Cutting Boards & High Bacterial Count

Introduction

Cutting boards used to slice meat may become contaminated by organisms such as Salmonella, Staph aureus, Pseudomonas aeruginosa,Clostridium, etc. The sources of these infective organisms include worker’s hands, cutting utensils and surface carcase contamination. Thereafter, all meat products that are cut on the same board may become contaminated, the organisms then multiplying on storage to ultimately reach infective doses. Although these boards are rinsed off every now and then, plain tap water will not removen sufficient organisms as the board is fatty from the meat and the water may not penetrate sufficiently through this fat to “mechanically” remove the bacteria, i.e. as a result of water flowing over the surface of the board. This is especially true when deep grooves have been etched into the surface from damage by knives. The use of a wet cloth to give a “perfunctory swipe over the board” is even more hazardous as bacteria start to breed in the cloth fibres and contaminants may be spread to other boards by workers using the same cloth. Obviously disinfectants that are hazardous to ingest or cause meat discoloration cannot be utilised.

Anolyte is a disinfectant with no adverse side effects. Anolyte is simply Electro-chemically activated ( EC-A) water, which is produced by passing a saline (salt ) solution through a reactor where it is split into two forms – Anolyte and Catholyte. Neither Anolyte nor Catholyte are toxic even when ingested. Thus they are safe for use on cutting boards. However this extremely novel method has not been used to date in South Africa to improve the hygiene in the meat-processing industry. Anolyte has a bactericidal effect as the active ionised radicals damage bacterial membranes, ultimately causing the death of the organism. Anolyte can be produced on-site in meat processing companies in large volumes for the easily affordable cost of the low monthly rental of the ECA (Electro-chemical activation) unit.

 

* Radical Waters (Pty) Ltd. e – mail: radwat @ intekom.co.za

 

Catholyte is produced at the same time as the Anolyte. It has a detergent-like effect in that it can loosen organic material. Thus, from the same ECA unit one can both remove fat and sterilise with the two components. Neither product is in any way toxic to the environment. We feel that there is a need for adequate hygiene at a low cost in South African meat processing plants and that Anolyte is an effective means of achieving this. However, trials of a similar product, Sterilox, in the medical field, showed that the efficacy of the sterilising action was greatly reduced when organic soiling was present in the product to be treated, requiring laborious pre-soak techniques. (this would include blood, serum, fat, etc). What makes our approach different is that we utilise Catholyte as a dispersal agent for the organic material present.

 

Cutting boards are extremely difficult to clean efficiently because of the fat layer and we felt that it would be a worthwhile study to determine the effect of Anolyte on cutting boards both when used alone as a bactericidal agent and also when used in conjunction with Catholyte .To this end we conducted two trials on cutting boards:

 

  • The initial trial was done on cutting boards that were initially clean but for the purposes of the study had been deliberately contaminated by us with meat that contained large numbers (even exceeding that of a worst-case scenario) of a mixture of Gram-positive and Gram -negative bacteria.
  • The second trial was conducted using the actual cutting boards used in the meat processing companies. These boards are in continuous use throughout the day with an occasional rinse-off in water. Because the meat cut often has a high fat content, it coats the surfaces of the boards, making them a breeding ground for bacteria. The fat layer also prevents removal of bacteria by means of water and/or detergent and it was found that even scrubbing was not particularly effective. The boards, as can be seen in the results, contained disturbingly high numbers of bacteria and are a potential vehicle for transmitting infective organisms like Salmonella.

Materials and Methods:

 

Trial A: The effect of Catholyte and Anolyte on cutting boards with a relatively low fat
layer.

Homogenised mince- meat (slurry) was deliberately infected with the following organisms: B.subtilis, Staph epidermidis, E.coli and Ps. aeruginosa. The number of colony-forming units or CFUs (total of all the organisms mixed with the meat) was 107 per ml of slurry. The slurry was rubbed into the cutting boards and allowed to dry for 2 minutes. All boards were rinsed for 1 minute in running tap water. as it was assumed that this would be the general practice used by Butchers prior to the final cleaning procedure The following comparative tests were done to determine the effectiveness of Anolyte:

  • Sample A was not treated with anything (baseline).
  • Sample B was treated with Anolyte only for 10 minutes, then rinsed for 5 seconds in tap water to remove any Anolyte (in case a bacteriostatic effect was present)
  • Sample C: – the same procedure as above was used to test detergent only, i.e. no Anolyte.
  • Sample D: Soap 10 minutes, rinsed off for 5 seconds, followed by Anolyte for 10 minutes
  • Sample E: Soap for 10 minutes, Anolyte for 10 minutes, then fresh Anolyte for 5 minutes.

All of the cutting boards tested by these methods (A – E) were sampled for the number of bacteria present on the surface as follows:

  • An area of 5 square cms was swabbed with a cotton-wool tipped swab. This was placed in 1.0 ml of sterile water and vortex-mixed for 5 seconds to dislodge the organisms. This first tube was called the “neat” concentration.
  • From this first tube a 1/100 dilution was made in case the number of colony-forming units (CFUs) was too high to count.
  • A 0.1-ml sample was removed from both the neat and the 1/100 tubes. These were spread over the surface of a nutrient agar plate.
  • All plates were incubated overnight at 37oC and read the following morning, using a grid to assist in counting the number of CFUs.
  • Results were multiplied by 10 to give the result per ml as 0.1 ml was spotted on the plates. The dilution factor was also taken into account where applicable.

Trial B: The effect of Catholyte and Anolyte on cutting boards in continuous use in butcheries, and covered with a dense fat layer

Cutting boards were obtained at the end of a busy day in a meat processing plant. The boards were covered with a layer of blood and fat that was hardly decreased when rubbed with a washcloth. The boards were tested in the following manner:

  • Sample F: A 5 square centimeter area was swabbed on a board which had had no treatment applied. This swab was placed in 1.0 ml of sterile water and vortex-mixed, dilutions being made as described above in protocol A This represented the baseline.
  • Sample G: The board was immersed in hot water (45 o C) for 30 minutes.
  • Sample H: The board was soaked in hot water for 30 minutes, and then soaked in Anolyte at room temperature for 30 minutes
  • Sample I: The board was soaked in hot Catholyte (45 o C) for 30 minutes
  • Sample J: The board was soaked in hot Catholyte for 30 mins. and then soaked in Anolyte at room temperature for 30 minutes.

Results

The results of the two studies are given in the tables below. Colony counts refer to the total number of mixed organisms cultured. The tap and sterile water controls showed no bacterial growth. The viability controls were satisfactory.

Study on Cutting Boards

Discussion

From these results, it seems that Anolyte is certainly effective in drastically reducing bacterial counts from unacceptably high levels to counts so low that they are well into margins considered to be non-hazardous regarding disease transmission. The use of an EC-A device on the premises of a meat processing company would provide a cheap source of disinfecting agent as well as a fat-dispersing agent. The Anolyte could be placed in plastic troughs whilst staff are on lunch break to soak. Catholyte could be kept warm in a simple water-bath device with a thermostat similar to that found in a fish-tank. Little training is required to operate an EC-A device, once the company has purchased the unit. The only cost involved thereafter in production is the purchase of normal salt (iodinefree).

Conclusions

The levels of micro-organisms present on the surface of cutting boards is extremely high, with the ever-present risk of food-poisoning organisms being transmitted to meat destined for human consumption. Anolyte is an effective agent for eliminating bacteria from the surface of cutting boards. As an EM-A unit can be installed on-site at the meat processing factory, the technology is readily available. The use of such a product would markedly decrease the chances of cross-contamination of products as happens when surfaces of boards are wiped with wet cleaning cloths (swabs). Further studies to determine what other use this technology may have in the food industry is desirable.