Microbiology

• Deter­mining the micro­bi­o­log­ical status of foods and detec­tion of path­o­genic germs such as Salmo­nella, Listeria mono­cy­to­genes and Campylobacter
• Veri­fi­ca­tion of the best-before date
• Rapid methods (Vidas) for salmo­nella and Listeria monocytogenes
• Sensory eval­u­a­tion
• Conducting follow-up studies to deter­mine or monitor compli­ance with best before or the use by date
• Imple­men­ta­tion of the manda­tory micro­bi­o­log­ical tests according to Regu­la­tion (EG) no. 2073/2005 on the micro­bi­o­log­ical criteria for food
• Micro­bi­o­log­ical moni­toring of incoming goods for plant and animal raw mate­rials and/​or semi-finished products
• Micro­bi­o­log­ical analysis of the clean­li­ness and disin­fec­tion level of equip­ment and surfaces
• Sampling of drinking water for micro­bi­o­log­ical analysis
• Micro­bi­o­log­ical analysis of drinking water in accor­dance with current potable water regulations
• Veri­fi­ca­tion of the desig­nated commer­cial classes for fresh and frozen poultry and eggs
• Testing of eggs for their degree of fresh­ness (air chamber height, yolk index, Haugh units
• Chal­lenge testing

According to the Food Infor­ma­tion Regu­la­tion (FIC), a best-before date (BBD) must be indi­cated for foods that are marketed, and a use-by date must be indi­cated for perish­able foods. Excep­tions to this are listed in appendix X of the FIC.

The best-before date indi­cates the date until which the food retains at least its specific prop­er­ties under compli­ance with the spec­i­fied storage condi­tions. While prod­ucts with an exceeded best-before date can still be consumed, prod­ucts with a stated use-by date may no longer be consumed after this date.

Estab­lishing the best-before and use-by dates

The deter­mi­na­tion of the best-before date or the use-by date is the respon­si­bility of the person marketing the product. Various influ­encing factors, e.g. ingre­di­ents, manu­fac­turing process, pack­aging, must be taken into account. If empir­ical values or studies on compa­rable prod­ucts are already avail­able, these can be used as a basis for deter­mining the best before date. However, it is not always possible to use existing data. In such cases, it is recom­mended to carry out a storage test to deter­mine the best before/​use by date. This test is also suit­able for checking an already deter­mined best before date.

In a storage test, the consid­ered food is stored in real time under real condi­tions until the possible/​deter­mined best before date. At previ­ously deter­mined dates, a micro­bi­o­log­ical, sensory and chem­ical exam­i­na­tion of the samples is carried out for possible changes during storage. This proce­dure is suit­able for foods with a rela­tively short shelf life.

For foods with a long shelf life, real-time storage is not suit­able. For these foods, the ​“reac­tion rate-temper­a­ture rule” (RGT rule) can be used in a storage exper­i­ment to shorten the storage time. When using the RGT rule, it is assumed that a 10 °C increase in storage temper­a­ture results in a doubling of the reac­tion rate. If, for example, a best-before date of 6 months is spec­i­fied for a product at 20 °C, then storage at 30 °C can allow a state­ment to be made regarding the best-before date after just 3 months. In this case, the micro­bi­o­log­ical, sensory and chem­ical prop­er­ties of the sample are also exam­ined at different times during the storage period.

Influ­encing factors on the best-before date

There are many different factors that influ­ence the best-before date of food. These are:

• ingre­di­ents
• manu­fac­turing process (e.g. whether the product is frozen, ster­il­ized, canned or dried).
• pH value, aw value, etc.
• pack­aging
• storage condi­tions (temper­a­ture, humidity, light, etc.)

The micro­bi­ology and sensory experts at bilacon routinely perform best before date analyses. These tests can be carried out in special climatic cham­bers and analyzed in the laboratory.

Deter­mi­na­tion of the degree of fresh­ness (deter­mi­na­tion of the Haugh units)

The Haugh unit (HU) is used to deter­mine the degree of fresh­ness of eggs. This method is used to deter­mine the egg white quality and is based on the rela­tion­ship between egg weight and the height of the egg white. For this, the egg is first weighed, then broken on a flat glass plate and the egg white height is deter­mined by using a height gauge at a distance of about 1cm from the yolk edge. The Haugh unit can then be calcu­lated from the egg white height and weight.

Deter­mi­na­tion of the yolk color (raw and cooked)

On the basis of the yolk color, it is possible to make state­ments about the feeding or possibly the state of health of the laying hens. The yolk color is deter­mined with a yolk color fan.

Deter­mi­na­tion of the weight class

Eggs are divided into the weight classes S, M, L and XL depending on their weight. For this purpose, the eggs are weighed one by one and the weight must corre­spond to one of the following weight ranges:

XL: ≥ 73g

L: 63 bis < 73g

M: 53 bis < 63g

S: < 53g

Checking for roll marks

By using UV light, it is checked whether rolling marks are visible on the shell of the eggs. In this way it can be possibly proven whether the eggs orig­i­nate from cage rearing.

Air chamber height

The height of the air chamber can be used to make conclu­sions about the fresh­ness of the eggs.

Measure­ment of eggshell thick­ness and strength

With this measure­ment, possible shell defects can be detected.

Complete range of services for eggs

bilacon supports you in all analyses related to your eggs in the course of in-house inspec­tions or inspec­tions ordered by the author­i­ties. This includes:

In the past, there were more and more public recalls of food, espe­cially meat and sausage prod­ucts. The reason for this was a so-called zoonosis, such as the qual­i­ta­tive detec­tion of Listeria mono­cy­to­genes. Chal­lenge testing offers effec­tive protec­tion against such contamination.
Regu­la­tion (EC) No. 2073/2005 lays down micro­bi­o­log­ical criteria for food. These are oblig­a­tory for food producers.
According to the regu­la­tion, food busi­ness oper­a­tors must set up and regu­larly imple­ment one or more proce­dures based on check­point analysis (HACCP prin­ci­ples). These proce­dures must be constantly moni­tored and veri­fied. The entire manu­fac­turing process must be suit­able to inhibit or prevent the spread of path­o­genic germs. Thus, in order to meet the strict criteria of the regu­la­tion, it is not only the quality of the final product that is consid­ered, but the entire produc­tion route.
Chal­lenge tests are used to crit­i­cally examine the manu­fac­turing process of a product. This is the only way to ensure that the measures taken to protect hygiene during produc­tion are suffi­cient and meet the require­ments of Regu­la­tion (EC) No. 2073/2005.

The equip­ment of bilacon GmbH is always state of the art. This enables us to guar­antee precise and fast analyses at all times.

In micro­bi­ology, for example, we work with spiral platers so that processes are auto­mated, simpli­fied and accelerated.

Tobias Stapper
Head of Micro­bi­ology bilacon GmbH
tobias.​stapper@​tentamus.​com
+49 30 206 038 370