Dairy leads the way with listeria environmental monitoring

The last few months have been dominated by discussions around Listeria monocytogenes. For food safety news to have been on the front pages of every major South African newspaper is unprecedented. Although the Department of Health has named the so-called source, this should not mean we can take our eye off the ball.

Dairy-sector

It is the right time to ensure robust preventive programmes are in place so that this scale of outbreak never takes place again. In addition to reviewing cleaning and sanitation schedules, re-evaluating personal hygiene regimes and maintenance activities you should also be implementing a listeria environmental monitoring programme (LEMP).

What about South Africa?

There has been much talk in the press about lack of regulation in relation to listeria. Although levels of regulation may be the subject of debate, the principles of control have been covered in national standards on hygiene. They are even included in the compulsory specification for frozen seafood products.

Taking a stand against Listeria monocytogenes, the Dairy Standard Agency published a bespoke guideline to assist the South African dairy sector. Although this guidance is focused on practices in the dairy industry, its application is universal.

Drawing inspiration from US dairy industry guidance and with the input of esteemed South African academics, this easy-to-use guide underlines the importance of many building blocks of your food safety management system. Specific touch points are stressed that, if overlooked, can lead to problems with Listeria monocytogenes in your facility. These controls, if properly implemented, will ensure control of all pathogens. That is the point of your food safety management system.

1. Ensuring raw and pasteurised products are effectively separated.

Listeria monocytogenes has been associated with raw milk. The CCP of pasteurisation, if properly validated and controlled should eliminate the hazard. Post pasteurisation recontamination is the concern and should be the focus in ensuring adequate and effective separation of activities, personnel, and equipment. The same principles would apply to any process where raw and heat-treated products are handled. Post treatment recontamination must be avoided at all costs.

2. Controlling the environmental conditions and practices (GMP’s)

Although personnel hygiene is such a basic requirement, controlling people is anything but basic in application. Providing the right protective clothing, handwash basins and boot washing facilities is the easiest part. Ensuring effective adherence to protocols is the challenge. Given the current food safety crisis we are facing, it is likely all your employees will have some knowledge of listeria. It is a good time to cement this knowledge with more training on how it is spread in your facility; and the importance of handwashing and control of footwear. It is also time to bolster supervision activities. Paying for an extra supervisor to ensure the correct behaviours will be a small price to pay in relation to the damage of a product recall.

3. Effective equipment design and maintenance

Controlling the environment in a dairy can be very challenging. Steam, water and condensation can wreak havoc with floors and ceilings, creating ideal growth niches for Listeria spp. A zero-tolerance approach is essential to ensure harbouring does not take place. Given the persistent nature of Listeria monocytogenes and its ability to form biofilms, design and construction of equipment is critical to ensure proper cleaning takes place. Maintenance staff will need to be trained on the pathogen; how to recognise possible growth sites and the right way to eliminate these from a design and maintenance perspective.

4. Cleaning and sanitising programmes

The DSA Listeria guide indicates that a well designed, effective cleaning and sanitising programme is an essential element of the full pathogen control equation. Enhanced cleaning procedures are proven to compensate for weaknesses in facility or equipment design until improvements can be implemented. Both routine and non-routine cleaning regimens are essential to remove bacteria and prevent bacteria from potentially becoming persistent.

Your master cleaning schedule is in place, but is it working? Don’t assume anything.  All elements of your cleaning programme should be interrogated, including the following:

  • what chemicals are used
  • at what concentrations
  • contact time applied
  • temperature of CIP cycles
  • cleaning methods
  • effectiveness of post cleaning inspections.

5. Environmental pathogen monitoring

Once the above is in place, environmental monitoring starts to make sense. Environmental sampling has played a huge role in this listeriosis outbreak. If you haven’t been sampling your environment before, you should have started already. Using a risk Listeria spp -based approach, a robust sampling plan should be set up to identify Listeria spp. In the environment is a broad indicator group which, when detected, signals that conditions are also favourable for L. monocytogenes growth or survival. The goal of a LEMP is to aggressively look for, find, and eradicate all Listeria spp. from the processing environment, ensuring the absence of L. monocytogenes. The number of samples, the sampling sites, and the recommended actions to take for positive results are defined.

The guideline document gives good advice for all sectors where products that can sustain the growth of Listeria monocytogenes are handled. You should follow it.

AUTHOR: Linda Jackson