Rapid Testing of Water Samples in the Bottling Plant

Following on from the ATP article in a recent blog, this section describes the procedure for rapid microbial testing of water samples.

Because water samples contain very few bacteria, an enrichment technique is employed. This involves taking a sample aseptically, and expelling it via a syringe through a special filter.

After waiting for 30 minutes to allow the microorganisms to recover from the stress of filtration, the filter housing is opened and the filter swabbed, using the special swab used in the ATP meter.

The swab is put back into the swab tube and activated using the snap and squeeze action. The swab is placed in the ATP meter and the measurement started. Results are recorded from the display.

Simple Microbiological Testing in the Bottling Plant

A new type of dipslide has recently appeared on the market which is double sided and able to detect 4 different groups of organisms:
1. Nutrient agar on one side to detect total counts.
2. Chromomeric coliform, E. Coli and pseudomonas aeruginosa on the other side.

It is a very versatile slide that can be used to dip into liquid samples or used as a contact plate on solid surfaces. The nutrient agar reacts with enzyme to produce a colour change which is specific to the bacteria type, allowing easy enumeration.

When sampling fluids, the sample is taken by immersing both sides of the paddle into the fluid to be tested. Excess sample should be gently shaken from the paddle before replacing in the container.

Surfaces can be sampled by allowing direct contact between the agar surface and the test material. The paddle is flexible and can be bent at the upper end to allow both surfaces to come into intimate contact.

Bacterial recovery rate is about 50% so that sweeping an area approximately twice that of the paddle will give a more accurate result. Afterwards incubate at 30/35 deg C for 24-48 hours, when full enumeration should be complete.

Apart from an indicator of aerobic bacteria (TVC), as shown in the picture above, the reverse side will give an indication of coliforms and Pseudomonas according to the following colour scheme: blue/purple or blue/green colonies = E.coli; pink/magenta colonies = other coliforms; buff colonies = Pseudomonas.

Recycling Plastics from the Bottling Plant

I previously attended a seminar run by the Food and Drink Association in the South West of the UK, entitled “Make Money, Not Waste”. This gave an up-to-date picture of latest developments in recycling and sustainability in general. My interest and perspectives were naturally focused on bottled water applications.

The main waste issues for bottlers are caps, 19L bottles and chemical drums, particularly the 25L size. Unfortunately all three items are made of different kinds of plastic which sometimes deters recyclers from collecting smaller quantities. If you are fortunate enough to be near a recycling site there may be an opportunity to drop off unwanted drums during the course of a delivery round by your drivers. However, this is not always convenient.

The organisation WRAP (Waste and Recycling Action Programme) currently has a study underway to collect plastics from smaller companies and deliver them to recycling points. This is useful for those companies who find it difficult to persuade recyclers to collect smaller quantities.