Protection concepts

Listeria Protection for Food-Producing Companies

Listeria – Occurence and Risks

Listeria is a rod-shaped bacteria which naturally occurs in almost all environments – on plants and in the intestines of humans and animals. The Listeria monocytogenes species is characterized by its high degree of resistance.

Why is listeria dangerous?
Listeria monocytogenes can cause listeriosis in humans, a rare but serious form of food-borne infection which must be reported to the authorities.

In healthy adults the infection is generally harmless with sufferers experiencing flu-like symptoms. It can, however, cause severe illness or even death among risk groups such as the elderly, those who are immunocompromised or babies. Pregnant women are also particularly at risk as they can pass on the infection to their baby, leading, among other things, to premature or stillbirth.

Characteristics of Listeria monocytogenes

  • L. monocytogenes is resistant and able to withstand deep freezing and drying processes.
  • The ability of L. monocytogenes to survive and grow in food depends on technological treatment and/or the manufacturing process as well as the ingredients in the food.
  • L. monocytogenes can be killed by heating the product to temperatures over 70 °C (min. 2 minutes)
  • L. monocytogenes can also grow at temperatures ranging from -2°C to + 4°C (e.g. in a fridge)
  • Long storage periods in a chilled environment and where oxygen is scarce (e.g. in vacuum packaging) provide L. monocytogenes with good opportunities for growth (in comparison to competing bacteria)
  • Subsequent contamination of heated animal- or plant-based food can be caused by poor hygiene when handling raw materials and intermediate and end products during manufacturing, e.g. due to insufficient personal hygiene (hands in particular) or unclean machine components (e.g. of packaging machines) and equipment

The AVO Listeria Protection Concept

Legal regulations as per Annex I, Regulation 2073/2005

The principle behind the AVO protection concept

If the food business operator can demonstrate by historical documentation that he uses the AVO protection concept without any gaps, has an effective HACCP-based food safety concept and that growth of L. monocytogenes in the corresponding products is not supported, then the product is automatically placed in Category 1.3.

AVO Products which can be used within the Scope of the Protection Concept

Growth of L. monocytogenes is primarily dependent on the following factors:

  • presence of a competing flora, e.g. competing ripening cultures
  • the pH level
  • salt concentration
  • the presence of organic acids (e.g. acetic acid, lactic acid)
  • preservatives (e.g. benzoic and sorbic acid)
  • the chilling temperature

The AVO product range offers effective products to maintain freshness:

Listeria Protection for Spreadable and Sliceable Raw Sausage

Protective Cultures

  • Microorganisms whose microbiological and enzymatic properties aid the fermentation process in numerous ways.

Defined, standardised addition of starter cultures provides an important contribution when manufacturing fermented meat products:

  • Best possible reproducibility
  • Optimum process control
  • Highest level of product safety and quality

Protective cultures are:

  • Microorganisms which are added to food to reduce the risks presented by pathogenic or toxigenic microorganisms (SKLM, 2010)

The following modes of action are employed:

  • Competitive inhibition effect
  • The use of lactic acid bacteria to reduce pH levels and thus suppress pathogenic germs
  • Formation of antagonistic metabolites (formation of bacteriocins) – inhibition of gram-positive bacteria such as listeria

Quality Control of Bacteriocin Formation Capacity

  • Every bacteriocin-forming protective culture delivered to us is supplied with an analysis certificate including documentation of the bacteriocin effect 
  • In addition to this, we subject every incoming batch of a bacteriocin-forming protective culture to an agar diffusion test to establish its bacteriocin formation capacity

Bacteriocin formation capability is tested by measuring the diameter of the inhibition zones which are formed during incubation. The result is calculated as the mean value of the four punched holes.

Challengetest for Teewurst Sausage

This test was carried out using a Teewurst sausage manufactured using the new AVO Meisterclub raw sausage protective culture Art. No. 1589500 (for 50 kg), AVO Meisterclub raw sausage protective culture Art. No. 1589600 (for 100 kg) and a standard ripening culture, in this case AVO Meisterclub starter cultures for spreadable raw sausage  Art. No. 638300.

The Advantages of AVO Protective Cultures

Can be used for any kind of raw sausage and in particular for products such as Teewurst, Pfefferbeisser, Mettendchen, Kohlwurst, etc.:

  • Product safety thanks to the formation of bacteriocins (metabolic product of the protective culture) which kill gram-positive bacteria (such as listeria)
  • Inhibition spectrum against all product-relevant listeria
  • The efficacy of AVO protective cultures has been confirmed and documented by a challenge test in an accredited laboratory
  • The bacteriocins work across the usual pH spectrum and are thus also effective at a pH value of 4.7 without affecting the flavour profile.
  • Use of AVO protective cultures includes an EU Regulation 2073 / 2005-compliant documented prevention system which clearly demonstrates that listeria is killed

How AVO Protective Cultures work

  • The AVO protective culture is added to the product in addition to the ripening culture
  • The bacteriocins form at temperatures from 14°C upwards
  • The bacteriocins work immediately
  • They continue to be effective even when the cultures are no longer active
  • Declaration: “Ripening cultures”

AVO Protective Cultures-Products