Arsenal's squad hit with a bout of food poisoning in China causing Per Mertesacker and Olivier Giroud to miss the victory over Bayern Munich

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Arsenal's squad has been hit by a bout of food poisoning in China.

Per Mertesacker and Olivier Giroud were unable to take part in a 1-1 draw against Bayern Munich.

Sead Kolasinac started but was forced off in the first-half after throwing up on the pitch.

Arsene Wenger said an Arsenal doctor believed the virus in the camp to be food poisoning

Arsenal won in a penalty shoot-out to decide the winning team but were more concerned about the lengthy casualty list.

Theo Walcott and Aaron Ramsey were also unwell but able to come on from the bench. One of the backroom staff has also been suffering from sickness.

Laurent Koscielny was absent with a back problem and assistant manager Steve Bould has been flown home after requiring surgery in Australia to cure a hernia in his neck.

'We have a virus in the camp,' said Wenger. 'The doctor thinks it is food poisoning. Mertesacker and Giroud were sick. Kolasinac was sick. Theo Walcott and Aaron have had a little bit of food poisoning as well. I don't know what they ate.'

New signing Sead Kolasinac was forced off in the first half after throwing up on the pitch

The stifling heat of Shanghai, where temperatures have been touching 40C, combined with the gruelling pre-season training sessions has tested the players.

'It was a shock to come from Australia where we were freezing,' said Wenger. 'We decided to work very hard on Monday and Tuesday and so I was a bit scared that we could have big problems.

'In the first-half we suffered a bit and second-half we were shaper and Bayern dropped as well. We had to dig deep and think we will benefit from it.'

It raises questions about the sense of travelling the world while preparing for the season. Arsenal will move on to Beijing where they face Chelsea on Saturday in the fourth and final game of their tour.

Olivier Giroud trained but was too unwell to play during Arsenal's 1-1 draw with Bayern Munich

Wenger said: 'If you ask me is it an ideal way to prepare physically, I say certainly not.

'Does it have other advantages? Yes, because we can meet fans from all over the world. The bonding is easier because we live together for two weeks. On that front it can be positive. But the real answer will be given by the way we start in the championship.'

It was a tiny revenge for last season's 10-goal drubbing against Bayern over two legs in the Champions League but Wenger refused to read too fat into it.

'I don't think this kind of games wipe out what happened last season,' said the Arsenal boss. 'We will always remember that. We had a nightmare last season in the second-half.

Wenger said he was keen not to draw too many conclusions despite the result in Shanghai

'But it's still good to win against a team like Bayern. It can help confidence and we have to continue to prepare well. We have been away for 11 days and it helps us push on into the last step.

'I don't want to draw conclusions. It is a preparation game. We worked very hard in the last two games and what was important to get another game physically. Let's continue to prepare and show the winning mentality when the season starts.' 

Bould underwent an operation in Australia, where Arsenal played the first two games of the tour, to ease the pain of his hernia. He is doing well at home, according to the manager.

Aaron Ramsey came off the bench for Arsenal in the 62nd minute despite feeling unwell

'We had to do it in Australia and he couldn't travel,' said Wenger. 'He went home on Saturday and he's OK. He went home and he's good.'

Arsenal trailed in the first half to a penalty from Robert Lewandowski but equalised with a header from Alex Iwobi, which was the final touch of the game.

Back-up goalkeeper Emiliano Martinez saved two Bayern penalties as the Londoners won the shoot-out 3-2.