and later unwrapping of frozen roller bites for a hot display case, food safety is the number-one priority. Manufacturers and operators must never forget that food is perishable, requiring it to be properly handled before, during and after preparation.
Two of the greatest potential foodborne microbiological threats are Listeria monocytogenes and Staphylococcus aureus. Both can occur in the food handling environment, which is why good sanitary practices and time-temperature control must be properly managed. These are the foundation for the four rules to follow to ensure safe food preparation and handling. They are: clean, separate, cook and chill.
Microorganisms spread quickly, from hands to counters to conveyors to foods. Frequent hand washing with warm water and soap — before and after food handling — and using proven sanitizing agents to clean work surfaces and utensils, such as knives and measuring cups, reduces the chance of microbial contamination.
Keep raw meat, poultry and seafood, and their juices away from ready-to-eat foods. The same goes for unwashed produce. Also, keep known allergens separated and labeled.
Properly cooking or pasteurizing animal proteins, as well as animal products such as eggs and milk, destroys dangerous microorganisms. Use a food thermometer or approved time-temperature measuring device to ensure adequate heating.
Most microorganisms grow fastest at temperatures between 40 and 140 degrees F. Chilling food properly and ensuring that refrigerators maintain a constant temperature below 40 degrees F is one of the most effective ways to reduce the risk of foodborne illness. Remember, this is proper refrigeration through the entire supply chain, from receiving ingredients to when the finished food is purchased by consumer.
Microbes are everywhere, which is why clean, separate, cook and chill are so fundamental in commissary operations. This is where many “freshly made” sandwiches and salads are assembled.
Staphylococcus is carried on the human body, with workers’ hands the most direct mode of transfer to food. Staphylococcus thrives in food environments where most other microorganisms cannot survive, such as high-sodium, low-moisture. This microorganism produces a toxin that is heat stable. The toxin can make you sick for a day or two. Death is rare but can occur in the elderly, infants or severely debilitated persons.
Consumption of L. monocytogenes can result in listeriosis, another potentially fatal foodborne-related disease. Listeria is readily transmitted through ready-to-eat meat and poultry products, such as those used in salads, sandwiches and wraps. Similar to Staphylococcus, Listeria resists historical microbial growth inhibitors such as salt and acidity. It also readily grows at refrigerated temperatures; and although freezing temperatures will stop its growth, this hearty bacterium remains viable.
Proper cooking and reheating effectively controls Listeria; however, ready-to-eat meats do not require further cooking prior to consumption. Further, with Listeria omnipresent in the environment, ready-to-eat meats are very susceptible to contamination, as they are repeatedly exposed to microorganisms during slicing, dicing and meal assembly.
Because the presence of Listeria does not change the taste or smell of the food, it goes undetected. This makes it imperative that manufacturers of these products take all possible precautions to ensure food safety.
Commissary operators should consider sourcing ready-to-eat meats formulated with food safety ingredients. This includes US Dept. of Agriculture-Food Safety and Inspection Service-approved antimicrobials, such as organic acids and bacteriocins, as well as vinegar-based ingredients and citrus oils (e.g., lemon or lime juice).
With more involved centralized production facilities, cooking, baking and washing should take place at a nearby commercial kitchen or manufacturing facility designed for the preparation of that specific product. Proximity is important as these are fresh foods with limited shelf life.
For example, chicken breast intended for topping a Caesar salad can be procured in various ways. From a food safety perspective, the riskiest approach is to bring raw chicken into the kitchen, cook it and then dice it. Even bringing in fully cooked chicken breasts and dicing them on site increases exposure to the environment and potential for contamination. Ideally fully cooked chicken breast cubes are delivered in a package size that is easy and quick to work with. You don’t want too large of a package sitting out for an excessive length of time, which warms the product and exposes it to environment contaminants.
Staging assembly is critical to keeping perishable foods at safe temperatures. Colder is always better. This is true through the entire supply chain.
In addition to positively improving food safety, sourcing ready-for-assembly meal components, as compared to cooking and preparing the components in nearby facilities, improves quality control, as incoming foods will have been produced and inspected by the supplier. These products must meet established standards in terms of appearance, color, taste and texture. This in turn enables the commissary operator to produce consistent meals.
When it comes to foods intended for hot merchandising on roller grills or sandwich warmer units, it is paramount that these foods do not burn or dry out on the surface. Meat and poultry must stay moist and should not develop warmed-over flavor. The latter, which is often described as a cardboard taste, develops as the result of lipid oxidation, or the lipids going rancid.
Ingredients that retard lipid oxidation – antioxidants – help extend the shelf life of protein. Oxidative rancidity occurs via a free radical process, where the double bonds of an unsaturated fatty acid undergo cleavage, releasing undesirable volatiles. This process can be suppressed through the exclusion of oxygen, which is necessary for propagation of the chain reaction that causes the unfavorable organoleptic changes in protein, or through the addition of antioxidants, which either terminate the reaction or bond with oxygen, rendering it unavailable.
Proteins vary in their susceptibility to oxidation, with less saturated fats more easily oxidized. Further, leaner meats, such as chicken and pork, seem to be more susceptible to oxidation than beef. Heat accelerates oxidation, which is why foods intended for warm merchandising are highly susceptible.
Traditional synthetic antioxidants are chemically derived, and include ethylene diamine tetra acetic acid (EDTA), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA) and butylated hydroxyanisole (BHT). These are efficient and reliable antioxidants typically used in foodservice products.
However, with today’s consumers increasingly reading food labels and often rejecting products containing ingredients that sound like they were concocted in a lab, processors are embracing clean-label antioxidants. For example, rosemary extract is a concentrated source of phenolic compounds, in particular carnosic acid, which has been shown to retard oxidative rancidity in protein, as well as function as an antimicrobial. Advanced technologies are used to remove or reduce the rosemary taste, yet the ingredient is labeled as rosemary extract or natural flavor.
It is often used alone or in combination with green tea extract, which is a concentrated source of the antioxidants classified as catechins, half of which are the highly effective epigallocatechin gallate (EGCG). Green tea extract also contains an array of other chemicals that work synergistically with EGCG, including gallic acid, carotenoids, tocopherols, ascorbic acid and minerals such as chromium, manganese, selenium and zinc.
Another popular oxygen scavenger is vitamin E. Specifically, vitamin E classified as mixed tocopherols is best recognized for its ability to prevent lipid oxidation in protein.
Scientists are actively exploring all types of clean-label ingredients as potential antioxidants. One recently recognized ingredient is an oat-derived flavor modifier that has been shown to reduce warmed-over flavor in pre-cooked meats, while promoting moisture and flavor retention.