Risk analysis further increases the shelf life of cooled products
“By conducting a risk analysis for our clients and identifying the microbiological risks in their chilled products, our primary objective is usually to determine shelf life,” says Justus Veenemans, a food technologist at TOP BV. “But the analysis can offer much more. We also map out how our clients can improve their processes and extend the shelf life of their products.”
When food producers approach TOP for a risk analysis, Veenemans doesn’t have a standard approach that he can simply retrieve from his laptop’s hard drive. “There are too many variables for that,” he says. “In most cases, we look at around a dozen pathogens, usually bacteria. Listeria monocytogenes and Bacillus cereus are practically always included, but we also consider other organisms. Which ones exactly depend on factors such as the composition of the food, the process, and the raw materials.”
Pathogens are almost always present in food, even if the producer uses high-quality ingredients and follows hygienic practices. “You always have to consider Listeria,” Veenemans gives as an example. “Listeria can simply be in the air and spread through the air conditioning and fans in a production facility.”
Listeria thrives at relatively low temperatures up to 4 degrees Celsius and can survive at a pH value of 4.4. Due to these properties, Listeria is considered a true nuisance in the food industry.
The amounts that can end up in a food product through this route are extremely small. However, bacteria can multiply rapidly. Even minuscule amounts of bacteria or fungal colonies can eventually grow enough to spoil the taste, odour, or appearance of a food product. Consuming a food product in which Listeria has been able to grow unchecked can even cause food poisoning.
“By establishing an expiration date, we can protect the consumer,” says Veenemans. “But first, we need to know which populations of pathogens we might encounter in the worst-case scenario.”
The engineers and microbiologists at TOP derive this knowledge from information already available to the producer or from certificates provided by ingredient suppliers. If, for any reason, it is necessary to supplement that information, TOP consults scientific literature. This happens, for example, when there are no data available, or when TOP’s experts have doubts about the accuracy of the provided figures.
“It sometimes happens that a producer uses herbs or spices that are documented to have virtually no traces of bacteria,” Veenemans explains. “Herbs and spices come from nature. It is not possible to sterilize them without compromising the taste. If, according to the documents, herbs and spices are nearly sterile, we take the liberty of looking up values that microbiologists have previously found. Those values are usually higher than what is stated in the certificates, so we use those figures.”
TOP feeds this information into its models, which predict the growth of bacterial populations based on the process conditions and the precise composition of the product. The complexity of the models increases with the complexity of the product in terms of both the process and composition. Modelling the growth of microorganisms in ready-to-eat salads and chilled soups and sauces, for example, requires more comprehensive considerations than modelling in cut vegetables.
The outcome of TOP’s modelling work is more than a reliable determination of the expiration date, as both TOP and its clients have discovered.
“Once we have completed a risk analysis, we also identify the vulnerable points,” clarifies Veenemans. “That means we can indicate how the producer can extend the shelf life of their product. To provide a realistic example, it is quite possible that by addressing such a critical point, we can increase the shelf life from 8 days to 2 weeks.”