According to the MLA, 86 to 314 cases of Listeriosis were linked to the consumption of branded Mexican-style cheese in the US, resulting in a 30 per cent mortality rate among those infected. The pathogen was later traced back to the factory, and it was discovered that raw untreated milk was added to the pasteurised cheese to enhance flavour.
As Listeria Monocytogenes is a ubiquitous organism that is found in a wide variety of environmental niches, it can be extremely difficult to eliminate from the processing environment, explained Mr May, and instead particular emphasis should be placed on minimising the risk as much as possible.
“Data shows the rate of notifications [of Listeriosis] has remained steady over the last 10 years,” he says.
“As it is difficult to completely eliminate the risk…communications campaigns targeted at vulnerable populations, have been developed to improve awareness.”
The steps you can take to protect your plant
Microbial contamination can severely impact a food processing plant’s brand equity, authority and reputation, so it’s vital to follow FSANZ’s two-step approach to reduce the risk of Listeria spread.
1. Environmental Monitoring
The food processing environment should be regularly monitored and tested for L. monocytogenes or a surrogate such as Listeria spp. This is particularly important in facilities producing ready-to-eat foods that can support the growth of listeria, and should be undertaken to verify that cleaning and sanitation programs are working and there is control of niches and harbourage sites.
Sampling and testing methods used should be sufficient to provide confidence that the environment is under control or to help clearly identify that further follow up actions are required.
2. Process Control
Cross lot testing of finished products should be implemented to assess the performance of food safety control systems from within the plant. This helps to verify that the production and processing controls put in place are working effectively.
To ensure that corrective actions are being implemented before microbiological criteria is exceeded; a sample schedule should be put in place as appropriate to the operations of the food business.